United States Great Lakes National EPA-905/2-87-002
Environmental Protection Program Office GLNPO Report No. 06
Agency 230 South Dearborn Street April 1987
Chicago, Illinois 60604
ER^ Phytoplankton and
Zooplankton in Lake MmeC
Erie, Huron and
Michigan: 1983
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EPA-905/2-87-002
July 1987
GLNPO Report No. 87-
Phytoplankton and Zooplankton Composition, Abundance and Distribution:
Lake Erie, Lake Huron and Lake Michigan - 1983
Volume 1 - Interpretive Report
by
Joseph C. Makarewicz
Department of Biological Sciences
State University of New York at Brockport
Brockport, New York 14420
September 1985
Project Officer
Paul Bertram
For
U.S. Environmental Protection Agency
Great Lakes National Program Office
Chicago, Illinois 60604
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ABSTRACT
An in-depth comparison of phytoplankton and zooplankton from Lakes Erie,
Huron and Michigan is presented based on extensive lake-wide surveys during
spring, summer and autumn of 1983. This comparison was achieved by the
application of standard and consistent identification, enumeration and
data-processing techniques of plankton along north-south transects in Lakes
Huron and Michigan and east-west transects in Lake Erie.
For Lakes Erie, Huron and Michigan respectively, 436, 411 and 452 algal
taxa and 71, 61 and 73 zooplankton taxa were identified. Based on indicator
species and species associations, the plankton assemblage was consistent
with a mesotrophic-eutrophic designation for Lake Erie, oligotrophic
designation for Lake Huron, and mesotrophic-oligotrophic designation for
Lake Michigan.
Species lists for each lake are provided. Original source data for each
station visit are provided in the attached microfiche.
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ii
DISCLAIMER
This report has been reviewed by the Great Lakes National
Program Office, U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the
U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
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FORWARD
The Great Lakes National Program Office (GLNPO) of the United
States Environmental Protection Agency was established in
Region V, Chicago, to focus attention on the significant and
complex natural resource represented by the Great Lakes.
GLNPO implements a multi-media environmental management
program drawing on a wide range of expertise represented by
universities, private firms, State, Federal and Canadian
Governmental Agencies and the International Joint Commission.
The goal of the GLNPO program is to develop programs,
practices and technology necessary for a better understanding
of the Great Lakes ecosystem and to eliminate or reduce to
the maximum extent practicable the discharge of pollutants
into the Great Lakes system. The Office also coordinates
U.S. actions in fulfillment of the Great Lakes Water Quality
Agreement of 1978 between Canada and the United States of
America.
This report presents results of the phytoplankton and
zooplankton portions of the water quality surveillance
program conducted on Lakes Michigan, Huron and Erie in 1983
by GLNPO. Results of the physical and chemical portions of
the surveillance program may be found in a companion report:
Lesht, Barry M. and David C. Rockwell. 1985. The State
of the Middle Great Lakes: Results of the 1983 Water
Quality Survey of Lakes Erie, Huron and Michigan.
Publication Number ANL/ER-85-2. Argonne National
Laboratory, Argonne, Illinois 60439.
GLNPO gratefully acknowledges the contribution to this study
of The Bionetics Corporation, with whom GLNPO contracted for
assistance in the collection of samples and for the
identification and enumeration of the phytoplankton and
zooplankton. In particular, we extend appreciation to Norman
A. Andresen, Mark A. Lamb, Louis L. Lipsey, Heather K.
Trulli, Marc Tuchman and Thomas Morse.
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iv
TABLE OF CONTENTS
PAGE
LIST OF TABLES vii
LIST OF FIGURES ix
INTRODUCTION 1
METHODS AND MATERIALS 3
RESULTS 6
Phy top lank ton 6
Annual Abundance of Major Algal Groups. 6
Lake Erie 6
Lake Huron 6
Lake Michigan 7
Seasonal Abundance and Distribution of Major Algal Groups 7
Lake Erie 7
Lake Huron 8
Lake Michigan 9
Geographical Abundance and Distribution of Major Algal Groups 9
Lake Erie 9
Lake Huron 10
Lake Michigan 11
Regional and Seasonal Trends in the Abundance of Common Taxa 12
Lake Erie 12
Cyanophyta 12
Chlorophyta 16
Chrysophyta 19
Cryptophyta 19
Pyrrhophyta 21
Bacillariophyta 22
Lake Huron..... 27
Cyanophyta 27
Chrysophyta.... 31
Cryptophyta 33
Pyrrhophyta 34
Bacillariophyta 35
Lake Michigan 42
Cyanophyta 42
Pyrrhophyta 46
Chlorophyta 46
Chrysophyta 47
Cryptophyta 48
Bacillariophyta • 51
Zooplankton.............. 61
Annual Abundance of Zooplankton Groups 61
Lake Erie.... 61
Lake Huron 61
Lake Michigan 62
Seasonal Abundance and Distribution of Major Zooplankton Groups 62
Lake Erie........ 62
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Lake Huron 63
Lake Michigan..... 63
Geographical Abundance and Distribution of Major Zooplankton Groups.. 63
Lake Erie.... 63
Lake Huron 64
Lake Michigan 64
Size Frequency Analysis 65
Lake Erie 65
Lake Huron 65
Lake Michigan 65
Regional and Seasonal Trends in the Abundance of Common Taxa 66
Lake Erie 66
Copepoda 66
Cladocera 68
Rotifera. 70
Less Common Species 75
Lake Huron 75
Copepoda 75
Cladocera 78
Rotifera 79
Less Common Species 80
Lake Michigan. 81
Copepoda 81
Cladocera....... 83
Rotifera 85
Other Common Species 87
Less Common Species 87
Differences Between the Long and Short Zooplankton Hauls.... 87
Lake Erie 87
Lake Huron 87
Lake Michigan 88
DISCUSSION 89
Phytoplankton. 89
Lake Erie 89
Changes in Species Composition 89
Picoplankton 91
East-West Species Distribution 91
Indicator Species 92
Historical Changes in Community Biomass 93
Lake Huron 94
Changes in Species Composition 94
Picoplankton. 95
Dominant and Indicator Species for the Entire Lake....... 95
North-South Distribution 97
Historical Changes in Community Abundance and Biomass............. 99
Lake Michigan «... .101
Changes in Species Composition...................... 101
Picoplankton 104
Indicator Species 105
North-South Distribution .105
Historical Changes in Community Abundance 107
Zooplankton 108
Lake Erie ,...,..,..,,.,,...,..,,.108
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vi
Changes in Species Composition 108
East-West Species Distribution 110
Indicators of Trophic Status 110
Historical Changes in Abundances 112
Lake Huron 114
Changes in Species Composition 114
North-South Distribution 116
Indicators of Trophic Status ...117
Historical Changes in Abundances 118
Lake Michigan 120
Changes in Species Composition 120
Rotifera 123
North-South Trophic Status 124
Indicators of Trophic Status 125
RECOMMENDATIONS 128
LITERATURE CITED 130
TABLES 138
FIGURES 170
SPECIES LIST
Phytoplankton
Lake Erie 233
Lake Huron .242
Lake Michigan 250
Zooplankton
Lake Erie 259
Lake Huron.... 261
Lake Michigan 263
VOLUME 2 - Data Report Attached Microfiche
Data Sheets for Phytoplankton and Zooplankton
Lakes Erie* Huron and Michigan Attached Microfiche
ACKNOWLEDGEMENTS
This work would not be possible without the computer skills of Mr. Ted
Lewis. I thank him for his continuing effort and dedication.
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Page
138
139
140
141
142
143
144
145
145
147
148
149
150
151
152
153
154
TABLES
Plankton sampling dates for Lakes Erie* Huron
and Michigan in 1983
Latitude and longitude of plankton sampling
stations* 1983
Sample dates and stations for Lake Michigan. 1983
Number of taxa and genera observed in each algal
division or grouping* 1983..
Relative abundance of major phytoplankton divisions
in Lakes Erie* Huron and Michigan
Summary of dominant phytoplankton species occurrence
in Lake Erie during 1983
Summary of dominant phytoplankton species occurrence
in Lake Huron during 1983
Summary of dominant phytoplankton species occurrence
in Lake Michigan during 1983
Relative abundance of taxa and number of taxa and
genera observed in each zooplankton grouping* 1983....
Mean abundances of zooplankton groups during the
study period
Summary of common zooplankton species occurrence
in Lake Erie during 1983
Summary of common zooplankton species occurrence
in Lake Huron during 1983.....
Summary of common zooplankton species occurrence
in Lake Michigan during 1983
Zooplankton species having major differences in
abundances between the long and short hauls* Lake
Erie
Zooplankton species having major differences in
abundances between the long and short hauls* Lake
Huron
Zooplankton species observed in either the long
or short hauls* Lake Huron
Zooplankton species having major differences in
abundances between the long and short hauls* Lake
Michigan
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155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
Zooplankton species observed in either the long
or short hauls. Lake Michigan
Comparison of average abundance and biomass of
plankton in Lakes Erie* Huron and Michigan* April-
October. 1983
Mean maximum abundance of selected common phyto-
plankton species in 1970 and 1983. Lake Erie.
Data from Munawar and Munawar (1976) and this study.
1970 data - graphical accuracy
Total mean phytoplankton biomass for the western*
central and eastern basins* 1983* Lake Erie
Comparison of phytoplankton biomass values between
1956 and 1983 in western Lake Erie
Comparison of abundance of selected species at
offshore sites in August of 1970 and 1983*
Lake Michigan
Phytoplankton abundance in 1962, 1977 and 1983 in
southern Lake Michigan
Species having peak abundances in the western*
central or eastern basin of Lake Erie* 1983
Ratio of calanoids to cladocerans plus
cyclopoids in Lake Erie* 1983
Comparison of mean crustacean abundance for the
sampling period in 1971 (April-November). 1974/75
(April-November) and 1983 (August-October)
Ratio of Calanoida to Cladocera plus Cyclopoida
in Lake Huron. 1983.....
Mean abundance of rotifers in Lake Huron in 1974
and 1983
Cladoceran abundance in 1954* 1966* 1968 and 1983
in Lake Michigan
Copepod abundance in 1954* 1966* 1968 and 1983
in Lake Michigan
The ratio of calanoids to cyclopoids plus
cladocerans geographically in Lake Michigan*
1983
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Payp
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
Lake Erie plankton sampling stations* 1983
Lake Huron plankton sampling stations, 1983
Lake Michigan plankton sampling stations* 1983
Seasonal phytoplankton abundance (4a) and biovolume
(4b) trends in Lakes Erie* Huron and Michigan
Seasonal distribution of algal divisions in Lake
Erie
Seasonal distribution of algal divisions in Lake
Huron
Seasonal distribution of algal divisions in Lake
Michigan
Geographical distribution of major algal divisions
in Lake Erie
Geographical distribution of phytoplankton abundance
on the June and October cruises* Lake Erie
Geographical distribution of major algal divisions
in Lake Huron
Geographical distribution of phytoplankton
abundance on all cruises* Lake Huron
Geographical distribution of major algal divisions
in Lake Michigan
Geographical distribution of phytoplankton
abundance on all cruises* Lake Michigan
Mean seasonal distribution of a) Anacyatia montana
V. minor and AgmenelTurn QUadrUPliCAtUm* b) CflCCQ~
chloris peniocystis and CoelOBPhaeritta naayelianmn.
c) Aptianizomenon flofl-aqUfie» d) Cosmarium sp. and
Oocystia borgeit e) CoelaBtrma microporua and Mono-
raphidimn cQntortunu f) Pediafitrua siaplfis var.
Hiindpnarimn and Mougeotia sp.* Lake Erie
Mean seasonal distribution of a) Haptnphyt-o sp.*
b) Bhodomonae minuta var. nannoplankHca and ChrPomonaa
norgtedtii* c) Stephaoodiacufl niayara* and Stephano-
diacua bindfiranugj d) Rhizoanlenia sp. and Fragilaria
CflPUfiiaa* e) ActiPOSyClUB noimanii f. aubsalsa.
f) Ceratiua hirundinalla. Lake Erie
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X
FIGURE 16
FIGURE 17
FIGURE 18
FIGURE 19
FIGURE 20
FIGURE 21
FIGURE 22
FIGURE 23
FIGURE 24
FIGURE 25
FIGURE 26
Seasonal and geographical distribution of a) Anacvatib
marina> b) Qacillatoria tenuis* c) Oscillator^
1 imnpf.i ca. Lake Erie 185
Seasonal and geographical distribution of a) Merismo-
tenuiggiaai b) Oscillatoria subbrevis. c)
Scenedesmus ecornis. Lake Erie 186
Seasonal and geographical distribution of a) Crypto-
monas eroga* b) Fragilaria crotonensis. c) Tabellaria
flocculosa. Lake Erie 187
Seasonal and geographical distribution of Melosira
granulata. Lake Erie 188
Mean seasonal distribution of a) Anacvstis marina.
b) Coccochioris peniocyBtig» c) Anacvstis thermalie
and Coelosphaerium naegelianunu d) Rhodomonas minu.ta
var. nannoplanktica^ e) Anacvsti s montana var. minor*
f) Cryptomonas eroea and Crvptomonas eroaa var. refle»a*
Lake Huron 189
Mean seasonal distribution of a) Cryptomonas pyre~
noidifera. b) Cyclotella comensis and Cyol Ptella.
comta. c) Cyclotella kuetzin^iana var. pinnPtOPhora and
Cyclotella pcellatat d) StPphflnodiacuB niagaraa and
stephanodiscus transilvaaicua* e) Iflbfillaria
flocculofla and Tabellaria f 1 per.nloaa var. lltteangi
f) Rhizosolenia sp.. Lake Huron 190
Mean seasonal distribution of a) ChrygQSphaerella
1 ongispina, b) Dinobryon iiivergePS and PmofrryOIl
rviindricum. c) Melogira jslandicat d) Fragilaria
^mtonensis. e) Dinobrvon gpciale var. americanum.
Lake Huron 19j
Seasonal and geographical distribution of a) Asterio-
nella formPga* b) Qgcillatoria limnetica. c) Cocco-
chioris filfltajoa. Lake Huron 192
Seasonal and geographical distribution of a) Frayi-
laria intermedia var. fallaX% b) Haptophyte sp.,
Lake Huron 193
Mean seasonal distribution of a) Coccochioris penio-
f-yatis and AnacvstiB montana var. minor* b) Coelp-
flphaerium naegelianum and Qgcillatoria agardhii.
c) Gomphosphaeria lacustris and Qgcillatoria
limnetica. d) StichocPf,f,UB sp. and Monnraphidium
contortum. e) Dinobryon divergens. Dinobryon BOCialfi
var. americanum and Dinobryon cylindricum. f) ChrPQmQPflg
norstedtii and Rhodomonas mimita var. nannoplaaktica*
Lake Michigan. 194
Mean seasonal distribution of a) Cryptomonaa marggonii
and Cryptomoaag ovrenoidifera. b) Cyclotella CQmeQgig
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xi
FIGURE 27
FIGURE 28
FIGURE 29
FIGURE 30
FIGURE 31
FIGURE 32
FIGURE 33
FIGURE 34
FIGURE 35
FIGURE 36
FIGURE 37
FIGURE 38
v. 1 and Cycloteila ££m££, c) Cycletella aichiganiana
and Aaterioneiia formosa* d) stephanodiBCua aiagarae
and stephanodiscus transilyanicuBj e) Xabellaria
fenestrata and Tabellaria flocculosa. f) Fragilaria
crotonensis and Fragilaria vaucheriae. Lake Michigan.... 195
Mean seasonal distribution of a) Melosira italica
subsp. subarctica and Melosira islandica , b) StylP~
theca aurea • c) Qsciiiatoria limnetica > d) Tabel-
laria fenestrata , Lake Michigan 196
Seasonal and geographical distribution of a) Anacvstis
marina* b) Haptophyte sp., c) Rhiznaoignia eriensis.
Lake Michigan 197
Seasonal zooplankton abundance in Lakes Erie, Huron
and Michigan. 198
Seasonal distribution of zooplankton groups in Lake
Erie 199
Seasonal distribution of zooplankton groups in Lake
Michigan 200
Geographical distribution of major zooplankton
groups in Lake Erie 201
Geographical distribution of major zooplankton
groups in Lake Huron 202
Geographical distribution of major zooplankton
groups in Lake Michigan. 203
Size-frequency distribution of zooplankton in Lakes
Erie* Huron and Michigan 204
Mean seasonal distribution of a) Diaptnmus siciloides.
b) Calanoid - copepodite and Cyclopoid - copepodite,
c) Copepoda nauplii, d) Chvdorus BphaeriCUB and
Eubogmina coregoni. e) Piaphaaoaoma leuchteabergianum
and Daphnia retrocurva. f) Asplanchna priodQBta»
Lake Erie 205
Mean seasonal distribution of a) Conochilus unicornis
and Cniiothpca 8p.. b) Kellicottia longispina and
Pioesoma sp.. c) Korateiia cochlearia and Keratella
quadrata. d) Keratella crassa* e) Hotholca laurentiae
and Notholca squamula. f) MQthOlCa fo1iacea>
Lake Erie 206
Mean seasonal distribution of a) Polyarthra dolichop-
tera and Polyarthra vulgaris* b) Eolyarthra major*
c) Gafltropus atvlifer. d) Aacomorpha flCaudjg and
Ancnmnrpha sp., e) Daphnia galeata n"»ndotae .
f) Bosmina lonyiroatria . Lake Erie 207
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208
209
210
211
212
213
214
215
216
217
218
Seasonal and geographical distribution of a) Diaptomua
oregoaeasis. b) Cyclops bicuspidatus thomasi. c)
Tropocvclops praBlBUg mexicanus. Lake Erie
Seasonal and geographical distribution of a) Mesocy-
tlOfiS. fidflXt b) Brachionus sp.. c) Filiaa loneiseta.
Lake Erie
Seasonal and geographical distribution of a) Keratella
earlinae. b) Synchaeta sp., c) Trichocerca cylindrica.
Lake Erie
Seasonal and geographical distribution of a) Tricho-
cerca multicrinis. b) Keratella hiemalis. c) Brachio-
nus caudatus. Lake Erie
Mean seasonal distribution of a) PiaptQmug aah1andi.
b) Diaptomus oregonensis and PiaptOMlB BiciliSi c)
Calanoid - copepodite and Copepoda nauplii, d)Cyclo-
poid - copepodite and Cyclops bicuspidatus thomagj*
e) Tropocvclops prasinus mexicaBUB and MeBOCyclOpB
edax. f) Bosmina longirostris and Paphaia BChodlerit
Lake Huron
Mean seasonal distribution of a) Daphnia galaeta men-
d&La and Paphaia pulicaria. b) Eubosmina coregoni.
c) Aaplanchna priodOBta and Collotheca sp., d) Kera-
tella CQChleariBi e) Keratella crassa. Kpratella
earliaae and Keratella quadrata. f) NothoTca lauren-
tiae and Notholca squamula. Lake Huron
Mean seasonal distribution of a) Polyarthra dolichop-
l£xa and folyarthra major* b) Polyarthra vulgaris,
c) CaetrQPUB stvlifer and Synchaeta sp., Lake Huron....
Seasonal and geographical distribution of a) Diaptomus
minutus. b) Paphaia retrocurva. Lake Huron
Seasonal and geographical distribution of a) Cono-
chilufl unicornis, b) Kpllicottia loagigpiaa. Lake
Huron
Mean seasonal distribution of a) Diaptomus aahlandi.
b) Diaptomus minutus. Diaptomus pregPaeagjg and
Limnocalanus macrurug. c)Calanoid - copepodite and
Copepoda nauplii, d) Cyclopoid - copepodite, e)
Cvclopfi bicuspidatus thomasfii and IrOPOCyclPPg Pra"
sinus mexicanus. f) Daphnia gfilaeta meadPta and
Daphnia pulicaria. Lake Michigan
Mean seasonal distribution of a) Enhnsmina enrcgoni and
Hnlnpedium gibberum. b) Aspianchna priodonta. c) Sya~
chaeta sp., d) Collotheca sp. and Conochilus uaiCPr~
nis. e) KpI1icottia lnnyispina and Gastropug Btylifer*
f) Kprateiia pariinae and Keratella quadrata* Lake
Michigan
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xiii
FIGURE 50 Mean seasonal distribution of a) Keratella cochlearis
and Kerateiia cra£6a% b) Polyarthra dolichoptera and
Polyarthra maisi* c) Polyarthra vulgaris, d) Ascom-
orpha sp. and Ploesoma sp.> Lake Michigan 219
FIGURE 51 Seasonal and geographical distribution of a) PiaptomuB
silicis. b) Bosmina longirostris. c) Paptmia retro-
curva. Lake Michigan 220
FIGURE 52 Seasonal and geographical distribution of a) Notholca
laurentiae. b) Notholca squaaula. c) Notholca fol-
iacea. Lake Michigan 221
FIGURE 53 Seasonal fluctuation of weighted mean phytoplankton
biomass in 1970 and 1983» Lake Erie 222
FIGURE 54 Seasonal abundance of phytoplankton in southern Lake
Huron 223
FIGURE 55 Seasonal abundance of phytoplankton in Lake Huron in 1971
and 1983 224
FIGURE 56 Mean seasonal distribution of total algal and diatom
biomass on selected dates( Lake Huron. 1983 225
Figure 57 Mean number of crustaceans in Lake Erie in 1970 and 1983. 226
Figure 58 Mean number of cladocerans in Western Lake Erie from 1939
to 1983 227
Figure 59 Mean number of copepods in Western Lake Erie from 1939 to
1983 228
Figure 60 Mean number of rotifers in Western Lake Erie from 1939
to 1983 229
Figure 61 Mean number of crustaceans (exclusive of copepod nauplii)
in Lake Huron in 1971* 1974 and 1983 230
Figure 62 Mean number of rotifers in Lake Huron in 1974 and 1983... 231
Figure 63 Geographical distribution of Limnocalanus macrurua.
Diaptnmua aicilia> Holopedium gibberum. Bosmina
ionpi roatrifl. Eubpamina coregoaii Notholca
laurentiae. squamula and fpliacea* Lake
Michigan 232
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INTRODUCTION
The Laurentian Great Lakes ecosystem occupies a unique position
in the development of the United States and Canada and could be
considered as presenting one of the most complex water management
problems in North America. Individually, the Great Lakes rank among
the world's largest with Lakes Huron, Michigan and Erie, the subject
of this report, ranking fifth, sixth and twelfth in size of the
world's lakes. During the past decades, there has been an enormous
population and industrial growth within their watersheds resulting in
the accelerated eutrophication of these water bodies.
As a result of the declining water quality of the Great Lakes,
Water Quality Agreements were signed in 1972 and 1978 between the
United States and Canada. One of the main provisions was to limit the
phosphorus in sewage treatment plant effluents. In addition, many
states and the Canadian provinces have passed legislation on the water
quality of these lakes. These include bans on phosphorus-based
detergents in New York and Michigan and reduction in phosphate in
detergents in the Province of Ontario.
This project reported here was initiated by the United States
Environmental Protection Agency, Great Lakes National Program Office
(GLNPO), to analyze phytoplankton and zooplankton samples from Lakes
Erie, Huron and Michigan taken in 1983. Because phytoplankton are
sensitive to water quality conditions and possess short carbon
turnover rates, the determination of phytoplankton abundance and
species composition have become established as methods to trace
long-term changes in the lakes (Stoerroer 1978, Munawar and Munawar
1982). Similarly, zooplankton have value as indicators of water
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2
quality and structure of the biotic community and have proved useful
for complementing phytoplankton to assess the apparent effects of
water quality conditions (Gannon and Stemberger 1978) and of fish
populations (e.g. Brooks and Dodson 1965) on biota.
An in-depth planktonic (phyto- and zooplankton) comparison is
presented based on extensive lake-wide surveys during spring, summer
and autumn of 1983. This comparison was achieved by the application
of standard and consistent identification, enumeration and
data-processing techniques of plankton along north-south transects in
Lakes Huron and Michigan and east-west transects in Lake Erie.
The primary objectives of this report include:
(1) To organize plankton data for use in eutrophication models;
(2) To characterize the composition and abundance of the
phytoplankton and zooplankton for comparison with past conditions to
the extent that they are known;
(3) To provide firm documentation with which future assessment
of the changes in water quality of the lakes can be made; and
(4) To characterize the water quality by studying the abundance
and autecology of phytoplankton and zooplankton.
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3
METHODS AND MATERIALS
Phytoplankton and zooplankton samples were collected by GLNPO
personnel from Lakes Erie. Huron and Michigan during seven cruises
during the spring, summer and autumn of 1983. Collection dates and
station locations of routine plankton sampling are given in Tables 1,
2 and 3 and in Figures 1, 2 and 3. Locations of sampling sites on
Lake Michigan were not consistent for the year (Table 3). Every other
sampling date alternate east-west stations were sampled (e.g. 5 or 6,
10 or 11; Fig. 3). This selection of sites was based on previous
studies which indicated that adjacent east-west sites were within
homogeneous areas of the lake (Moll et al. 1985). For analytical
purposes, east-west stations were combined, assuming that no
significant difference in species abundance and composition existed
between east-west stations, to give a single north-south transect. On
the last cruise of the year on Lake Huron, samples were taken at a
different set of stations (Fig. 2) and were not included in this
analysis. All sites are also part of the Great Lakes International
Surveillance Program.
An 8-liter PVC Niskin bottle mounted on a General Oceanics
Rossette sampler with a guideline electrobathythermograpb (EBT) was
used to collect phytoplankton. One-liter composite phytoplankton
samples were obtained by compositing equal aliquots from samples
collected at depths of 1 and 2m above the bottom and at as many
5-meter intervals (5,10,15.20m, etc.) as allowed by total water depth.
Phytoplankton samples were immediately preserved with 10 mL of
Lugols solution. 5-6% formaldehyde was added to each sample upon
arrival in the laboratory. The settling chamber procedure (Utermtftil
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1958) was used to identify (except for diatoms) and enumerate
phytoplankton at a magnification of 500x. A second identification and
enumeration of diatoms at 1250x was performed after the organic
portion was oxidized with 30% an<* The cleaned
diatom concentrate was air dried on a #1 cover slip and mounted on a
TM
slide (75x25mm) with HYRAX mounting medium.
Identifications and counts were done by Dr. Norman A. Andresen, Mr.
Mark A. Lamb, Dr. Louis L. Lipsey, Ms. Heather K. Trulli, and Dr. Marc
Tuchman of the Bionetics Corporation.
The cell volume of each species was computed by applying average
dimensions from each sampling station and date to the geometrical
shapes that most closely resembled the species form such as sphere,
cylinder, prolate spheroid, etc. At least 10 specimens of each
species were measured for the cell volume calculation. When fewer
than 10 specimens were present, those present were measured as they
occurred. For most organisms, the measurements were taken from the
outside wall to outside wall. With loricated forms, the protoplast
was measured, while the individual cells of filaments and colonial
3
forms were measured. For comparative purposes, biovolume (jim /L)
3
was converted to biomass (mg/m ) assuming the specific gravity of
3 3
phytoplankton to be 1.0(mm /mL = g/m )(Willen 1959, Nauwerck
1963).
Zooplankton
A Wildco Model 30-E28 conical style net (62-pm mesh net; D:L
ratio = 1:3) with 0.5-m opening (radius=0.25m) was used to collect,
where possible, two vertical zooplankton samples at each station.
Vertical tows were taken from 2m above the bottom to the surface (long
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tow) and from 20m or from the top of the metalimnion to the surface
(short tow). The short tow was analagous to an epilimnetic tow. In
some cruises, a third tow (medium tow) from the bottom of the
metalimnion to the surface was taken but was not analyzed in this
report. Filtration volume and towing efficiency were determined with
a Kahl flow meter (Model 00SWA200) mounted in the center of the net.
Filtration efficiency averaged 84.5% (range = 33-225), 83.OX (range =
34-277) and 80.6% (range = 28-152), respectively, for Lakes Erie,
Huron and Michigan for the entire sampling season. Following
collection, the net contents were quantitatively transferred to
one-liter sample bottles, narcotized with club soda and preserved with
5% formalin. Identification and enumeration of zooplankton follow
Gannon (1971) and Stemberger (1979) and were done by Mr. Tom Morse of
the Bionetics Corporation.
Raw counts were converted to number/mL by Bionetics, Inc. With
zooplankton, abundances were originally determined based on a sample
volume calculated from the depth of tow. All abundance values and
sample volumes were recalculated using the volume of water actually
filtered.
Abundances and dimensions (phytoplankton only) of each species
were entered into a Prime 750 computer using the INFO (Henco Software,
Inc., 100 Fifth Avenue, Waltham, Mass.) data management system.
Biovolumes were calculated only for phytoplankton and placed into
summaries for each sampling station containing density (cells/mL),
3
biovolume (jam /mL) and relative abundance of species. In
addition, each division was summarized by station. Summary
information is stored on magnetic tape and is available for further
analysis.
-------
6
RESULTS
PHYTOPLANKTON
Annual Abundance of Major Algal Groups
Species lists (Tables A1-A3) and summary tables of abundance
(Tables A7-A9) and biovolume (Tables A4-A6) are in Volume 2 - Data
Report.
LAKE ERIE
The phytoplankton assemblage was composed of 436 alga taxa
representing 105 genera from eight divisions: Bacillariophyta,
Chloromonadophyta, Chlorophyta, Chrysophyta, Cryptophyta, Cyanophyta.
Euglenophyta and Pyrrhophyta (Table 4). The Bacillariophyta possessed
the largest number of taxa (225) and biovolume (59.9% of the total),
while the second largest number (113) and biovolume (14.9%) were
observed for the Chlorophyta (Tables 4 and 5). Highest overall
densities were attained by the blue-green algae (89.6%). The average
density and biovolume for the sampling period were 40,055 cells/mL
(range = 27,120 to 49,151) and 1.36 mm^/L (range =0.63 to 1.80),
respectively, for all stations.
LAKE HURON
The phytoplankton assemblage was composed of 411 alga taxa
representing 90 genera from eight divisions. The Bacillariophyta
possessed the largest number of taxa (211) and biovolume (68.2% of the
total), while the second largest number of taxa (75) was observed for
the Chlorophyta (Table 4). The Cryptophyta attained the second
highest biovolume (8.29%) (Table 5). Highest overall densities were
-------
attained by the blue-green algae (89.5% of total). The average
density and biovolume for the sampling period were 19,147 cells/mL
3
(range = 11,700 to 30,085) and 0.38 mm /L (range = 0.14 to 0.75),
respectively, for all stations.
LAKE MICHIGAN
The phytoplankton assemblage was comprised of 452 taxa
representing 106 genera from eight divisions. The Bacillariophyta
possessed the largest number of taxa (221) and biovolume (56.41% of
the total), while the second largest number of taxa (88) were observed
for the Chlorophyta (Table 4). The Cryptophyta accounted for the
second highest biovolume (13.43%) (Table 5). Highest overall
densities were attained by the blue-green algae (92.2% of total). The
annual average density and biovolume were 29,839 cells/mL (range =
14,944 to 40,830) and 0.42 mm3/L (range = 0.17 to 0.58),
respectively, for all stations.
Seasonal Abundance and Distribution of Major Algal Groups
LAKE ERIE
Seasonally, abundance (cells/mL) increased from April to May
(Fig. 4a). In late June-early July, the density was still high
(49,151 cells/mL) but was followed by a general decrease till the end
of October when abundance increased to 43,966 cells/mL. A different
pattern emerged from the seasonal biovolume totals (Fig. 4b). Similar
to abundance, biovolume increased from April to early May. Unlike
abundance, biovolume decreased to late June-early July and then
generally increased to the end of October. The biovolume decrease to
late June-early July was due to a decline in the diatoms from 1,109 to
-------
251 cells/iuL. Abundance (cells/mL) was maintained by increases in the
smaller chrysophytes, cyanophytes and the cryptophytes.
Accounting for 70 to 85% of the phytoplankton community biovolume
(Fig. 5), the Bacillariophyta were dominant. By late June the diatoms
decreased and remained depressed to late August when they began to
increase in importance with the plankton community again. During the
summer period, the diatoms were succeeded by the Chrysophyta and
Pyrrhophyta in late June and the Chlorophyta in early August. The
Cyanophyta peaked in late August but were not major contributors to
the biomass of the phytoplankton community.
LAKE HURON
Seasonally, abundance was bimodal with two peaks (May-July and
mid-August). Abundance increased from April to May, was still
relatively high in early July (24,716 cells/mL), was lower in early
August, reached a second peak in mid-August (30,085 cells/mL) and
declined till late October. The second peak was caused by a bloom of
small Cyanophyta. A similar seasonal pattern for biovolume was
apparent (Fig. 4b) with the exception of the second peak which was
absent due to the small biovolume contribution of the abundant
blue-green algae.
The Bacillariophyta were dominant throughout the year but had a
bimodal distribution accounting for >75% (range = 75-84%) of the
plankton biovolume in April, May and late June-early July peak and 59%
of the phytoplankton biovolume in late October (Fig. 6). With the
decrease in the diatoms in early August, which was a month later than
in Lake Erie, a seasonal succession was evident with the Chrysophyta
peaking in early July, the Cryptophyta in early August, the Cyanophyta
-------
and Pyrrhophyta in late August followed by a second peak of the
Cryptophyta in mid-October. The Chlorophyta increased in importance
(¦^*19% of the total biovolume) by early August and maintained this
level to the end of the study in October.
LAKE MICHIGAN
Seasonally, abundance (cells/mL) increased from April to early
July (36,868 cells/mL), decreased to 14,944 cells/mL in early August
and increased to 48,305 cells/mL in late October (Fig. 4a). A
completely different biovolume pattern from the abundance pattern was
evident. The seasonal abundance pattern in Lake Michigan was
dissimilar to the biovolume pattern in late July and October due to
the large increase in Cyanophyta which did not contribute heavily to
the biomass of the phytoplankton because of their small size. The
seasonal biovolume pattern in Lake Michigan was similar to that of
Lake Huron's (Fig. 4b).
The Bacillariophyta were dominant accounting for as much as 73%
of the phytoplankton biovolume during the spring and autumn bloom
(Fig. 7). With the decrease in the diatoms in early and mid August,
which was a month later than in Lake Erie, a seasonal succession was
evident with the Chrysophyta peaking in early July, the Chlorophyta
and Cryptophyta in early August, the Pyrrhophyta and a second peak of
the Chrysophyta in late August, the Cyanophyta in mid-October, and a
second peak of the cryptophytes in late October.
Geographical Abundance and Distribution of Major Algal Groups
LAKE ERIE
The mean phytoplankton abundance for the sampling period was
-------
considerably greater at the three western stations (60,000-70.000
cells/mL) than in the rest of the lake (Fig. 8). This higher
abundance was caused mostly by the greater abundance of the Cyanophyta
in the western end of the lake. However, the Bacillariophyta,
Chlorophyta, Chrysophyta and Cryptophyta all possessed a general
pattern of decreasing abundance from west to east. The green algae
did have a curious increase in abundance at Stations 37 and 73 which
was not duplicated in any of the other algal groups. This increase at
Stations 37 and 73 was due to a bloom of green algae on the 6-8 August
and 22-23 August cruises. Density (cells/mL) on these dates ranged
from 1,546 to 3,992 cells/mL as compared to an average of 625 cells/tnL
for the other cruises.
Seasonally, the pattern of decreasing abundance from west to east
occurred on each cruise except on the 27 June-1 July and 21-24 October
cruises when the trend was reversed (Fig. 9) with abundance increasing
toward the eastern end of the lake. An increase in the Cyanophyta and
to a smaller degree in the Cryptophyta at the eastern end of the lake
accounted for this pattern.
LAKE HURON
The mean phytoplankton abundance for the sampling period
decreased from north to south to Station 15 (Fig. 10). Abundance
increased at Station 15 and then decreased slightly southward. Much
of this geographical distributional pattern was determined by the
abundance pattern of the Cyanophyta. However, the Chlorophyta and
Bacillariophyta had similar, although not as distinct, abundance
patterns as did the Cyanophyta from north to south. No distributional
pattern was apparent for the Cryptophyta while a general decrease in
-------
Chrysophyta abundance from north to south was evident with the
exception of Station 37. Chrysophyte abundance was drastically lower
at Station 37.
The seasonal geographical abundance patterns of the algal
divisions (Fig. 11) differed significantly from the total abundance
patterns (Fig. 10). Abundance was similar from the north to the south
but increased slightly from Station 15 southward on the 21-24 April
cruise. In the 6-8 May cruise, densities ranged from 10,000-15,000
cells/mL at northern stations (Stations 61 to 27) and increased to
-50,000 cells/mL at the southern stations in the 6-8 May cruise. In
early August, the distributional pattern had reversed with the higher
abundances occurring at the northern stations (Stations 61 and 54).
Higher abundances also occurred at the northern stations during the
cruise of 19-21 August.
The seasonal geographical abundance patterns were determined by
the abundance pattern of the Cyanophyta and to a lesser degree by the
diatoms, chrysophytes and unidentified flagellates in the April and
May cruises. The higher densities at the northern stations in early
August were predominantly caused by the Cyanophyta and to a lesser
degree by the greens and unidentified flagellates. The sharply higher
abundances at Stations 61, 45. 37 and 12 on the 19-21 August cruise
were due to higher abundances of the diatoms, green algae, blue green
algae and the unidentified flagellates.
LAKE MICHIGAN
The mean phytoplankton abundance for the sampling period
generally decreased from north to south with two small peaks at
Station 41 and at Station 6 at the most southern sampling point (Fig.
-------
12). This abundance pattern could be attributed mostly to Cyanophyta
and to a lesser degree to the Bacillariophyta. The Chlorophyta,
Chrysophyta and Cryptophyta had two abundance peaks on the north-south
transect: Station 64 and Stations 41 and 34.
Seasonally, the various cruises generally followed the same
north-south pattern (Fig. 13) as the mean annual phytoplankton
distribution. Abundances were high in the south at Station 6 and at
the northern stations (Stations 77, 64, 57) in April, May, early and
late August and late October. Only on the 12-15 October cruise did a
mflv-;mum at Station 6 not occur. On this cruise, two peaks did occur:
at Station 77, the northern most sampling point, and at Station 41.
Maximum densities were observed for Bacillariophyta, Chlorophyta,
Cyanophyta, Chrysophyta and the unidentifed flagellates at Station 77
for this cruise.
-------
13
Regional and Seasonal Trends in the Abundance of Common Taxa
LAKE ERIE
Common species (Table 6) were arbitrarily defined as those
possessing a relative abundance of >0.1% of total cells or >0.5% of
the total biovolume.
Cyanophyta
Anacystis marina Dr. & Daily
A. marina is widely distributed as plankton in fresh, brackish
and sometimes marine waters. It is rarely reported, probably because
it is easily overlooked (Humm and Wicks 1980). Cells range in size
from 0.5-2.0 jim in diameter. Because a number of varying shaped cells
were included as A, marina during identification, it is likely that
more than one species are being grouped together (Andresen 1985).
This was the dominant phytoplankter within the study area
representing 83% of the total algal abundance (cells/mL) but only
-»0.7% of the total algal biovolume. An average density of 33,167
cells/mL was observed for the study period with a maximum density of
141,208 cells/mL observed on 9 May 1985 at Station 55. Abundance was
generally higher at the western end of the lake with maximum densities
in May and June (Fig. 16a). Makarewicz (1985) reported this species
from the mouth of Niagara River and the Oswego River in Lake Ontario.
There are no other reports of this species in Lake Erie.
Anacystis montana f. minor Dr. & Daily
Humm and Wicks (1980) noted that A. montana was planktonic and
possessed a worldwide distribution in freshwater and in brackish water
-------
14
habitats. In Lake Ontario at the mouth of the Oswego River, this
species was observed to have a bimodal distribution with a peak in
late July and October (Makarewicz 1985). Seasonally in Lake Erie,
only one abundance peak was observed in mid-October (Fig. 14a).
Average density was 219 cells/mL with a maximum of 5,072 cells/mL on
19 October 1983 at Station 55 (Table 6).
Coccochloris peniocystis Kutz.
According to Humm and Wicks (1980), most reports of this species
are from freshwater, but occasionally it is reported from marine
habitats. It has a worldwide distribution. In Lake Erie in 1983,
this species was the third most abundant species (Table 6) reaching a
maximum density of 7,175 cells/mL on 27 July 1983 at Station 15.
Seasonally, distribution appeared bimodal with late June and September
peaks (Fig. 14b). Stoermer (1978) and Munawar and Munawar (1976) did
not include either _A. marina or C peniocystis in their lists of
abundant, common or "less common" species for Lake Erie.
Aphanizomenon flos-aquae (Lyngb.) Breb,
Ogawa and Carr (1969) and Stoermer (1978) reported A,, flos-aquae
to be abundant or occasionally abundant in Lake Erie. In 1970,
Munawar and Munawar (1976) observed A. flos-aquae to be a "most
common" species accounting for 14% (9-20%) and 8.5% of the mean
biomass volume in the western and central basins, respectively.
During August 1975 in the western basin, Gladish and Munawar (1980)
reported this species as contributing 12,8% of the total biomass.
Seasonally, A. flos-aquae did not appear throughout the lake
till late August and steadily increased in abundance to a mean of 437
-------
cells/mL in late October (Fig. 14c). A maximum abundance of 2,561
cells/mL was observed on 21 October at Station 57 (Table 6). The
3
biomass on this date and station was estimated to be 0.23 g/m ,
which was considerably lower than the maximum of approximately 1.6
3
g/m reported by Munawar and Munawar (1976) in 1970 for the
western basin. The percent of the total biovolume of this species for
this study was only 0.5%.
Coelosphaerium naegelianum Unger
Accounting for 0.59% of the total abundance (Table 6), this
species reached a maximum density of 5,890 cells/mL on 22 August at
Station 79 (mean abundance = 236 cells/mL). Seasonally, two abundance
peaks were observed in August and October (Fig. 14b). Geographically,
distribution was restricted to the western and central basins.
Merismopedia tenuissima Lemm.
Accounting for 0.83% of the total cells present in this study and
less than 0.01% of the total biovolume, the average density was 333
cells/mL with a maximum density of 15,544 cells/mL on 6 August at
Station 60. A mid-summer abundance peak at the western end of the
lake was evident (Fig. 17a).
Oscillatoria limnetica Lemm.
According to Huber-Pestalozzi (1938). this species is often
abundant in polluted waters. It is abundant in Lake Ontario, and its
peak abundance is in June and July (Stoermer et al. 1974) although
appreciable populations remain into the autumn (Munawar and Nauwerck
1971). Stoermer (1978) reported it as a common element of the Lake
-------
Erie plankton although Munawar and Munawar (1976) did not list it as a
common species (>5% of the total biomass) or less common species. This
difference may be related to Munawar's use of biomass as an indicator
of abundance. For example, in this study 0. limnetica represented
only 0.24% of the total biovolume but 1.15% of the total cells (Table
6). Seasonally, peak abundance was reached in late August (maximum
11,266 = cells/mL; Station 60) at the western end of the lake (Fig.
16c).
Oscillatoria subbrevis Schmid.
Although this species had a relatively high abundance (1.01% of
the total cells; 1.16% of the total biovolume), it was not commonly
found throughout the lake (Fig. 17b). The high relative abundance was
due to a single bloom (27,399 cells/mL) on one occassion (21 October)
at Station 57. Average density was 404 cells/mL.
Oscillatoria tenuis C.A. Ag.
This species experienced an isolated bloom of 5,081 cells/mL on
22 August at Station 55. In general, its geographical distribution
was restricted to the western end of the lake (Fig. 16b). Average
density was 80 cells/mL (Table 6).
Chlorophyta
Coelastrum microporum Nag.
Stoermer et al. (1974) reported this species as being widely
distributed in the Great Lakes but only reaching appreciable abundance
in eutrophic lakes. Taft and Taft (1971) reported it from western
Lake Erie. Stoermer (1978) reported it as occasionally abundant.
-------
In 1983, no obvious geographical pattern was observed.
Seasonally, it was not observed until early August but steadily
increased in abundance to the last sampling date in October (Fig.
14e). Maximum density was 2,291 cells/mL on 21 October at Station 18.
With an average density of 135 cells/mL, this was the dominant green
alga on a cells/mL basis (Table 6).
Cosmarium sp.
Hunawar and Munawar (1976) reported Cosmarium sp. as a common
species of the eastern basin representing 13.0% and 10.5% of the total
biovolume in the eastern basin in late August and September, A
3
maximum of — 0.4 g/m was observed in this bloom. Gladish and
Munawar (1980) reported a relative biomass of 5.6% and 6.3% in the 5
August and 2 September 1975 sampling in the western basin.
Although an average of only 3 cells/mL were observed for the
study period, Cosmarium sp. did account for 6.12% of the total
biovolume (Table 6) for the entire lake. Considering biomass, this
was the dominant chlorophyte. Mean maximum density was in early
August (Fig. 14d). Maximum biomass (71.4% of the total biomass) for a
3
single station was 1.0 g/m (Station 15, 6 August). Mean biomass
3
for all cruises for all stations ranged from 0.03 to 0.23 g/m ,
which was slightly lower than Munawar and Munawar's (1976) mean
biomass values for 1970. Although Munawar and Munawar (1976) observed
Cosmarium sp. as a common species only in the eastern basin, this
species was common in 1983 throughout all three basins.
Monoraphidium contortum (Thuret) Kom.-Legn.
With an average abundance of 82 cells/mL and a maximum density of
-------
744 cells/mL (Station 78, 9 May), this species accounted for 0.2% of
the total cells (Table 6). Seasonally, abundance was greatest in May
for the lake (Fig. 14e).
Mougeotia sp.
Stoermer (1978) reported this species as being occasionally
abundant, while Munawar and Munawar (1976) did not list it as a common
or less common species in 1970. In early July and late August (Fig.
14f) of 1983, two peaks in abundance were observed. Mean density was
only 14 cells/mL but because of the larger size of the cell, a mean
3
biomass of 12 mg/m (0.88% of the total biomass) (Table 6) was
3
observed with a maximum biomass of 200 mg/m on 22 August at
Station 37.
Pediastrum simplex v. duodenarium (Bail.) Rabh.
Two abundance peaks, mid-August and mid-October, were observed in
1983 (Fig. 14f) which corresponded well with Munawar and Munawar's
(1976) report of maximum mean percent of total biomass of 7.0% and
8.0% between 25-30 August 1970 and between 21-26 October 1970,
respectively, for the eastern basin. In the present study, mean
percent of the total biomass was 0.53 (Table 6) with a maximum of
11.0% and 6.9% at Station 18 (August, eastern basin) and at Station 79
(October, central basin). Biomass values ranged as high as 312
3
mg/m in the central basin (Station 79, October) with a mean of 7
3 3
mg/m for the lake. A maximum biomass of ~400 mg/m was
observed in October 1970 in the central basin (Munawar and Munawar
1976).
-------
Oocystis borgei Snow
Seasonally, a peak abundance in late August (Fig. 14d) was
observed. Average density and biomass were 16 cells/mL and 9,465
3 3 3
Mm /L (9 mg/m ). Maximum biomass was 87 mg/m at Station
37 on 6 August. This species contributed 0.88% of the total biomass
in 1983. Stoermer (1978) listed this species as a common element of
the plankton, while Munawar and Munawar (1976) did not report it as a
common (>5% of the total biomass) or less common species.
Scenedesmus ecornis (Ralfs) Chod.
This species has a seasonal and geographical distribution
predominately confined to the central basin (Fig. 17c). A maximum
3
population density of 2,193 cells/mL (300 mg/m ) was observed at
Station 37 on 6 August. Average density and biomass for the entire
3
lake were 112 cells/mL and 20 mg/m , respectively. This species
contributed the second largest amount (1.46%) to the total biomass of
the Chlorophyta (Table 6).
Staurastrum paradoxum Meyen
3
Mean seasonal biomass peaked in late August (85 mg/m ) and
3
late October (47 mg/m ). Mean biomass for the study period was 12
3
mg/m for the entire lake. S. paradoxum contributed 1.03% of
the total biomass (Table 6) and 2.6% of the biomass in the eastern
basin on 21 October. Stoermer (1978) listed this species as a common
element of the Lake Erie plankton. In 1970 this species accounted for
8.5% of the total biomass in the eastern basin between 21-26 October
(Munawar and Munawar 1976).
-------
20
Chrysophyta
Haptophyte sp.
Average density was 159 cells/mL with a maximum of 785 cells/mL
at Station 42 on 27 July. Seasonally, they are present from mid-May
to late August with mean peak abundance in late June (Fig. 15a). This
group contributed 0.40% of the total abundance.
Cryptophyta
Cryptomonas erosa Ehr.
C. erosa is widely distributed in the Great Lakes (Stoermer et
al. 1974), usually in low numbers. According to Huber-Pestalozzi
(1968), it is a eurytopic organism, occurring both in oligotrophic
lakes and often, in abundance, in eutrophic and slightly saline
habitats. Stoermer et al. (1974) listed it as a common element of the
Lake Erie plankton. Munawar and Munawar (1976) observed this species
to be abundant throughout the year in the western and central basins
3
reaching a biomass as high as ^2 g/m in May of 1970 in the
western basin. In the western basin, it contributed a maximum of 22%
of the biomass on the 3-7 July cruise. In the central basin, C.
erosa did contribute 34% of the biomass, but this was analagous to a
3
biomass value of -'600 mg/m . On 1 July 1975, Gladish and Munawar
(1980) reported this species to contribute 64.7% of the total
biovolume.
In the present study, geographical abundance was greatest in the
western basin and lowest in the eastern basin (Fig. 18a). Seasonally,
— 3
peak density varied geographically. Peak biomass (x = 600 mg/m )
occurred in the western basin (Stations 60,57,55) on 6 August. In the
central basin (Stations 42,73,37,78,79), mean maximum biomass was 67
-------
3
mg/m during the May-June period with populations near zero by
August. Average density and abundance were 31 cells/mL and 66
3
mg/m , respectively. For the lake, this species contributed 4.85%
of the total biomass. In the western basin, this species accounted
for 28.2% of the biomass on the 6 August cruise.
Chroomonas norstedtii Hansg.
Mean maximum seasonal abundance (119 cells/mL) was in early
August (Fig. 15b). Average density was 31 cells/mL with a maximum of
515 cells/mL at Station 57 on 6 August (Table 6).
Rhodomonas minuta v. nannoplanktica Skuj a
Stoermer (1978) listed this species as a common element of the
Lake Erie plankton. From June to late October of 1970, this species
was present in the eastern basin contributing as much as 37.5% of the
3
total biomass (—1.6 mg/m ) for a cruise. Seasonally, peak biomass
was observed in early June in the eastern basin. Although present in
the western and central basin, its contribution historically was never
greater than 23% of the biomass for a cruise with biomass not
3
exceeding 0.4 mg/m (Munawar and Munawar 1976).
3
In 1983 mean biomass for the entire lake was 33 mg/m with a
3
maximum biomass (143 mg/m ) at Station 79 on 9 May. Mean density
was 565 cells/mL. A maximum in May was observed, but abundance was
high through the summer (Fig. 15b). The high biomass in the eastern
basin reported by Munawar and Munawar (1976) was not observed in this
study. In fact, biomass is higher in the central basin than in the
eastern basin. This species contributed 2.41% of the total biomass
(Table 6).
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22
Pyrrhophyta
Ceratium hirundinella (O.F. Mull.) Schrank
3
In 1970 this species was abundant (maximum biomass —2 mg/m )
in all three basins with biomass reaching a peak in August with a
secondary peak in October in the eastern basin (Munawar and Munawar
1976). In 1975 this species accounted for 5.8% of the biomass on 12
August in the western basin (Gladish ad Munawar 1980). In 1983 C.
hirundinella reached a peak in early August (Fig. 15f). Mean biomass
3
and mean abundance were 92 mg/m and 1.4 cells/mL, respectively.
3
Maximum biomass (0.73 g/m ; 30.5% biomass for the day) occurred at
Station 37 on 6 August. For the entire lake, this species accounted
for 4.89% of the total biomass (Table 6).
Peridinium aciculiferum Lemm.
Munawar and Munawar (1976) observed this species to be a common
species (17% of biomass, central basin; 27% of biomass, eastern basin)
3
with a maximum biomass of ~0.2 g/m (central basin) and ^.1
3
g/m (eastern basin) in early May. Similarly in 1983, a peak in
_ 3
May was observed in the central basin (x = 64 mg/m ) and in the
3
eastern basin (S = 53 mg/m ). In May the percent contributing to
the biomass in the central and eastern basin was 3.8% and 14%,
respectively. For the entire lake, this species accounted for 0.76%
of the total biomass.
Bacillariophyta
Actinocyclus normanii f. subsalsa (Juhl.-Dannf.) Hust.
With an average density of 5.8 cells/mL and a maximum density of
-------
23
88 cells/mL at Station 55 on 6 August, this species contributed 2.65%
of the total biomass (Table 6). Two abundance peaks were observed in
early August and in mid-October (Fig. 15e).
Fragilaria capucina Desm.
High population densities of F. capucina are usually associated
with eutrophic or disturbed conditions in the Great Lakes (Stoermer
and Ladewski 1976). Hohn (1969) reported that it underwent a
significant increase in abundance in western Lake Erie during the
40's, 50's and 60's. Verduin (1964) mentioned F, capucina as
dominant in 1960-61, whereas Munawar and Munawar (1976) observed it to
be common but not dominant in 1970 in the eastern and central basins.
3
A maximum biomass of ^2.4 g/m (October) in the central basin and
3
~0.4 g/m (October and November) in the eastern basin was
reported.
In the present study, higher abundances were associated with
colder temperatures (Fig. 15d). Stoermer and Ladewski (1976) noted
that occurrences of F. capucina were at nearly all temperatures, but
high absolute and relative abundance was associated with higher
temperatures in Lake Michigan.
Geographically, the western basin had the highest biomass (21
3 3
mg/m ), followed by the eastern basin (12 mg/m ) and the
3
central basin (6 mg/m ). The maximum biomass observed was 0.13
3
g/m on 27 June at Station 60. Average density was 50 cells/mL
(Table 6).
Fragilaria crotonensis Kitton
This species can tolerate a wide range of ecological conditions
-------
(Stoermer and Tuchman 1979). Munawar and Munawar (1976) observed this
species to be abundant with decreasing maximum biomass from the
3 3
western (7.9 g/m ) to the central ("3.4 g/m ) to the eastern
3
(M.O g/m ) basin.
3
Average biomass in 1983 was 47 mg/m with a maximum of 0.27
3
g/m at Station 60 on 25 April. Abundances were greater in the
western end of the lake, and blooms tended to occur in April/May and
in October (Fig. 18b).
Melosira granulata (Ehr.) Ralfs
This species is usually considered a member of the classic
eutrophic diatom association (Hutchinson 1967). In 1970 distribution
of M. granulata was restricted to the western basin (Fig. 19) with a
3
bloom in early August. Maximum biomass was 0.3 g/m at Station 57
on 6 August.
Rhizosolenia sp.
Munawar and Munawar (1976) noted this organism as a less common
species of the western basin present in samples from late September to
December. In this study, a May bloom was observed (Fig. 15d). A
3
maximum biomass of 3.8 g/m was observed at Station 57 on 9 May.
Stephanodiscus alpinus Hus t.
Hohn (1969) reported £>. alpinus as being an important component
of the spring pulse in the western basin but being fairly abundant
throughout the year. Munawar and Munawar (1976) did not observe this
species in their 1970 collections.
In 1983 mean abundance and biomass were 9.5 cells/mL and 15
-------
3
mg/m , respectively. Seasonal distribution was bimodal with a
peak in early May and October with no obvious geographical pattern.
This species contributed 1.08% of the total biomass.
Stephanodiscus binderanus (Kutz.) Krieg
This species appears to be most abundant in eutrophic
environments during the cold season (Stoermer and Ladewski 1976).
Hohn (1969) reported it as having a major increase in abundance in the
50's and 60's. In 1970 Munawar and Munawar (1976) observed M.
binderana (= . binderanus ) to be a common species (>5% of the total
biomass) in the western and central basins in the April cruise. A
3
maximum biomass of ~0.5 g/m was observed in the western basin.
In 1983 the mean maximum abundance of J>. binderanus peaked in
May and in October (Fig. 15c). Geographically, abundance decreased
from west (101 cells/mL; Station 60) to east (3.4 cells/mL; Station
3
9). Mean biomass in the western basin was 26 mg/m with a maximum
3
of 0.23 g/m at Station 60 on 9 May.
Stephanodiscus niagarae Ehr.
In the Great Lakes, this species is abundant in naturally
eutrophic areas (Stoermer and Yang 1970). Munawar and Munawar (1976)
observed it in the autumn pulse to have a maximum biomass of vO.6, 2.3
3
and l.A g/m in the western, central and eastern basins,
respectively. This one species accounted for 54-74% of the total
biomass in the autumn in the central basin and 64-80% of the biomass
in November and December in the eastern basin.
In the present study, mean biomass for all dates for the western,
3 3
central and eastern basins was 61 mg/m , 0.9 g/m and 0.29
-------
3 3
g/m , respectively. A maximum biomass of 3.1 g/m was
recorded at Station 42 on 19 October. Mean biomass for the central
3
basin on 21 October was 1.8 g/m which accounted for 76% of the
total biomass. A minor peak in abundance occurred in May with a major
bloom in October (Fig. 15c). For the lake, this species contributed
37% of the biomass making it the dominant species on a biomass basis
(Table 6).
Tabellaria flocculosa (Roth) Kutz.
Tabellaria fenestrata was a dominant species prior to 1950 but
not in 1960-61 (Verduin 1964). Similarly, Munawar and Munawar (1976)
observed T. fenestrata not to be important in the 1970 collections.
Neither worker mentioned T. flocculosa. Differing taxonomic
concepts of the Tabellaria fenestrata - T. flocculosa complex do
occur in the literature (e.g. Koppen 1975). Perhaps investigators
have been reporting the same entity and simply using differing
systematics.
In the present study, although T. fenestrata was observed, T.
flocculosa was more important contributing 3.8% of the total biomass.
3 3
Mean biomass was 51 mg/m with the western (103 mg/m ) and
3
eastern (65 mg/m ) basins being greater than the central (11
3
mg/m ) basin. Seasonally, a bloom occurred in late April and May
(Fig. 18c).
-------
27
LAKE HURON
Abundant species
possessing a relative
of the total biovolume.
Cyanophyta
Anacystis marina Dr. & Daily
A. marina is widely distributed as plankton in fresh, brackish
and sometimes marine waters. It is rarely reported, probably because
it is easily overlooked (Humm and Wicks 1980). Cells range in size
from 0.5-2.0 jim in diameter. Because a number of varying shaped cells
were included as A. marina during identification, it is likely that
more than one species is being grouped together (Andresen 1985).
This was the dominant phytoplankter within the study area
representing 81% of the total algal abundance (cells/mL) but only 1.9%
3
of the total algal biovolume (8.5 mg/m ). An average density of
18,011 cells/mL was observed for the study period with a maximum
3
density of 55,518 cells/mL (0.23 mg/m ) observed on 19 August at
Station 61 (Table 7). Abundance was generally higher at the northern
end of the lake with maximum densities in May and August (Fig. 20a).
Makarewicz (1985) reported this species from the mouth of Niagara
River and the Oswego River in Lake Ontario and from Lake Erie (This
Report). There are no other reports of this species in Lake Huron,
Anacystis montana f. minor Dr. & Daily
Humm and Wicks (1980) noted that A. montana was planktonic and
possessed a worldwide distribution in freshwater and in brackish water
(Table 7) were arbitrarily defined as those
abundance of >0.1% of the total cells or >0.5%
-------
habitats. In Lake Ontario at the mouth of the Oswego River, this
species was observed to have a bimodal distribution with a peak in
late July and October (Makarewicz 1985). Seasonally in Lake Erie,
only one abundance peak was observed in mid-October (This Study).
Munawar and Munawar (1982) and Stoermer and Kreis (1980) did not
report this species. In Lake Huron in 1983, a bimodal pattern was
observed, except the spring peak was in May (Fig. 20e). Average
density was 380 cells/mL with a maximum of 2,556 cells/mL on 16
October 1983 at Station 12 (Table 7).
Anacystis thermalis (Menegh.) Dr. & Daily
Stoermer and Ladewski (1976) reported this species as being a
common element of phytoplankton assemblages in mesotrophic to
eutrophic lakes. Munawar and Munawar (1982) did not list A.
thermalis as a common species in their 1971 samples. However, this
species is often reported as various species of Chroococcus (Stoermer
and Ladewski 1976). Munawar and Munawar (1982) observed three species
of Chroococcus that were common (>5% of the biomass). Stoermer (1978)
listed this species as present only in minor quantities in Lake Huron.
In 1974 maximum abundance was reached in October. Mean abundance in
southern Lake Huron was 12 cells/mL.
3
With an average density of 17 cells/mL (2.4 mg/m ), this
species contributed only 0.08% of the relative abundance and 0.54% of
the total biomass for the lake (Table 7). Seasonal abundance was
highest in October (Fig. 20c). No obvious geographical north-south
pattern was obvious.
-------
Coccochloria elabans Dr. & Daily
Munawar and Munawar (1982) did not list this species as a common
species (>5%) in their 1971 samples. Stoermer and Kreis (1980) listed
a Coccochloris sp. as having a mean density of 0.31 cell/ml with a
maximum of 50.3 cells/ml. In 1983 average density was 38 cells/mL
accounting for 0.17% of the total cells (Table 7). A maximum
abundance of 434 cells/mL was observed on 4 August at Station 61.
Seasonal abundance was bimodal with a spring pulse in May and a second
summer maximum during August. This seasonal pattern was present at
most stations (Fig. 23c).
Coccochloris peniocystis Kutz.
According to Humm and Wicks (1980), most reports of this species
are from freshwater, but occasionally it is reported from marine
habitats. It has a worldwide distribution. In Lake Erie in 1983,
this species was the third most abundant species (This Study). In
Lake Huron in 1983, C. peniocystis was the second most abundant
species (Table 7) with a maximum density of 7,929 cells/mL (15
3
mg/m ) on 19 August 1983 at Station 9. Seasonally, distribution
appeared unimodal with a late August maximum extending into October
(Fig. 20b).
Coelosphaerium naegelianum Unger
Munawar and Munawar (1982) did not list this species as a common
species in 1971. Also, Stoermer and Kreis (1980) did not observe this
species in 1974. Accounting for 0.33Z of the total abundance (Table
7), this species reached a maximum density of 900 cells/mL on 16
October at Station 45 (mean abundance =74 cells/mL). Seasonally, an
-------
abundance peak was observed in October and perhaps in August (Fig.
20c). Geographically, abundance was higher in the northern portion of
Lake Huron (Stations 61,54,45).
Oscillatoria limnetica Lemm.
According to Huber-Pestalozzi (1938), this species is often
abundant in polluted waters. Munawar and Munawar (1982) did not
report this species as common in 1971, while Stoermer and Kreis (1980)
observed mean densities of only 0.08 cell/mL representing 0.002% of
the population. In Lake Huron, it contributed only 0.06% of the total
biovolume and 0.39% of the total cells (Table 7). Seasonally, peak
abundance was reached in spring (maximum 974 cells/mL; Station 15)
(Fig. 23b), No obvious geographical pattern existed (Fig. 23b)
although mean station abundance was higher at Stations 9 and 15 (x =
151 cells/mL). The discharge of Saginaw Bay into Lake Huron (Schelske
et al. 1974, Stoermer and Theriot 1985) may have influenced this
abundance pattern. Blue-greens, including 0. limnetica, contributed
42,7% of the phytoplankton assemblage of Saginaw Bay in 1980.
Gomphosphaeria lacustris Chod.
Unlike most species of blue-green algae, G. lacustris seems to
be common in the offshore waters of the upper Great Lakes
(Vollenweider et al. 1974, Stoermer and Ladewski 1976). Stoermer
(1978) listed this species as being occasionally abundant. Munawar
and Munawar (1982) reported it as a common species (>5% of the
biomass) in the fall plankton assemblage in 1971. In 1974 it was
quite abundant (91 cells/mL; 4.5% of the population) in southern Lake
Huron (Stoermer and Kreis 1980).
-------
In 1983 average density and biomass were 38 cells/mL and 0.2
3
mg/m , respectively. Maximum abundance encountered was 920
cells/mL at Station 9 during May and 491 cells/mL at Station 61 during
mid-August. Mean abundance without the maximum values of Stations 9
and 61 was only 5.A cells/mL.
Chrysophyta
Chrysophaere11a longispina Laut. emend. Nich.
This species is usually a minor component of phytoplankton
assemblages in oligotrophic to mesotrophic lakes and small ponds
(Huber-Pestalozzi 1941). Stoermer (1978) listed this species as
occasionally abundant. Stoermer and Kreis (1980) observed small
isolated populations in samples from early May through June in
southern Lake Huron. But in August and October, abundance was high
along the Michigan coast and at mid-lake stations in southern Lake
Huron (maximum *425 cells/mL). Mean density for southern Lake Huron
in 1974 was 40 cells/mL.
In the present study, abundance was near zero to mid-August and
steadily increased into October (Fig. 22a). Average abundance for the
3
lake was 13 cells/mL (5.3 mg/m ) (Table 7). Maximum density
observed was 74 cells/mL at Station 6 in southern Lake Huron on 16
October. Mean density for stations (27,15,12,9,6) in southern Lake
Huron in October was 39 cells/mL.
Dinobryon cylindricum Imhof
This was not a common species (>5% of the biomass) in 1971
(Munawar and Munawar 1982). In 1974 Stoermer and Kreis (1980)
observed a density of 0.04 cell/mL representing only 0.005% of the
-------
population in southern Lake Huron at 5m.
In 1983 mean abundance was 16 cells/mL. Mean biomaes was 5.8
3
mg/m representing 1.3% of the total biomass. Seasonally,
populations increased into May and decreased to near zero by August
(Fig. 22b). Mean density for all cruises in southern Lake Huron was
12.3 cells/mL.
Dinobryon divergens Imhof
This species is apparently widely distributed and may occur in
waters of significantly different trophic levels (Stoermer and Kreis
1980). In 1973 Munawar and Munawar (1982) reported this species as a
common species in the spring and fall. In 197A densities of 200
cells/mL were reached in the extreme southern end of Lake Huron.
During Stoermer and Kreis's (1980) study, mean abundance was 14.6
cells/mL representing 1.05% of the population.
In 1983 mean abundance for the lake was 16.1 cells/mL
3
representing 0.1% of the total cells. Mean biomass was A.7 mg/m
accounting for 1,05% of the total biomass (Table 7). Geographically,
mean densities were similar from north to south. A peak in mean
abundance occurred in early July (Table 22b).
Dinobryon sociale var. americanum (Brunnth.) Bachm.
In southern Lake Huron in 1974, mean abundance was 0.094 cell/mL
with a maximum density of 12.6 cells/mL. In the present study, mean
3
density and biomass were 49 cells/mL and 6.0 mg/m , respectively.
The species constituted 1.34% of the total biomass. Mean densities
for the study were higher in the north (Stations 61 and 54; x = 65
cells/mL) as compared to the rest of the lake (x = 22 cells/mL).
-------
Haptophyte sp.
Mean density was 168 cells/mL representing 0.75% of the total
cells. Seasonally, a single major abundance peak occurred from just
south of Saginaw Bay northward. South of Saginaw Bay, abundance was
much lower and a May and August peak was evident (Fig. 24b). A
maximum abundance of 859 cells/mL was observed at Station 32 on 2
July.
Cryptophyta
Cryptomonas erosa Ehr. and Cryptomonas erosa var. reflexa Marss.
C. erosa is widely distributed in the Great Lakes (Stoermer et
al. 1974), usually in low numbers. According to Huber-Pestalozzi
(1968), it is a eurytopic organism, occurring both in oligotrophic
lakes and often in abundance in eutrophic and slightly saline
habitats.
In 1971 it was a common species (>5% of biomass) in the spring,
summer and fall (Munawar and Munawar 1982). During June C. erosa and
Cryptomonas sp. made up 75% of the biomass (Vollenweider et al. 1974).
Stoermer and Kreis (1980) reported it as a minor constituent of the
phytoplankton community with an average density of 0.027 cell/mL (
0.001% of the population) in southern Lake Huron in 1974.
In 1983 C. erosa and C. erosa v. reflexa had an average density
3
of 6.7 cells/mL and mean biomass of 12.7 mg/m . Although they
contributed only 0.03% of the total abundance, they represented 2.8%
of the total biomass (Table 6). Seasonally, mean abundance decreased
from April to early July, peaked in August, decreased slightly in
mid-August and increased slightly into October (Fig. 20f).
-------
Cryptomonas pyrenoidifera Geitl.
Both Stoermer and Kreis (1980) and Manawar and Munawar (1982)
observed Cryptomonas sp. in 1971 and 1974 but did not list C
pyrenoidifera. C. ovata was reported as accounting for 0.46% of the
phytoplankton population in 1974 by Stoermer and Kreis (1980).
In 1983 ovata was less than 0.1% of the total cells. The
3
average biomass of J3, pyrenoidifera was 3.5 mg/m constituting
0.78% of the total biomass (Table 7). Maximum mean populations were
reached in the early spring (Fig. 21a). No north-south gradient or
geographical pattern waB observed.
Rhodomonas minuta var. nannop1anktica Skuj a
Munawar and Munawar (1982) reported R. minuta as abundant (>5%
of the biomass) in the spring, summer and fall of 1971. Between R.
minuta v. nannoplanktica and R. minuta , Stoermer and Kreis (1980)
observed the variety nannoplanktica to be the prevalent form in
southern Huron in 1974. Average density in southern Lake Huron was
8.2 cells/mL (0.77% of the population) with a maximum of 54 cells/mL.
It was present at most stations throughout the year but appeared to be
most abundant during June at offshore stations.
In the present study. R. minuta v. nannop1anktica was more
prevalent than R. minuta. Mean density was 204 cells/mL (0.92% of
3
the total cells) with mean biomass being 15.2 mg/m (3.4% of the
total biomass). Maximum abundance was 311 cells/mL in early May at
Station 15. Seasonally, this species was abundant throughout the lake
from April till October (Fig. 20d).
-------
Pyrrhophyta
Ceratium hirundinella (O.F. Mull.) Schrank
C, hirundinella was a common species (>5% of the biomass) in
the summer of 1971 (Munawar and Munawar 1982). Stoermer and Kreis
(1980) reported it as having an average density of only 0.16 cell/mL
(0.009% of the population) for the 5-m depth in southern Lake Huron.
A maximum of 6.3 cells/mL was reported.
Similarly in 1983, mean abundance was 0.11 cell/mL ( 0.001% of
the total cells) with the mean biomass being 5.6 mg/m (1.3% of
the total biomass) (Table 7). Although this species occurred only at
two stations during the 19-21 August cruise, average contribution to
the phytoplankton biomass for the cruise was 7.3%.
Bacillariophyta
Asterionella formosa Hass.
A common species (>5% of the biomass) in the spring, summer and
fall of 1971 (Munawar and Munawar 1982), this species is considered a
common element of the plankton assemblage (Stoermer 1978). In
Stoermer and Kreis's (1980) 1974 work on southern Lake Huron,
abundance was generally highest at the nearshore stations and at the
Saginaw Bay interface. In mid-July abundance was reduced except at
stations in the southern part of Lake Huron (abundance ~100 cells/mL).
Abundance in October and November of 1974 generally increased from the
summer. Mean abundance was 38.5 cells/mL (2.9% of the population)
with a mflT-jp1"!" of 394 cells/mL. In 1980-81, A. formosa represented
6.7% of the total diatoms in Lake Huron. Abundance was greatest
during the spring. Lowest abundance regularly occurred in September
except near the Straits of Mackinac (Stevenson 1985).
-------
In the present study, mean density and biomass were 9.7 cells/mL
(0.04% of the total cells) and 3.0 mg/m^ (0.66% of the total
biomass). Maximum density was 103 cells/mL in July at Station 61.
Seasonally, maximum density was observed in the early July sample with
abundance greatly higher in the northern part of the lake (Fig. 23a).
Cyclotella comensis Grun.
Munawar and Munawar (1982) did not report this species as a
common species during 1971. They did list C. michiganiana, which can
be difficult to distinguish from small C. comensis (Stevenson 1985).
Stoermer and Kreis (1980) reported that the high abundances attained
in southern Lake Huron in 197A were unprecedented. In August C.
comensis was in bloom quantities at most stations. Mean density was
150 cells/mL (8.6% of the population with a maximum of 1508 cells/mL).
Stevenson (1985) reported a mean relative abundance of 9.7% of the
total diatoms.
In 1983 mean abundance increased to early August and decreased
slightly into October (Fig. 21b). Abundances were greatest at the
northern (Station 61, 45 cells/mL) and southern (Station 6, 82
cells/mL) ends of the lake as compared to the rest of the lake (x = 27
cells/mL). Mean abundance was 49 cells/mL with a maximum of 385
cells/mL in early August at Station 6. On a cells/mL basis, this was
the dominant diatom representing 0.29% of the total cells (Table 7)
and 24.9% of the total diatoms.
Cyclotella comta Ehr. (Kutz.)
A common species in the spring, summer and fall of 1971 (Munawar
and Munawar 1982), this species is a member of the classic
-------
oligotrophic Cyclotella association (Hutchinson 1967). In 1974
average density was 4.7 cells/mL (0.37% of the population) with a
maximum of 31.4 cells/mL. Highest overall abundance occurred in
August and mid-October in southern Lake Huron (Stoermer and Kreis
1980).
In 1983 mean abundance was 6.4 cells/mL (0.03% of the
3
population). Mean biomass was 17.7 mg/m (3.94% of the total
biomass) (Table 7). Abundance was higher (4.4 cells/mL) north of
Saginaw Bay than south of it (1.5 cells/mL). Highest abundance
occurred in August and October (Fig. 21b).
Cyclotella kuetzingiana var. planetophora Fricke
Munawar and Munawar (1982) reported C. kuetzingiana as a common
(>5% of the biomass) element of the summer plankton assemblage.
Stoermer and Kreis (1980) reported C. kuetzingiana as having a mean
density of 0.02 cell/mL (0.003% of the population) with a maximum of
2.1 cells/mL in southern Lake Huron at 5 m.
In 1983 mean abundance was low throughout the spring and summer
and increased to 50 cells/mL in October. Average density was 16.5
3
cells/mL. Mean biomass was 5.0 mg/m representing 1.1% of the
total biomass. In October this species contributed 6.1% of the
biomass.
Cyclotella ocellata Pant.
In 1971 this species was a common element (>5% of the biomass) of
the spring« summer and fall assemblage (Munawar and Munawar 1982).
This species is an important component of phytoplankton assemblages in
northern Lake Huron (Schelske et al. 1974, Schelske et al. 1976) and
-------
38
is generally abundant in areas of the Great Lakes which have not
undergone significant eutrophication (Stoermer and Kreis 1980).
During 197A mean abundance was 24.1 cells/mL (2.4% of the
population) with a maximum of 169.6 cells/mL. Abundance was generally
high in May and June and reduced in August. In 1980 it represented
5.2% of the total diatom abundance (Stevenson 1985).
During the present study, mean abundance increased into early
July, was low in August and increased into October (Fig. 21c). Mean
abundance and biomass were 29.9 cells/mL (0.13% of the total cells)
3
and 2.3 mg/m (0.52% of the total biomass), respectively (Table
7). A maximum abundance of 254 cells/mL occurred at Station 61 in
early July. Mean abundance was high (42 cells/mL) at the most
northerly station (Station 61) as compared to the rest of the lake (x
= 18.2 cells/mL). 0. ocellata represented 8.7% of the total diatom
abundance.
Cymatopleura solea var. apiculata (W. Sm.) Ralfs
Stoermer and Kreis (1980) reported an average abundance of 0.027
cell/mL (0.002% of the population) with a maximum of 2.9 cells/mL. In
1983 density was low (0.2 cell/mL), but biomass was relatively high
3
(13.4 mg/m , 3.0% of the total biomass).
Fragilaria crotonensis Kitton
This species was a common element (>5% of the biomass) in the
spring, summer and fall in 1971 (Munawar and Munawar 1982). In 1974
seasonal minimal abundance occurred in August in southern Lake Huron.
Average density was 116 cells/mL representing 7.6% of the population.
Maximum abundance was 1898 cells/mL (Stoermer and Kreis 1980).
-------
Stevenson (1985) reported £ crotonensis to represent 18.8% of the
diatom abundance in 1980 and to be one of the two most common diatoms.
In the present study, F. crotonensis averaged 27.6 cells/mL
(0.12% of the total cells) which represented a biomass of 22.9
3
mg/ra (5.1% of the biomass) (Table 7). For the lake, a May
maximum extending into July, an August minimum and a second increase
into October were evident (Fig. 22d). Similar to Stevenson's (1985)
observations, a difference in maxima between regions was observed.
South of Saginaw Bay, the spring bloom occurred in early May and
collapsed by July. North of Saginaw Bay, a maximum in abundance was
not observed till early July. F. crotonensis represented 9.7% of the
total diatom abundance in 1983.
Fragilaria intermedia var. fallax (Grun.) Stoerm. & Yang
Stoermer and Yang (1970) reported this species to reach its
maximum relative abundance in the spring in Lake Michigan. In Lake
Huron in 1974, a mean abundance of 3.2 cells/mL (0.23% of the
population) with a maximum of 279 cells/mL was observed.
In 1983 a mean abundance and biomass of 8.2 cells/mL and 5
3
mg/m , respectively, were observed (Table 7), They represented
1.1% of the phytoplankton biomass of the lake. Maximum abundance was
60 cells/mL in May at Station 37. The seasonal maximum occurred in
spring with higher abundances at the mid-lake stations (37,32,27)
(Fig. 24a). As with F. crotonensis, the spring bloom occurred
earlier south of Saginaw Bay.
Melosira islandica 0. Mull.
This species is a common cold season dominant in boreal and
-------
alpine lakes worldwide (Stoermer and Kreis 1980). Munawar and Munawar
(1982) noted this species as a common element of the spring and summer
plankton. It displayed a spring bloom in most of southern Lake Huron
during 1974 (Stoermer and Kreis 1980) and throughout the lake in 1980
(Stevenson 1985) representing 2.8% of the diatom abundance. In 1974
average abundance was 15.2 cells/mL (0.97% of the population) with a
maximum of 813 cells/mL.
In the present study, a spring bloom was also observed (Pig.
3
22c). Mean density and biomass were 12.7 cells/mL and 17 mg/m ,
respectively. This species represented 3.8% of the total biomass for
the entire sampling area. Maximum abundance was 90 cells/mL at
Station 9 in May.
Rhizosolenia sp.
Munawar and Munawar (1982) noted R. eriensis as a common element
of the spring assemblage. Both R. eriensis and R. gracilis were
observed in 1974 by Stoermer and Kreis (1980). Combined mean
abundance for these species was 49.7 cells/mL representing 4.4% of the
population.
In 1983 abundance was low in April and August-October. In May
and July, abundance was high (40 cells/mL; Fig. 21f). Mean abundance
3
was 17.2 cells/mL with a biomass of 127 mg/m . This represented
28.4% of the total biomass and made this the dominant species on a
biomass basis.
Stephanodiscus niagarae Ehr. and £ transilvanicus Pant.
While a common element of the spring plankton in 1971 (Munawar
and Munawar 1982), it was not in 1974 (Stoermer and Kreis 1980). In
-------
1974 S. hantzschii and j|. minutus were the prevalent species of
Stephanodiscue . With a mean abundance of 0.12 cell/mL, J3 niagarae
accounted for only 0.006% of the population.
In 1983 £3. niagarae and S. transilvanicus were the prevalent
species with a combined abundance of 1.2 cells/mL accounting for
0.005% of the total cells but 3.3% of the total biomass (14.5
3
mg/m ) (Table 7). Seasonally, a peak in abundance in the spring
was observed for S. transilvanicus. A fall peak and a small
abundance increase in May were noted for J3. niagarae (Fig. 21d) .
Tabellaria flocculosa (Roth) Kutz. and T. flocculosa var.
linearis Koppen
Munawar and Munawar (1982) reported this species as a dominant in
Lake Huron. In 1974 T. flocculosa v. linearis was more prevalent (x
= 28.8 cells/mL, 2.1% of the population) as compared to T. flocculosa
(1.1 cells/mL, 0.09% of the population). Stevenson (1985) reported
that although the seasonal abundance pattern was variable from region
to region in 1980, it bloomed in most areaa of the lake in spring.
Similar seasonal patterns were observed in the 1974 study of southern
Lake Huron (Stoermer and Kreis 1980).
In 1983 the mean abundance was high in the spring and was low
during the rest of the sampling period (Fig. 21e). T. flocculosa
(20.3 cells/mL) was more abundant than T. flocculosa v. linearis (1.4
cells/mL). T. flocculosa contributed 13.5% of the total biomass
making it the second most dominant species on a biomass basis (Table
7). No obvious geographical pattern was observed.
-------
42
LAKE MICHIGAN
Abundant species (Table 8) were arbitrarily defined as those
possessing a relative abundance of >0.1% of total cells or >0.5% of
the total biovolume.
Cyanophyta
Anacystis marina Dr. & Daily
A. marina is widely distributed as plankton in fresh, brackish
and sometimes marine waters. It is rarely reported, probably because
it is easily overlooked (Humm and Wicks 1980). Cells range in size
from 0.5-2.0 >im in diameter. Because a number of varying shaped cells
were included as A. marina during our identification, it is possible
that more than one species is being grouped together (Andresen 1985).
This was the dominant phytoplankter within the study area
representing 84.6% of the total algal abundance (cells/mL) but only
3
1.6% of the total algal biovolume (6.3 mg/m ). An average density
of 23,607 cells/mL was observed for the study period with a maximum
density of 120,019 cells/mL observed on 26 October at Station 77
(Table 8). Mean station abundance was higher (36,315 cells/mL) in the
north (Stations 77,64,57) as compared to the rest of the lake (18,850
cells/mL). Differences in seasonal distribution were also evident.
The entire offshore region experienced a maximum in October. A second
weaker abundance peak was present in the spring or July at most
stations (Fig. 28a). Makarewicz (1985) reported this species from the
mouth of Niagara River and the Oswego River in Lake Ontario, and from
Lake Erie and Huron (This Report). There are no other reports of this
species in Lake Michigan.
-------
43
Anacystis montana f. minor Dr. & Daily
Hntnm and Wicks (1980) noted that A. montana was planktonic and
possessed a worldwide distribution in freshwater and in brackish water
habitats. In Lake Ontario at the mouth of the Oswego River, this
species was observed to have a bimodal distribution with a peak in
late July and October (Makarewicz 1985). Seasonally in Lake Erie,
only one abundance peak was observed in mid-October (This Study). In
Lake Huron in 1983, a bimodal pattern was observed with the spring
peak in May (Fig. 20e). Similar to Lake Erie, only one abundance peak
was observed in Lake Michigan in October of 1983 (Fig, 25a). Mean
abundance was 451 cells/mL with a maximum of 3,289 cells/mL (Table 8).
This species has not been reported before in Lake Michigan.
Anacystis thermalis (Menegh.) Dr. & Daily
Stoermer and Ladewski (1976) reported this species as being a
common element of phytoplankton assemblages in mesotrophic to
eutrophic lakes. In the 60*s, abundance of A. thermalis increased
greatly in southern Lake Michigan. Maximum abundance was 460 cells/mL
in 1971 (Stoermer and Ladewski 1976). From Rockwell et al.'s (1980)
report on southern Lake Michigan, an average density of 397 and 781
cells/mL in August and in September of 1977 can be computed. Stoermer
(1978) listed this species as a common element of the plankton
assemblage.
In the present study, mean maximum abundance occurred in early
October (Fig. 25a). Mean abundance was greater (602 cells/mL) in
southern Lake Michigan (Stations 26 and 27 southward) than in the
north (325 cells/mL). Average density for the lake was 451 cells/mL
-------
44
(1.6% of the total cells) with a maximum of 3,289 cells/mL at Station
3
27 on 12 October. Mean biomass was 3.0 mg/m .
Coccochloris peniocystis (Kutz.)Dr. & Daily
There appears to be no other previous reports of this species in
Lake Michigan. According to Humm and Wicks (1980), most reports of
this species are from freshwater, but occasionally it is reported from
marine habitats. In Lake Erie in 1983, this species was the third
most abundant species (This Study); in Lake Huron in 1983, it was the
second most abundant species; and in Lake Michigan in 1983, it was the
second most prevalent species (Table 8).
Mean abundance and biomass were 1,340 cells/mL (4.8% of the total
3
cells) and 3.0 mg/m (0.77% of the total biomass). Populations
appeared to build up during the spring and summer reaching a peak in
mid-August and then declined into October (Fig. 25a). Abundances were
higher (x = 2,025 cells/mL) at the far northern stations (57,64,77)
than in the rest of the lake (960 cells/mL).
Coelosphaerium naegelianum linger
Parkos et al. (1969) provided abundance estimates for
Coelosphaerium sp. for different regions of the lake in 1967. Average
density for early and late October was 194 cells/mL. Rockwell et al.
(1980) reported a mean density of 13.5 cells/mL for Coelosphaerium
kuetzingianum in late August.
In 1983 average density was 39 cells/mL with a maximum abundance
of 1,227 cells/mL on 4 July at Station 64. Distribution was generally
limited to the far northern portion of the lake (Stations 77 and 64)
and one occurrence at Station 11 at the southern end of the lake.
-------
Seasonally, two mean abundance peaks, July and October, were observed
(Fig. 25b).
Oscillatoria agardhii Gom.
During the spring of 1963, Oscillatoria sp. was observed by
Stoermer and Kopczynska (1967a) at densities less than 100 cells/mL.
In 1983 0. agardhii had a mean abundance and biomass of 14.2 cells/mL
3
and 2.8 mg/m , respectively. Maximum abundance was 344 cells/mL
at Station 64 on 5 May. Seasonally, population density waB high in
April and May, had collapsed by July and stayed low the rest of the
sampling period (Fig. 25b). ThiB species was observed at the far
northern end of the lake (Stations 77 and 64) and at mid-lake Stations
23 and 27 only.
Oscillatoria limnetica Lemm.
Ahlstrom (1936) and Stoermer and Kopczynska (1967a) listed 0.
mougeotii as the only species of the genus at all abundant in their
collections. Stoermer and Ladewski (1976) reported that this species
has increased in abundance in Lake Michigan. Rockwell et al. (1980)
reported that 0. limnetica was common throughout the basin in April
and June and was especially abundant in September of 1977 at certain
stations.
In the present study, an average density and biomass of 139
3
cells/mL (6.5% of the total cells) and 1.0 mg/m (0.26% of the
total biomass) were observed, respectively. Mean maximum abundance
occurred in July (Fig. 25c). However, differences in maximum
abundance were observed within regions of the lake. Peaks in ma-g-itmnn
abundance were much greater at mid-lake stations (23.27,34,41) than
-------
46
at the northern and southern stations (Fig 27c).
Pyrrhophyta
Ceratium hirundinella (O.F. Mull.) Schrank
Ahlstrom (1936) noted that in his collections C. hirundinella
did not become abundant until July and later. In 1967, 1.1 cells/mL
for the lake were observed (Parkos et al. 1969). Stoermer and
Ladewski (1976) reported low abundances (maximum =3.5 cells/mL) in
southern Lake Michigan in 1971.
In 1983 average density was low (0.22 cell/mL), but mean biomass
3
was high (21 mg/m ) representing 5.4% of the total biomass (Table
8). Seasonally, a population maximum of C. hirundinella occurred in
August. This species was observed only in the southern portion of the
lake (Stations 6,11,18,23,27).
Chlorophyta
Cosmarium sp.
In October of 1967, this genus attained a density of 0.6 cell/mL
in the northern lake region (Parkos et al. 1969). In 1983 this genus
3
had a mean density and biomass of 0.39 cell/mL and 7.0 mg/m ,
respectively (Table 8). It contributed 1.79% of the total biomass.
In April abundance was low (0.16 cells/mL) but increased to 1.6
cells/mL in May. This abundance was maintained into August. In
October the organism was not observed.
Monoraphidium contortum (Thur.) Kom.-Legn.
This species had a mean density of 38.1 cells/mL (Table 8) with a
mfl-g-imum of 201 cells/mL at Station 18 in April. Seasonally) mean
-------
maximum abundance occurred in spring (Fig. 25d). A second peak was
observed in October at Stations 34, 41 and 47.
Stichococcus sp.
3
With an average biomass of 2.0 mg/m (23 cells/mL), this
species contributed 0.50% of the total biomass. Seasonal distribution
was described by a late summer maximum that appeared to extend into
October. Occurrence was uneven; that is, it occurred only at Stations
6,18,34,41 and 47.
Chrysophyta
Dinobryon cylindricum Imhof, D. divergens Ehr., D. sociale var.
americanum (Brunnth.) Bachm.
Stoermer (1978) listed D. cylindricum ae a common element of the
Lake Michigan plankton community. In October of 1967, mean abundance
was 2.6 cells/mL (Parkos et al. 1969) for Dinobryon sp. Stoermer and
Kopczynska (1967a) noted that in 1962-63 Dinobryon was the most
important representative of the Chrysophyta in Lake Michigan. In
1962-63 J). divergens. D. cylindricum and D. sociale were the most
common species.
In the present study, these three species accounted for 3.66% of
the total biomass (Table 8). Along with Haptophyte sp., they were the
3
dominant chrysophytes. A mean biomass of 14.3 mg/m occurred for
the sampling period. Of the three species, D. sociale v. americanum
was the most prevalent. Maxima for all three species were in July
with a second maximum in August for D. divergens. Mean abundances
for all three species were higher (53.2 cells/mL) at Stations 64 and
77 than in the rest of the lake (21 cells/mL).
-------
Haptophyte sp.
3
With an average biomass and density of 2.3 mg/m and 185
cells/mL, respectively, this group constituted 0.59% of the total
biomass and 0.66% of the total cells. A maximum abundance of 785
cells/mL was observed on 4 July at Station 41. Differences in
seasonal abundance were evident with geography (Fig. 28b). Abundances
tended to be generally low in the south (Stations 6,11,18,23) till the
late summer and fall. In the central region (Stations 27,34,41),
peaks in abundance occurred in early July and later in August and
October. In the northern region (Stations 47,57,64,77), abundance was
high during the late spring and in October. Station 47 did not have
the spring pulse, but the fall pulse was observed.
Stylotheca aurea (Bachm.) Boloch.
This colorless flagellate was abundant in the spring (Fig. 27b).
3
Mean biomass was 2.1 mg/m representing 0.55% of the total
3
biomass. Abundance was especially high (39 mg/m ) at the far
northern stations (64 and 77) compared to the rest of the lake (0.5
mg/m3).
Cryptophyta
Chroomonas norstedtii Hansg.
Average density observed in 1983 was 28.8 cells/mL representing
0.1% of the total cells. Mean seasonal abundance was low in the
spring, reached a peak in July and leveled off at ~30 cells/mL for the
rest of the sampling period (Fig. 25f). This trend is somewhat
misleading because stations south of 34 did not experience this
-------
maximum in abundance,
far northern stations
lake (22 cells/mL).
Mean abundance was higher (59 cells/mL) at the
(Stations 64 and 77) than in the rest of the
Cryptomonas erosa Ehr. and C. erosa var. reflexa Marss.
Stoermer (1978) listed this species as present in only minor
quantities in Lake Michigan. Stoermer and Kopczynka (1967b) reported
cryptomonads as a numerically minor component of the total plankton.
Vollenweider et al. (1974) stated that Munawar observed Cryptomonas to
be commonly found.
Based on three samples in July 1973, Munawar and Munawar (1975)
reported that phytoflagellates contributed between 6% and 32% of the
biomass. Claflin (1975) also found small flagellates (particularly
Rhodomonas and Cryptomonas )to be abundant in 1970-71. Rockwell et
al. (1980) reported an occurrence of Cryptomonas spp. of 1,160
cells/mL in 1976.
In 1983 C. erosa and erosa v. reflexa had a combined mean
3
abundance and biomass of 7.9 cells/mL and 16.7 mg/m . On a
numerical basis, they represented only 0.02% of the total cells.
However, they did contribute 4.3% of the total biomass for the lake.
Seasonally, mean seasonal abundance for C. erosa reached a peak
in early May, decreased in July, increased to 7.6 cells/mL in August,
and remained at this level till late October when mean abundance
3
reached 13.7 cells/mL. Maximum biomass (74 mg/m ) occurred on 4
July at Station 23 and represented 13.4% of the total biomass for that
sampling station. No obvious geographic pattern was observed.
C. erosa v. reflexa displayed a different seasonal abundance
pattern with maxima in early August and in late October. Also,
-------
3
stations north of 41 had a mean biomass of 0.2 mg/m while the
3
rest had a mean biomass of 3.1 mg/m .
Cryptomonas marssonii Skuj a
Stoermer (1978) listed this species as being absent from Lake
Michigan. In 1983 this species had a mean abundance and biomass of
3
2.4 cells/mL and 2.2 mg/m (0.57% of the total biomass),
respectively (Table 8). A maximum abundance of 25 cells/mL (18.7
3
mg/m ; 14.9% of the biomass) was observed on 17 August at Station
41. Seasonally, abundance was higher in August through October than
in the spring and early summer (Fig. 26a).
Cryptomonas pyrenoidifera Geitl.
In 1983 a spring abundance peak was observed (Fig. 26a). Mean
3
abundance was 6.1 cells/mL. Average biomass was 2.8 mg/m
contributing 0.71% of the total biomass.
Rhodomonas minuta var. nannoplanktica Skuja
Stoermer (1978) reported this species as occasionally abundant in
Lake Michigan. Vollenweider et al. (1974) noted that Munawar and
Munawar observed R. minuta to contribute up to 5-10% of the biomass
for a sampling date in 1971. Some workers believe that R. minuta
var. nannoplanktica is not a distinct variety, but a smaller phase of
R minuta. Although Munawar and Munawar do not state this, it is
possible they lumped the variety nannoplanktica into R, minuta for
this reason or simply for convenience. Claflin (1975) also reported
small flagellates (particularly Rhodomonas and Cryptomonas) to be
abundant in 1970-71.
-------
In 1983 peaks in mean abundance were observed in early May and
October (Fig. 25f). No obvious geographical pattern was present.
3
Mean abundance and biomass were 269 cells/mL and 22.A mg/tn ,
respectively. This species contributed 5.7% of the total biomass to
the lake for the year.
Bacillariophyta
Asterionella formosa Hass.
Stoermer (1978) reported it as a common element of the Lake
Michigan plankton community. Stoermer and Yang (1970) indicated that
this species was relatively abundant throughout Lake Michigan and
reached its greatest relative abundance in late summer and early fall
samples. In 1962-63, A. formosa was abundant (ca. 20 cells/mL) in
August, declined in September and was abundant again in October (65
cells/mL) (Stoermer and Kopczynska 1967a). In 1967 its relative
abundance (numerical basis) was often 5-10% of the diatom assemblage.
Holland (1980) reported a maximum density of 226 cells/mL in 1971.
Rockwell et al. (1980) observed a mean abundance of 75 cells/mL for
southern Lake Michigan in 1976.
In 1983 mean abundance and biomass were 11.8 cells/mL and 3.5
3
mg/m , respectively. This species represented 0.91% of the total
biomass for the lake. Populations were low in the spring, reached a
mean mir-iwnmi abundance of 49.5 cells/mL in early July, decreased in
August and were increasing in mid-October (Fig. 26c), For the
sampling period, average densities were higher at Stations 27, 34 and
41 (25.5 cells/mL) and Station 77 (16.3 cells/mL) than in the rest of
the lake (5.3 cells/mL). Maximum abundance (206 cells/mL) occurred at
Station 32/34 on 4 July 1983. Maximum densities in 1971 (226
-------
52
cells/mL) and 1983 (206 cells/mL) were similar.
Cyclotella comensis Grun.
In 1962-63 C. michiganiana and C. comta were the major species
in the fall. C. kutzingiana. C. ocellata and C. stelligera were
also present but in smaller numbers. Holland (1980) did not report
this species. Stoermer and Tuchman (1979) reported this species as a
recent introduction to the nearshore southern Lake Michigan in 1977.
Abundance was low in June but increased substantially in August and
September. Average density was 86.7 cells/mL (1.9% of the population
with a maximum of 419 cells/mL) in 1977.
In 1983 mean abundance and biomass for the lake were 52.7
3
cells/mL and 2.0 mg/m , respectively (Table 8). A maximum of 834
cells/mL was observed at Station 77 in 3 August 1983. Density was low
from April to July, increased in August, and remained high to late
October when it increased to a mean abundance of 135 cells/mL for that
date (Fig. 26b). Geographically, mean station density was higher at
Stations 64 and 77 (x = 221 cells/mL) and Station 6 (X = 62 cells/mL)
at the far northern and southern ends of the lake as compared to the
rest of the lake (x = 9.5 cells/mL). This species represented 0.24%
of the total cells and on a numerical basis wa6 the dominant species
of Cyclotella.
Cyclotella comta (Ehr.) Kutz.
Previously published works indicate that this species is widely
distributed in oligotrophic and mesotrophic lakes (Stoermer and Yang
1970). Stoermer (1978) listed this species as occasionally abundant
in Lake Michigan. Schelske et al. (1971) and Holland and Beeton
-------
(1972) reported that C. stelligera was among the offshore dominants.
In July of 1969. an average density of 422 cells/mL was observed for
C_. stelligera (Schelske et al. 1971).
In 1983 abundance of C^. stelligera was less than 0.1% of the
total cells. On a biomass basis, C. comta was the dominant species
of Cyclotella (4.0% of the total biomass). Mean density and abundance
3
were 6.3 cells/mL and 15.6 mg/m , respectively. Maximum density
was 158 cells/mL. Abundance was low throughout the year reaching a
peak in October. Stations 64 and 77 experienced a substantially
higher mean station abundance (23.9 cells/mL) than in the rest of the
lake (2.3 cells/mL).
Cyclotella michiganiana Skv.
Stoermer (1978) listed this species as a common element of the
plankton community. Stoermer and Kopczynska (1967a) found it to be a
major dominant in collections from southern Lake Michigan in 1962 and
1963. Stoermer and Yang (1970) noted that most modern abundant
occurrences came from offshore stations in the extreme northern part
of the lake. In 1969 the mean abundance for July was 64 cells/mL
(Schelske et al. 1971). In 1965 Holland (1969) observed this species
to reach densities of **300 cells/mL and 100 cells/mL at the offshore
Michigan and Wisconsin stations. Highest abundance was in August.
In 1983 mean density and biomass were 12.1 cells/mL and 2.7
3
mg/m , respectively. This species represented 0.68% of the total
biomass (Table 8). Mean station abundance was low through August and
then steadily increased to 38 cells/mL in October (Fig. 26c). Even
peak density in 1983 (117 cells/mL) was lower than those abundances
observed by Holland (1969) in 1965.
-------
54
Cymatopleura solea (Breb. & Godey) W. Sm.
Stoermer and Kopczynska (1967a) reported this species as present
in small numbers in nearshore stations in 1962-63. Isolated
individuals were also occasionally noted in samples from the offshore
station. Low densities of 0.2 cell/mL were observed in Green Bay in
1977 (Stoermer and Stevenson 1979). Similarly low densities (0.16
cell/mL) were observed for southern Lake Michigan in 1977 (Stoermer
and Tuchman 1979).
In 1983 mean abundance was 0.3 cell/mL with a maximum of 3.7
cells/mL in April. Seasonally, peak abundance occurred in the spring
3
and late October. With a mean biomass of 6.0 mg/m , this species
represented 1.5% of the total biomass.
Entomoneia ornata (J.W. Ball.) Reim.
Stoermer and Tuchman (1979) reported a density of 0.05 cell/mL in
the nearshore of southern Lake Michigan in 1977. In 1983 a similar
density of 0.15 cell/mL was observed for all sampling stations. Mean
3
biomass (3.3 mg/m ) was relatively high (0.86% of the total
biomass).
Fragilaria crotonensis Kitton
During 1962-63 F. crotonensis was the major dominant in the
genus. In October of 1967, mean abundance was 1.3 cells/mL (Parkos et
al. 1969). Maximum abundance reported by Holland (1969) was —500
cells/mL. Schelske et al. (1971) reported mean abundances for July
and August/September of 1969 of 100 cells/mL and 15 cells/mL,
respectively. Stoermer and Yang (1970) stated that this species was
-------
the "most consistent major dominant" in the Lake Michigan flora
reaching its greatest relative abundance during the summer and early
fall. In 1976-77, Rockwell et al. (1980) observed a mean abundance of
325 cells/mL for the June-September period.
In 1983 mean abundance and biomass were 59.A cells/mL and A2.A
3
mg/m , respectively (Table 8). With major abundance peaks in July
and October (Fig. 26f), this species contributed 10.9% of the total
biomass. Mean station abundance was higher (129 cells/mL) at the
northern stations (64 and 77) as compared to the rest of the lake
(43.9 cells/mL).
Fragilaria vaucheriae (Kutz.) Peters.
Stoermer and Ladewski (1976) suspect that this species is
primarily benthic in habitat preference. A mean abundance of 0.A
cell/mL was observed in the nearshore of southern Lake Michigan in
1977.
In 1983 mean density and biomass were 10 cells/mL and A.6
mg/m , respectively (Table 8). Mean maximum station abundance (31
cells/mL) occurred in the spring (Fig. 26f). Mean station abundance
was greatest at the northern stations (57,6A,77) (2A.3 cells/mL) than
in the rest of the lake (x = 4.1 cells/mL).
Melosira islandica 0. Mull.
Stoermer (1978) listed this species as a common element of the
plankton assemblage. In 1962-63, M. islandica was by far the most
abundant member of the genus in the offshore waters of the lake
(Stoermer and Kopczynska 1967a). In 1965 maximum abundance in the
offshore waters was ~100 cells/mL during the spring (Holland 1969).
-------
56
In 1970 mean offshore density was 41 cells/mL in May (Holland and
Beeton 1972). In the nearshore of southern Lake Michigan in 1977,
this species constituted 0.04% of the population (1.5 cells/mL) with a
maximum of 27 cells/mL. Rockwell et al. (1980) reported a mean
Melosira sp. abundance of 186 cells/mL in 1976-77. Stoermer and Yang
(1970) reported it as a spring dominant.
In 1983 mean maximum station abundance occurred in the spring
(Fig. 27b). Mean abundance and biomass for the sampling period were
3
12.1 cells/mL and 10.9 mg/m , respectively. Maximum abundance was
137 cells/mL in May at Station 18. This species represented 2.8% of
the total biomass.
Melosira italica subsp. subarctica 0. Mull.
Stoermer (1978) listed this species as a common element of the
plankton of Lake Michigan. During 1962-63 Stoermer and Kopczynska
(1967a) reported M. islandica as the dominant species of this genus.
Holland and Beeton (1972) noted a mean abundance of 13.7 cells/mL at
offshore stations in January of 1971. Stoermer and Ladewski (1976)
reported this species as largely restricted to offshore stations. In
the nearshore during 1977, mean abundance of M. italica was 10
cells/mL with a maximum of 56 cells/mL.
In 1983 mean abundance was 37.6 cells/mL with a maximum abundance
of 357 cells/mL at Station 18 in early May (Table 8). Mean station
abundance peaked at 161 cells/mL in the spring (Fig. 27a). Abundance
in the southern half of Lake Michigan (51.9 cells/mL) was
substantially higher than in the northern half (23.9 cells/mL)
(Stations 34,41,47,64,77).
-------
57
Rhizosolenia eriensis H.S. Sm. and Rhizosolenia sp.
This species is widely distributed in large oligotrophic to
mesotrophic lakes of the world (Stoermer and Yang 1970). In May of
1962-63, relatively high (100 cells/mL) populations were observed in
southern Lake Michigan (Stoermer and Kopczynska 1967a). During May
and June of 1970, mean abundances for offshore stations were 63 and
611 cells/mL, respectively (Holland and Beeton 1972). Rockwell et al.
(1980) reported a mean density of 46.2 cells/mL for R. longiseta
during 1976-77.
In 1983 mean abundance was only 2.6 cells/mL, and it was
essentially absent from the lake except for high abundances in the
northern half of the lake in October (Fig. 28c). This species
contributed 1.6% of the biomass of the lake. In 1983 Rhizosolenia sp.
occurred only at Station 77. A small spring peak was observed with a
substantial bloom (133 cells/mL) in late October.
Stephanodiscus alpinus Hust.
The most common members of this genus in offshore collections in
1962-63 were ,S. transilvanicus and S. niagarae (Stoermer and
Kopczynska 1967), In 1970, Holland and Beeton(1972) reported an average of
3.7 cells/mL from the offshore region. Stoermer and Yang (1970)
reported that it was widely distributed in Lake Michigan, but abundant
occurrences were restricted to nearshore areas of the main lake. In
the nearshore zone of southern Lake Michigan during 1977, mean
abundance was 9.1 cell6/mL with a maximum abundance of 69 cells/ml.
In the present study, mean abundance and biomass were 2.9
3
cells/mL and 19.4 mg/m , respectively. Maximum abundance was 22
cells/mL. Mean station abundance was high in the spring (I = 7.4
-------
cells/mL) and in late October (3.2 cells/mL). This one species
accounted for only 0.01% of the total cells but 4.5% of the total
biomass for the sampling period.
Stephanodiecus niagarae Ehr.
Stoermer (1978) listed this species as present in minor
quantities. In 1962-63 Stoermer and Kopczynska (1967a) noted that the
most common members of this genus were SL transilvanicus and S^.
niagarae (abundance = 1.0 cell/ml). Stoermer and Yang (1970)
reported a high relative abundance in late spring and early fall.
Stoermer (1978) listed it as occasionally abundant. Stoermer and
Tuchman (1979) reported a mean abundance of 0.07 cell/ml in 1977.
In 1983 abundance was higher in the spring and late October (Fig.
26d). Mean abundance was only 0.79 cell/mL. but biomass averaged 9.9
3
mg/m . This species contributed 2.5% of the total biomass.
Stephanodiscus transilvanicus Pant.
Stoermer (1978) reported this species as a common element of the
plankton assemblage. In 1962-63 this species was a common member of
this genus with S. niagarae (abundance = 1.0 cell/mL). Stoermer and
Yang (1970) reported that the majority of abundant occurrences were
found in offshore samples. Stoermer and Tuchman (1979) did not
observe this species in the nearshore zone of southern Lake Michigan.
In 1983 mean abundance and biomass were 22.7 cells/mL and 0.3
3
mg/m , respectively (Table 8). Maximum abundance attained was 6
cells/mL in early October. Density was highest in the spring (Fig.
26d). This species contributed 1.6% of the total biomass.
-------
Tabellaria fenestrata Kutz.
Schelske et al. (1971) observed a July mean abundance of 72.5
cells/mL in 1969. According to Stoermer and Yang (1970).
fenestrata is nearly always present in phytoplankton collections from
Lake Michigan but usually makes up a minor part of the diatom
assemblage. Modern reports of abundant occurrences are essentially
restricted to offshore stations in the northeastern part of the lake.
In 1977 in the nearshore of southern Lake Michigan, a mean density of
1.4 cells/mL was observed (Stoermer and Tuchman 1979). Rockwell et
al. (1980) reported mean abundance of 77.1 cells/mL in 1976-77.
In 1983 mean abundance and biomass were 4.1 cells/mL and 7.2
3
mg/m , respectively (Table 8). Seasonally, mean station abundance
was high in spring (14.4 cells/mL) but near zero during the rest of
the sampling period (Fig. 26e). Abundance (13.1 cells/mL) in the
northern region of the lake was higher than in the stations south of
Station 57 (X = 0.78 cell/mL). Maximum abundance was 79 cells/mL at
Station 64 on 4 May 1983 (Fig 27d). This species represented 1.9% of
the total biomass.
Tabellaria flocculosa (Roth) Kutz.
Holland (1969) reported a maximum density of ~100 cells/mL in
offshore waters of Lake Michigan in 1965. During October, Parkos et
al. (1969) observed a mean density of 2 cells/mL. During 1970-72,
Holland (1980) reported an offshore mean density of 11.3 cells/mL. In
the nearshore of southern Lake Michigan in 1977, mean abundance was
122 cells/mL representing 2.3Z of the population (Stoermer and Tuchman
1979).
In 1983 the mean density of T. flocculosa was 16.8 cells/mL with
-------
a maximum of 202 cells/mL at Station 64 in May. Mean biomass was 48.9
3
mg/m representing 12.6% of the total biomass (Table 8). On a
biomass basin, this was the dominant diatom in the lake in 1983. Peak
abundance occurred in May (59.2 cells/mL) (Fig. 26e). Mean station
abundance was significantly higher (44.7 cells/mL) in the northern
region of the lake (Stations 57,64,77) as compared to the rest of the
lake (6.3 cells/mL).
-------
61
ZOOPLANKTON
Annual Abundance of Zooplankton Groups
Species lists (Tables A10-A12) and summary tables of abundance
(Tables A13-A18) are in Volume 2 - Data Report.
LAKE ERIE
The zooplankton assemblage was composed of 71 zooplankton taxa
representing 40 genera from the Rotifera, Cladocera, Calanoida,
Cyclopoida and Harpacticoida. The Rotifera possessed the largest
number of taxa (34) and relative abundance (69.2%), while the second
largest number of taxa (19) and abundance were observed for the
Cladocera (Table 9). In descending order of relative abundance were
the Cyclopoida, Calanoida and the Harpacticoida. The nauplius stage
of the Copepoda accounted for 15.8% of the total organisms observed.
The average density for the study period for all stations was 288,341
3
organisms/m (Table 10).
LAKE HURON
The zooplankton assemblage consisted of 61 zooplankton taxa
representing 33 genera from the Rotifera, Calanoida, Cyclopoida,
Cladocera and the Mysidacea. The Rotifera possessed the largest
number of taxa (31) and relative abundance (41.1%). In descending
order of relative abundance were the Calanoida, Cyclopoida, Cladocera
and tfysidacea (Table 9). The nauplius stage of the Copepoda accounted
for 23.1% of the total organisms observed. The average abundance for
3
the study period for all stations was 46,230 organisms/m (Table
19).
-------
62
LAKE MICHIGAN
The zooplankton assemblage consisted of 73 zooplankton taxa
representing 43 genera. The Rotifera possessed the largest number of
taxa (33) and the highest relative abundance (59.7%). In descending
order were the Calanoida, Cyclopoida, Cladocera, Harpacticoida and
Cyclopoida (Table 9). The nauplius stage of the Copepoda accounted
for 21.3% of the total organisms observed. The average abundance for
3
the study period for all stations was 69,353 organisms/m (Table
10).
Seasonal Abundance and Distribution of Major Zooplankton Groups
Seasonal analyses of zooplankton are of interest. Interpretation
of seasonal trends of the 1983 data set is limited because of the lack
of data from early May to early August.
LAKE ERIE
3
Seasonally, abundance (organisms/m ) appeared to be unimodal
increasing in late April to a summer maximum ("-400,000
3
organisms/m ) which continued till at least late August. By
October, abundance decreased to spring densities (Fig. 29). The shape
of the seasonal abundance pattern of zooplankton was determined by the
overwhelming dominance of rotifers during the spring, summer and fall.
The Cyclopoida increased in spring and began to decrease in abundance
from August to late October. The Calanoida and Cladocera increased in
abundance from April to August and then decreased into the fall (Fig.
30).
-------
LAKE HURON
Because zooplanktoti data (short hauls) are available only from
the late summer and early fall, seasonal analysis is not warranted.
LAKE MICHIGAN
3
Zooplankton abundance was low in April ("^.OOO organisms/m )
3
but appeared to progressively increase to ~150,000 organisms/m in
mid-October and then decreased by late October (Fig. 29). In the
spring, the Copepoda nauplii were the dominant group in the lake. By
August the Rotifera increased in abundance and remained the dominant
group within the lake to the last sampling date in October. The
pattern of distribution exhibited by the Rotifera was not observed in
the other zooplankton groups (Fig. 31). The Cyclopoida and Cladocera
appeared to increase in abundance from April to mid-October when a
slight decrease was evident by late October. The Calanoida appeared
to have a bimodal distribution with a summer maxima and late fall peak
(Fig. 31).
Geographical Abundance and Distribution of Major Zooplankton Groups
LAKE ERIE
Zooplankton abundance during the study period was greatest at the
western end of the lake, decreased easterly to Station 73, increased
3
to Station 79 and remained level at <*200,000 organisms/m in the
eastern end of the lake (Fig. 32). This geographical distributional
pattern was primarily determined by the abundance pattern of the
Rotifera. The Calanoida copepods generally increased in abundance
from west to east, while the Cyclopoida copepods had a higher
-------
abundance in the central basin. The Cladocera and the nauplius stage
of the Copepoda displayed no discernible geographical pattern.
LAKE HURON
The mean zooplankton abundance for the study period generally
decreased from north to south (Fig. 33) with the exception of Station
32. Much of this geographical distributional pattern was determined
by the abundance pattern of the Rotifera. Calanoida abundance was
lower in the north relative to the rest of the lake. Mean Cyclopoida
abundance was higher at the far northern and southern ends of the
lake. Cladocera abundance was relatively similar from station to
station on the north-south transect.
LAKE MICHIGAN
In comparison to Lakes Erie and Huron, a geographical
distributional pattern for zooplankton in Lake Michigan, if any
existed, was erratic. There was a suggestion of decreasing
zooplankton abundance from north to south (Fig. 34). Rotifera in
particular did decrease southward on the transect, while the Calanoida
had approximately twice the abundance in the southern half (Stations
34-6) than in the northern half (Stations 77-41) of the lake. The
3
Cladocera ranged from only 1,000 to 2,000/m except at Station 64
3
where a mean density of ^5,500/m was observed. No discernible
trends in Cyclopoida density were observed.
Size Frequency Analysis
Size frequency analyses were based on abundances obtained from
each lake from the epilimnetic tows (i.e. short hauls) and literature
-------
values of length for adult individuals.
LAKE ERIE
Eighty-four percent of the zooplankton observed were in the 0.1
to 0.3-mm size class. The rotifers and nauplius stage of the copepod
fell into this size class. Another peak (6.2%) in size frequency was
observed at the 0.6-mm size class. The copepodite stages of the
calanoid and cyclopoid copepods were the predominant groups in this
size category (Fig. 35).
LAKE HURON
Over 39% of the zooplankton observed were in the 0.6—mm size
class. The calanoid and cyclopoid copepods fell primarily into this
size class. Another large group of organisms (rotifers and nauplii)
(50%) were observed in the 0.1 to 0.3 size class (Fig. 35). This size
class distribution varied little with season or geography.
LAKE MICHIGAN
Seventy-nine percent of the zooplankton observed were in the 0.1
to 0.3 size class. Rotifers and the nauplius stage of the copepod
were the predominant organisms in this size range. Another peak in
size frequency was observed in the 0.6-min size class. The calanoid
and cyclopoid copepods were the predominant organisms in this size
class (Fig. 35).
Regional and Seasonal Trends in the Abundance of Common Taxa
LAKE ERIE
Crustacea were arbitrarily classified as common if they accounted
-------
66
for >0.1% of the total abundance for the study period. Rotifer
species were considered common if they accounted for >1.0% of the
total abundance.
Copepoda
Copepoda nauplii, Calanoida and Cyclopoida copepodite
Seasonal distribution and summary of average and maximum density
and relative abundance are presented in Table 11 and Fig. 36b and c.
Cyclopoida
Cyclops bicuspidatus thomasi
On a yearly basis, this is the most important species of
crustacean zooplankton in the Great Lakes (Balcer et al. 1984). Mean
3
abundance was 2,825 organisms/m representing 1.2% of the total
abundance (Table 11). This was the dominant Cyclopoida. Maximum
3
abundance (11,809/m ) occurred on 25 April at Station 37.
o
Abundance was generally higher (mean station abundance = 3,822/m )
3
in the central basin (Fig. 39b) than in the western (1,254/m ) or
3
eastern (1,636/m ) basins.
Mesocyclops edax
3
Mean abundance was 1,669 organisms/m representing 0.7% of
the total abundance (Table 11). Mean cruise abundances peaked in
3
early August at 3*960 organisms/m which agreed with most workers
3
(Balcer et al. 1984). Maximum abundance was 14,584 organisms/m
at Station 79 on 6 August. Abundance was greater in the central and
eastern basins (Fig. 40a).
-------
Iropocyclops praeinus mexicaaus 67
Average density in the short hauls (epilimnetic tows) was 748
3
organisms/m . Density was considerably higher in the long hauls
3 3
(1,742/m ). Maximum abundance was 3,300 organisms/m in
October at Station 9. Abundance increased dramatically from west to
east (Fig. 39c). Mean station abundances in the western, central and
3
eastern basins were 112, 617 and 1,104 organisms/m , respectively.
Peak abundance generally occurred in late summer and early fall.
Calanoida
Diaptomus oregonensis
Balcer et al. (1984) reported this species as being most abundant
in the summer and fall. This agreed well with the 1983 observation of
3
peak mean cruise abundances of 3,558 and 5,505 organisms/m on 6
and 22 August (Fig. 39a). Abundance was greatest in the central basin
3
(mean station abundance = 2,385/m ) as compared to the western
3 3
(116/m ) and the eastern basins (2,011/m ). Mean abundance
3
was 2,034 organisms/m making it the dominant Calanoida.
Diaptomus siciloides
In Lake Erie this species is one of the most abundant calanoid
copepods during the summer months, ranking second to D. oregonensis
(Davis 1961). Average abundance in July of 1967 was —1,710
3 3
organisms/m (Davis 1968) with peaks of 15,800/m (Rolan et
al. 1973) in 1971 near Cleveland.
3
In 1983 mean density was 600 organisms/m (0.2% of the total
3
organisms) with a maximum of 13.334 organisms/m at Station 15 on
6 August. No obvious geographical pattern was observed, but there is
a suggestion that abundance in the western and eastern basins was
-------
68
higher than in the central basin. Mean maximum seasonal abundance
3
(1,865/m ) occurred in early August (Fig. 36a).
Cladocera
Bosmina longirostris
Abundance generally peaks in late summer or early fall (Balcer et
al. 1984) which appears to agree with the 1983 observations. Mean
3
seasonal abundance ranged from 1,303 to 1,524 organisms/m from
April to 19 October. By 24 October, mean seasonal abundance increased
3
to 2,187 organisms/m (Fig.38f). For the sampling period, mean
3
station abundance was higher in the western basin (1,939/m ) than
3 3
in the central (1,139/m ) and eastern basins (1,047/m ). This
pattern was especially noticeable during the October maximum when the
3
western basin experienced considerably higher densities (6,182/m )
3
than in the rest of the lake (689/m ). Mean abundance for the
3
sampling period was 1,628 organisms/m representing 0.7% of the
total organisms.
Eubosmina coregoni
Balcer et al. (1984) reported that abundance can reach 47,000
3 3
organisms/m . In 1983 mean abundance was 4,505 organisms/m
3
with a maximum of 64,384/m at Station 57 in late October. Mean
3
station abundance of the western basin (6,213/m ) was greater than
3
in at the rest of the lake (2,738/m ). Seasonally, two abundance
peaks were evident in late August and late October (Fig. 36d). This
species was the dominant cladoceran in the lake contributing 1.7% of
the abundance.
-------
69
Chydorus sphaericus
This species is occasionally abundant in Lake Erie
3
(3,000-30,000/m ) (Balcer et al. 1984). Mean abundance was low in
3
1983 (476/m ) (Table 11), but mean seasonal abundance was high in
3
October (1,309/m ) (Fig. 36d). Maximum abundance was
3
14,902/m at Station 73 on 19 October.
Daphnia retrocurva
This species is one of the most abundant cladocerans in the Great
3
Lakes. Densities of 4,000-10,000/m have been reported for Lake
Erie with peaks in abundance as early as June in Lake Erie (Balcer et
al. 1984). Mean seasonal abundance was low in April and May, was high
3
(7,150/m ) from July to August and decreased in October (Fig.
3
36e). A maximum abundance of 69,542 organisms/m was observed at
Station 55 in the western basin on 19 October. Mean abundance was
3
4,183 organisms/m representing 1.4% of the total organisms.
Daphnia galeata mendotae
Historically, this species has been quite abundant (average =
900-5,000/m^) with peaks of 270,000/m^ (Balcer et al. 1984).
3
In 1983 mean abundance was 4,055 organisms/m representing 1.5% of
the total biomass (Table 11). They were not present in April and May
and first appeared in our samples in early August (mean abundance for
3
6 August = 11,453/m ) and decreased in abundance till October
3
(Fig. 38e). The western basin had a lower abundance (298/n ) than
3
the rest of the lake (4,450/m ). Maximum abundance was 60,151
3
organisms/m at Station 18 on 6 August.
-------
70
Diaphanosoma leuchtenbergianum
Iti Lake Erie, Diaphanosoma is most abundant in the western basin
in July and in the eastern and central basins during the fall (Balcer
et al. 1984). In the 1983 sampling, an abundance peak was observed on
3
22 August (x = 4,323/m ) (Fig. 36e). No obvious geographical
pattern was observed. Mean abundance for the sampling period was 966
3
organisms/m representing 0.4% of the total organisms (Table 11).
Rotifera
Polyarthra vulgaris
3
Mean abundance was 49,739 organisms/m representing 18.4% of
the total organisms (Table 11). Maximum abundance attained was
3
334,317 organisms/m at Station 57 on 22 August. This was the
dominant zooplankter in 1983. Mean seasonal abundance was highest in
3
late August (87,804/m ) (Fig. 38a). Density decreased from the
3 3
western (60,567/m ) to the central (37,222/m ) to the eastern
3
basin (26,561/m ).
Polyarthra dolichoptera
3
With a mean abundance of 8,329/m , this species contributed
2.7% of the total abundance (Table 11). Mean seasonal abundance
3
peaked at 33,900 organisms/m in early May (Fig. 38a). No
geographical patterns were observed.
Polyarthra major
3
Mean peak seasonal abundance Ovl0,000/m ) occurred in the
late summer and fall (Fig. 38b). Mean abundance for the sampling
3 3
period was 6,395 organisms/m with a maximum of 24,657/m at
-------
71
Station 42 in late October. Abundance was slightly higher in the long
hauls (Table 11).
Keratella cochlearis
3
With a mean abundance of 19,647 organisms/m , this species
contributed 7.3% of the total organisms. With a maximum of 110,636
3
organisms/m in May at Station 60, this was the third most
dominant rotifer and species in the lake. Mean seasonal abundance
3
reached a peak (42,490/m ) in August (Fig. 37c). Abundance in the
3
western basin (24,709/m ) was higher than in the central and
3
eastern basins (12,837/m ).
Keratella hiemalis
3
With a seasonal mean abundance peak of 47,244 organisms/m in
May, this species appeared to be restricted in distribution to the
central basin (Fig. 42b). Mean abundance for the sampling period was
3 3
10,701 organisms/m with a maximum of 127,000/m at Station 42
in May (Table 11).
Keratella crassa
3
This species had a mean abundance of 5,384 organisms/m
during the sampling period representing 1.8% of the total organisms
3
(Table 11). Maximum mean seasonal abundance (19,165/m ) occurred
3
in late August (Fig. 37d). A maximum of 97,000 individuals/m was
observed on 22 August at Station 57 (Table 11).
Keratella earlinae
Although this species was not a common species, its distribution
-------
72
pattern was of interest. This species generally had a restricted
geographical distribution to the western basin with only a few minor
occurrences in the central basin (Fig. 41a).
Synchaeta sp.
Mean maximum seasonal abundance occurred in early August in the
western basin. Abundance was low in the rest of the lake (Fig. Alb).
3
Mean abundance for the sampling period was 29,442 organisms/m
3
with a maximum of 370,000/m in early August at Station 60. This
species was the second most dominant zooplankton and rotifer in the
lake contributing 9.5% of the abundance.
Brachionus sp. and B. caudatus
Brachionus sp. contributed 3.0% of the total abundance and had a
3
mean abundance of 9,307 individuals/m (Table 11). This species
3
had the highest abundance (540,369/m ) observed of any species in
Lake Erie. Distribution was limited to the extreme western end of the
western basin with mar-jimim abundance in early August (Fig. 40b).
Although B. caudatus was not a common species, a similar distribution
limited to western basin was observed (Fig. 42c).
Ascomorpha ecaudis and Ascomorpha sp.
3
Maximum mean seasonal biomass occurred in August (20,773/m )
(Fig. 38d). Geographically, it was observed in the western and
3
central basin (mean station abundance = 7,252/m ) but not in the
3
eastern basin. Mean abundance was 6,446 individuals/m . Seasonal
distribution of a minor species Ascomorpha sp. is given in Figure 38d.
-------
73
Notholca laurentiae
Mean seasonal abundance peaked in early May at 20.632
3
organisme/m . Geographically, abundance was low in the eastern
3
basin (mean station abundance = 1207/m ) as compared to the
3 3
western (9050/m ) and central basins (6383/m ). Mean
3
abundance was 6,964/m .
Notholca foliacea
Abundance varied geographically with mean station abundance low
3
in the eastern basin (184 individuals/m ) as compared to the
3 3
western (10,357/m ) and central basins (3,399/m ). Maximum
3
mean seasonal abundance occurred in May (18,583/m ) (Fig. 37f)
with abundance near zero during the rest of the sampling period. Mean
3
abundance was 5,402 organisms/m .
Colletheca sp.
Abundance was low in April and May, reached a peak (mean August
3
abundance = 18,400/m ) in mid-August and decreased by late
3
October. Mean station abundance was highest (5,917/m ) in the
3
central basin (western basin - 2,158/m ; eastern basin =
3
3,872/m ). Mean abundance for the sampling period was 5,402
organisms/m^.
Kellicottia longispina
Two maxima in abundance were observed (Fig. 37b). The central
basin had the highest abundance (mean station abundance =
3 3
4,457/m ) followed by the western (2,437/m ) and eastern
basins (902/m3).
-------
74
Less Common Species
Graphical representations of the seasonal abundance of the
following less common species are given: Asplanchna priodonta (Fig.
36f), Conochilus unicornis (Fig. 37a), Ploesoma sp. (Fig. 37b),
Keratella quadrata (Fig. 37c), Notholca squama!a (Fig. 37e),
Polyarthra ma.jor (Fig. 38b) and Gastropus stylifer (Fig. 38c).
The following less common species of distribution were distinctly
limited to the western basin: Filinia longiseta (Fig. 40c),
Keratella earlinae (Fig. Ala), Trichocerca cylindrica (Fig. 41c) and
Trichocerca multicrinis (Fig. 42a).
-------
LAKE HURON
Crustacea were arbitrarily classified as common if they accounted
for >0.1% of the total abundance for the study period. Rotifer
species were considered common if they accounted for >1.0% of the
total abundance.
Copepoda
Copepoda nauplii, Calanoida and Cyclopoida copepodite
Seasonal distribution and summary of average and maximum density
and relative abundance are presented in Table 12 and Figures 43c and
d.
Cyclops biscuspidatus thomasi
This species is one of the most common and widely distributed
copepods in North America. Balcer et al. (1984) reported this species
as abundant in Lake Huron. In 1983 this was the dominant cyclopoid in
Lake Huron accounting for 1.1% of the total abundance (Table 12).
3
Abundance (533/m ) was slightly higher at the extreme northern end
of the lake (Stations 51 and 64) than in the rest of the lake
3 3
(230/m ). Mean maximum seasonal abundance (925/m ) occurred
in early August (Fig. 43d).
Tropocyclops prasinus mexicanus
Balcer et al. (1984) reported this species as being present in
Lake Huron since 1967. Abundance historically has peaked between
August and November (Balcer et al. 1984). In 1983 a maximum abundance
3
(mean October density = 267/m ) was observed in mid-Octobr (Fig.
-------
76
43e). No obvious geographical pattern was noted. Mean abundance for
3
the sampling period was 109 organisms/m with a maximum of
3
577/m at Station 15 in October (Table 12).
Mesocyclops edax
Balcer et al. (1984) reported this species as being most common
in Lakes Erie and Michigan. In 1983 this was the third most common
3
cyclopoid with a mean density of 115 organisms/m and a max-imum
3
density of 930 organisms/m at Station 12 in mid-August. Mean
3
maximum seasonal abundance occurred in August (267/m ). Abundance
3
was slightly higher south of Saginaw Bay (99/m ) compared to the
3
area north of it (41/m ).
Calanoida
Diaptomus minutus
This species has been found in all the Great Lakes but is most
abundant in Lakes Huron (Patalas 1972) and Michigan (Gannon 1972). In
the present study, it was the dominant calanoid with a mean abundance
3
of 465 organisms/m representing 0.8% of the total abundance.
3
Mean maximum seasonal abundance (911/m ) occurred in early August
(Fig. 46a). Abundance was low in the north and peaked at mid-lake
(Stations 37,32,27) and in the southern region of the lake (Stations
3
12,9,6) (Fig. 46a). Maximum density of 2,063 organisms/m
occurred at Station 6 on 4 August.
Diaptomas sicilis
Balcer et al. (1984) reported this species as occurring in low
numbers in Lake Huron. D. sicilis is generally found during all
-------
77
seasons, but the adults are generally most abundant between January
and June. In 1983 mean minimum seasonal abundance occurred in August
3 3
with maxima at the first (208/m ) and last (295/m ) sampling
dates (Fig. 43b) suggesting a winter maximum. No obvious geographical
pattern was observed.
Diaptomus oregonenais
This species is most abundant in the Great Lakes in the summer
and fall (Balcer et al. 1984). In 1983 mean maximum seasonal
3
abundance (177/m ) occurred in August. Mean abundance for the
3
sampling period was 140 organisms/m with a maximum of 413
3
individuals/m at Station 12 on 19 August.
Cladocera
Daphnia galaeta mendotae
This species was the dominant cladoceran in the lake with an
3
average density of 1,029 organisms/m representing 1.4% of the
total abundance (Table 12). Maximum abundance was 4.076
3
individuals/m at Station 9 in early August. Two maxima were
3
observed in August (mean August abundance = 1,328/m ) and October
(1,117/m3).
Daphnia pulicaria
Balcer et al. (1984) noted that pulicaria has not been
observed in the Great Lakes. Evans (1985) recently reported that D.
pulicaria was a new species dominating Lake Michigan. In 1983 in Lake
Huron, Daphnia pulicaria was observed to be the third most important
3
cladoceran (Table 12). Mean abundance was 363 organisms/m with a
-------
78
3
maximum of 2,791 organisms/m at Station 12 on 19 August. Mean
3
maximum seasonal abundance occurred in mid—August (730/m ) (Fig.
44a). Mean station abundance increased from north to south with a
mean density for stations south of Saginaw Bay of 431
organisms/m^.
Daphnia retrocurva
I). retrocurva is most common in the nearshore zone of the
Great Lakes appearing in the open waters only during peak abundance
(Balcer et al. 1984). In 1974-75, McNaught et al. (1980) reported it
as an uncommon species in Lake Huron. In 1983 mean abundance was
3
74/m . Abundance was generally low for the lake except for the
3
far north where a maximum of 2,148 organisms/m was observed at
Station 61 in mid-August.
Daphnia catawba
Balcer et al. (1984) did not list this species as a common or
less common species of the Great Lakes. In 1983 it did not appear in
the short hauls (Table 12). However, a maximum abundance of 1,610
3
organisms/m was observed from Station 12 in August from the long
3
hauls. Mean maximum seasonal abundance was 442 organisms/m in
mid-August.
Holopedium gibberum
Abundance along the western side of Lake Huron ranged from 7-17
3
individuals/m (Basch et al. 1980). In 1983 mean abundance of 58
3 3
organisms/m with a maximum of 408/m occurred at Station 61
in August. Mean seasonal abundance reached a maximum of 125
-------
79
3
organisms/m in early August. Mean station abundance was higher
3 3
north of Station 37 (63/m ) than south of it (8.6/m ).
Rotifera
Conochilus unicornis
This colonial rotifer was the dominant zooplankter in 1983 in
Lake Huron (11.2% of the total abundance) (Table 12). Mean seasonal
3
abundance peaked in early August (10,927/m ) with abundance being
higher north of Saginaw Bay (Fig. 47a).
Kellicottia longispina
3
With an average density of 2,088 individuals/m , this species
contributed 8.6% of the total abundance. Maximum density was
3
7,106/m in the short hauls. However, a maximum density of 21,721
3
organisms/m was observed in the long hauls suggesting that this
species is found in higher densities in the metalimnion and/or
hypolimnion (Table 12). Mean seasonal abundance peaked in early
August (Fig. 47b) with abundance being slightly higher north of
3 3
Saginaw Bay (north: 1,282/m ; south: 838/m ).
Keratella cochlearis
3
Mean abundance was 2,040 organisms/m representing 7.2% of
the total abundance (Table 12). Maximum abundance in the short haul
3
(epilimnetic tow) was 5,457/m , which is considerably less than
3
the maximum abundance (18,633/m ) observed from the long haul.
3
Mean seasonal abundance peaked at 3,521 organisms/m in early
August (Fig. 44d).
-------
80
Polyarthra vulgaris
Mean maximum seasonal abundance occurred in mid-August
3
(4,691/m ) (Fig. 45b). This species accounted for 5.3% of the
3
total organisms (2,955/m ) (Table 12).
Gastropus stylifer, Synchaeta sp., Colletheca sp.
Average abundance and maximum abundance for these common species
are presented in Table 12. Mean seasonal abundance is presented in
Figures 44c and 45c.
Less Common Species
The seasonal distributional patterns of less common species are
presented in the following figures: Asplanchna priodonta (Fig. 44c);
Keratella crassa, K. earlinae and K. quadrata (Fig. 44e); Notholca
laurentiae. N. squamula (Fig. 44f); and Polyarthra major, and P.
dolichoptera (Fig. 45a).
-------
81
LAKE MICHIGAN
Crustacea were arbitrarily classified
for >0.1% of the total abundance for
species were considered common if they
total abundance.
Copepoda
Copepoda nauplii, Calanoida and Cyclopoida copepodite
Seasonal distribution and summary of average and mavimnm density
and relative abundance are presented in Table 13 and Figure 48c and d.
Cyclopoida
Diaptomus ashlandi
JD. ashlandi has been reported as the dominant calanoid copepod
in the open waters of Lake Michigan usually exceeding 1,000
3
individuals/m (Balcer et al. 1984). In 1983 this species
3 3
averaged 699 organisms/m with a maximum of 6,536/m at
Station 64 on 3 August. Mean maximum seasonal abundance occurred in
3
early August (2,243/m ) (Fig. 48a). Contributing 1.1% of the
total abundance, this species was the dominant calanoid copepod in
1983.
Diaptomus sicilis
In Lake Michigan, abundance declined between 1954 and 1968 (Wells
3
1970). It averaged less than 100/m in the early 70's in the open
lake (Gannon 1972). In 1983 average abundance for the lake was 386
3 3
organisms/m with a maximum of 4,200 individuals/m (Table 12)
as common if they accounted
the study period. Rotifer
accounted for >1.0% of the
-------
82
at Station 32 on 26 October. Mean maximum seasonal abundance
3
(1,282/m ) occurred in late October. Abundance was definitely
higher in the southern half of the lake (south of Staton 32) in
3
October (mean station abundance = 2,327/m ) (Fig. 51a).
Diaptomus minutus
Gannon (1972) ranked this species as the second most important
calanoid in the early 1970's. Peaks in abundance may exceed a few
thousand organisms per cubic meter (Balcer et al. 1984). In 1983
3
average abundance was 167 organisms/m with a maximum of
3
812/m at Station 56 in late April. No obvious geographical or
seasonal pattern was observed (Fig. 48b).
Diaptomus oregonensis
I). oregonensis was not collected from Lake Michigan in 1927
(Eddy 1927, Beeton 1965) but by the 70's had become the most common
diaptomid in Green Bay (Gannon 1972) and may often outnumber Diaptomus
sicilis in the open waters of the lake (Wells 1960). Peaks of 2,580
3
individuals/m have been observed in the summer in shallow areas
of Lake Michigan (Howmiller and Beeton 1971).
In 1983 this species was the fourth most important diaptomid with
3
a mean abundance of 115 organisms/m . Mean maximum seasonal
3
abundance was 167 organisms/m in early August (Fig. 48b).
3
Maximum abundance (1,018/m ) was observed at Station 32 in late
October.
Limnocalanus tnacrurus
Gannon (1972) reported this species as having a low abundance in
-------
83
southern Lake Michigan. In 1983 a mean abundance of 138
3 3
organisms/m occurred with a maximum of 1,725 organisms/m in
April at Station 22. Mean seasonal abundance was higher in the spring
3 3
(257/m ) than during the rest of the sampling period (17/m ).
3
Mean station abundance was low (26/m ) at the far northern
stations (Stations 56,64,77) as compared to areas south of Station 56
(155/m3).
Cyclopoida
Cyclops bicuspidatus thomasi
On a yearly basis, this species is the most important species of
the crustacean zooplankton in the Great Lakes. In the present study,
it was the dominant cyclopoid contributing 1.6% of the total abundance
3 3
(x = 1,140/m ). Maximum abundance (5,216/m ) was observed on
3 August at Station 66. No obvious geographical pattern was observed.
Two maxima in mean seasonal abundance occurred in early August
(1,895/m^) and October (1,459/m^) (Fig. 48e).
Tropocyclops prasinus mexicanus
3
In 1983 mean density was 238 organisms/m with a maximum of
3
3,600/m on 12 October at Station 10 (Table 12). Mean maximtim
3
seasonal abundance peaked in October at 669 organisms/m .
Cladocera
Bosmina longirostris
3
In 1983 mean abundance was 923 organisms/m contributing 1.4%
of the total abundance. This was the dominant cladoceran in the lake.
3
Maximum abundance was 17,000/m (Table 12) which is considerably
-------
84
less than the 29,000-230,000 reported in Green Bay and the nearshore
of Lake Michigan by Gannon (1974) and Stewart (1974). Mean seasonal
3
maximum abundance occurred in early October (3,422/m ) with
abundance higher at the northern stations (Fig. 51b).
Daphnia galaeta mendotae
3
Densities of 100-6,000/m have been observed in Green Bay and
the nearshore of Lake Michigan in the early 70's. In 1983 two mean
3
seasonal abundance maxima were observed in July (741/m ) and
3
October (1,026/m ) (Fig. 48f). Mean abundance observed was 445
3
organisms/m representing 0.6% of the total abundance (Table 12).
No obvious geographical patterns were apparent.
Daphnia pulicaria
Balcer et al. (1974) noted that D. pulicaria has not been
observed in the Great Lakes. Evans (1985) recently reported that D.
pulicaria was a new species dominating Lake Michigan. A maximum
3
abundance of 954 organisms/m was observed in July.
3
In 1983 mean abundance for the sampling period was 445/m
3
with a maximum of 6,100/m at Station 26 on 3 August. Mean
3
seasonal abundance peaked in early August at 1,741 organisms/m
(Fig. 48f). When both the short and long hauls are considered, this
was the dominant species of Daphnia in the lake.
Daphnia retrocurva
Abundances were highest in the summer with maximum densities of
3
2,000-24,000 organisms/m during the early 70's (Balcer et al.
3
1984). In 1983 mean abundance was 115/m with a maximum of
-------
85
3
3,200/m at Station 5 on 12 October. Mean seasonal abundance
3
peaked in early October (430/m ) with density highest in southern
Lake Michigan (Fig. 51c).
Eubosmina coregoni
In April and May, abundance was low. By August, density
3
increased to 167 organisms/m and stayed at that approximate
abundance to October (Table 12). Abundance was higher at Stations 64
3 3
and 77 (356/m ) than in the rest of the lake (21/m ).
Holopedium gibberum
Abundance peaks generally occur betwen June and October (Balcer
3
et al. 1984). Mean abundance in 1983 was 86/m . Mean maximum
3
seasonal abundance (679/m ) occurred in early August (Fig. 49a).
3
Abundance at Stations 64 and 77 (395/m ) was much higher than in
3
the rest of the lake (3.4/m ).
Rotifera
Polyarthra vulgaris
This species was the dominant zooplankton in Lake Michigan
contributing 20.8% of the total abundance (x abundance =
3 3
16,996/m ). Maximum abundance was 109,000/m (Station 46; 17
August). Abundance was low in April and May but by mid-August a mean
3
abundance of 42,598/m was observed and maintained into early
October (Fig. 50c).
Svnchaeta sp.
3
With a mean seasonal abundance peak (24,000/m ) in mid-August
-------
86
(Fig. 49c), this species had a mean abundance for the lake of 8,593
3
organisms/m (Table 12).
Keratella cochlearis
3
Mean abundance was 3,463 organisms/m in 1983 representing
7.2% of the total abundance (Fig. 50a). Peak abundance occurred in
3
late October (mean October abundance = 8,157/m ). Abundance
_ 3
decreased from north to south (Stations 64 and 77; x = 11,470/m ),
3
(Stations 40,46,50; x = 2,574/m ), (Stations 5,10,17,22,26,32; x =
959/m3).
Polyarthra maj or
Mean maximum seasonal abundance occurred in early October
3 3
(4,856/m ) (Fig. 50b). Mean abundance was 1,928 organisms/m
3
with a maximum of 23,000/m at Station 40 on 12 October. This
species represented 3.1% of the total abundance.
Kellicottia longispina
Mean abundance was considerably higher in the long tow
3 3
(4,688/m ) relative to the short tow (981/m ) suggesting that
this species was more prevalent in the metalimnion or hypolimnion.
Mean maximum seasonal abundance occurred in early August (x =
2.446/m3).
Conochilus unicornis
3
Mean seasonal abundance reached a peak in August of 4,457/m
3
(Fig. 49d). Mean abundance was 1,772/m with a maximum of
21,000/m on 17 August at Station 77 (Table 12). Mean station
-------
87
3
abundance was greater at Stations 64 and 77 (4,285/m ) than in the
3
rest of the lake (932/m ).
Other Common Species
Seasonal distribution patterns and mean and maximum abundances of
the following species can be found in Table 12 and the following
figures: Polyarthra dolichoptera (Fig. 50b), Keratella crassa (Fig.
50a), Gastropus stylifer (Fig. 49e), Colletheca sp. (Fig. 49d),
Keratella earlinae (Fig. 49f) and Notholca squamula (Fig. 52b).
Less Common Species
Seasonal distribution of the following less common species can be
found in the following figures: Asplanchna priodonta (Fig. 49b),
Keratella quadrata (Fig. 49f), Ascomorpha sp. and Ploesoma sp. (Fig.
50d), and Notholca laurentiae and N. foliacea (Fig. 52a and c).
Differences Between the Long and Short Zooplahkton Hauls
LAKE ERIE
Polyarthra major, Mesocyclops edax and Cyclops bicuspidstus
thomesi all had mean abundances that were higher in the long hauls
(Table 14). Abundances of these species were greater in the
metalimnion or hypoliranion.
LAKE HURON
Significantly higher abundances were observed in the long hauls
of the following: Copepoda nauplii, Keratella cochlearis. Synchaeta
Bp., Keratella earlinae, Keratella quadrata and Notholca
laurentiae (Table 15). Only those organisms observed in either the
-------
long or the short hauls are listed in Table 16. Of particular
significance are Daphnia catawba and Notholca squamula which were
both abundant. D^. catawba is not a common species to the Great
Lakes.
LAKE MICHIGAN
Abundance of Keratella quadrata was higher in the long hauls
compared to the short hauls (Table 17). Organisms observed only in
the short or long hauls are listed in Table 18. Most of these
occurrences represent a low abundance and define the rarity of these
species.
-------
DISCUSSION
PHYTOPLANKTON
LAKE ERIE
Changes in Species Composition
Division Trends
One hundred twenty-five to 150 species were identified in Lake
Erie during 1970 (Munawar and Munawar 1976), which was considerably
lower than the 37 2 species observed in 1983, Also contrary to the
1970 study was the fact that the Bacillariophyta possessed the largest
number of species in 1983 rather than the Chlorophyta, which was the
second largest group. The diatoms, representing 59.9% of the
phytoplankton biomass, were also the dominant group in the lake, while
the green algae were the second most important group (14.9% of the
biomass).
Species Trends - The Entire Lake
Davis (1969b) has reviewed the extensive earlier work on Lake
Erie, while Munawar and Munawar (1982), Gladish and Munawar (1980) and
Nicholls (1981) discuss the more recent material. Verduin (1964) h&fi
concluded that before 1950 the phytoplankton of western Lake Erie had
been dominated by Asteriocella formosa, Tabellaria fenestrata and
Melosira ambigua, whereas in 1960-1961 the dominant forms had been
Fragilaria capucina, Coscinodiscus radiatus (probably Actinocyclus
normanii f. subsalsa) and Melosira binderana (= Stephanodiscus
binderanus).
As with Munawar and Munawar (1976), this study confirms Verduin*a
-------
observations that those species dominant before 1950 (A. formosa. T.
fenestrate and M. ambigua) continued to be less important in the 1983
collections. Actinocyclus normanii f. subsalsa (= Coscinodiscus
rothii) and Stephanodiscus binderanus were dominant in 1961-1962
(Verduin 1964) and in 1970 (Munawar and Munawar 1976). Fragilaria
capucina was a dominant in 1961 but not in 1970. By 1983 Actinocyclus
normanii f. subsalsa was only the fifth most prevalent diatom, but on
a numerical basis Fragilaria capucina was the second most prevalent
diatom in the western basin and in the entire lake (Table 6).
Dominant species in 1983 were Stephanodiscus niagarae.
Fragilaria crotonensis, Fragilaria capucina, Coelastrum
microporum, Cosmarium sp., Cryptomonas erosa, Rhodomonas var.
nannoplanktica, Anacystis marina, Oscillatoria subbrevis.
Oscillatoria tenuis and Ceratium hirundinella (Table 6). Although
occurrence of common and dominant species in 1970 and 1980 were
similar, dramatic decreases in abundance of these species were evident
(Table 20). This pattern was evident in all three basins. Nicholls
et al. (1977b) also observed decreases in abundances of diatoms,
especially during the 1967-1975 period.
Species Trend - Western Basin
Hohn (1969) and Munawar and Munawar (1976), working with data
from the western basin of Lake Erie, described long-term changes in
the diatoms from 1938 to 1970. (1) Both workers agreed that
Cyclotella stelligera and Rhizosolenia eriensis had decreased in
abundance during the period. Both species were present in 1983 but
were still relatively unimportant (Table 6). (2) In 1970
Stephanodiscus binderanus and Stephanodiscus spp. (S_. niagarae. S.
-------
tenuis and £. hantschii) were frequent but not alpinue which Hohn
(1969) observed to be dominant. In 1983, S. binderanus. the dominant
S. niagarae and £>. alpinus were all abundant (Table 6) in all three
basins.
Picoplankton
The autotrophic nature of picoplankton has been brought to the
attention of phycologists in recent years (Johnson and Sieburth 1979,
1982; Li et al. 1983). In the Great Lakes, Sicko-Goad and Stoermer
(1984) presented the first evidence of picoplankton, while Caron et
al. (1985) documented the occurrence of photosynthetic chroococcoid
cyanobacteria (0.7 - 1.3 jim in diameter) in Lake Ontario. The
overwhelming abundance of picoplankton (probably Anacystis marina and
Coccochloris peniocystis, Table 6) in the 1983 samples is of
interest. Density in Lake Erie during 1983 (5 = 33,171 cells/mL;
3
ipn-r-itninn of ~141 x 10 cells/mL) was comparable to the picoplankton
3
density in Lake Ontario which ranged from x 10 to 6.5 x
103
cells/mL. Munawar and Munawar (1976) and Gladish and Munawar
(1980), using comparable enumeration and preservation techniques in
their studies, did not report these species. It is reasonable to
assume that previous Great Lakes' workers ignored this small-sized
fraction when enumerating phytoplankton, believing them to be
bacterial in nature.
Baft-West Species Distribution
Munawar and Munawar (1976) and Davis (1969b) have documented the
existence of differences in species abundances from the central,
western and eastern basins. In 1983 at least 12 species had higher
-------
abundances or abundances restricted to the western basin: Anacystis
marina, Oscillatoria tenuis and Oscillatoria limnetica (Fig.
I6a-c); Oscillatoria subbrevis (Fig. 17a and b); Cryptomonas erosa.
Fragilaria crotonensis and Tabellaria flocculosa (Fig. 18a-c) and
Melosira granulata (Fig. 19), Fragilaria capucina and Stephanodiscus
bjnderanus. Six species Coelospharium naegelianum, Pediastrum
simplex. Rhodomonas minuta var. nannoplanktica, Peridinium
aciculifer^m, Stephanodiscus niagarae and Scenedesmus ecornis (Fig.
17c) had geographical abundance patterns with maxima in the central
basin. Only Peridinium aciculiferum and Staurastrum paradoxum were
more abundant in the eastern basin.
Numerically, phytoplankton abundance was greater in the western
basin (Fig. 8). Biomass was also greatest in the western basin in
April, May and June. However, for the study period, average biomass
was similar in the western and central basins (Table 21). This
contradiction was due to the greater abundance being caused, in part,
by the greater abundance of Anacystis marina in the western biomass
which contributed little to the biomass because of its small size.
However, numerically the Bacillariophyta, Chlorophyta, Chrysophyta and
Cryptophyta all possessed a general pattern of decreasing abundance
from west to east for the study period.
Indicator Species
Munawar and Munawar (1982) concluded that the species of
phytoplankton found in 1970 usually occurred in mesotrophic and
eutrophic conditions. In 1983 a similar conclusion could be drawn
even though algal biomass had decreased substantially (see next
section). Common species included eutrophic indicators (Fragilaria
-------
capucina, Melosira granulata, Peridinium aciculiferum, Pediastrum
simplex, Scenedesmus ecornis) and mesotrophic indicators
(Stephanodiscus niagarae, Fragilaria crotonensis, Tabellaria
flocculosa).
A mesotrophic-eutrophic designation agreed reasonably well with
the trophic status as determined by the biomass classification scheme
of Munawar and Munawar (1982), With a mean biomass of 1.36 g/m
for the study period for the entire lake, Lake Erie would be
classified as mesotrophic.
Historical ChanRes in Community Biomass
A very large and consistent increase in the total quantity of
phytoplankton in the central basin occurred between 1927 and 1964
(Davis 1964, 1969b). From 1967 to 1975 a decline in the nearshore
phytoplankton of the western basin was evident (Nicholls et al.
1977b). Similarly from 1970 to 1980, a number of the common species
had decreased in biomass (Table 20), and the total phytoplankton
biomass for all three basins had decreased dramatically (Fig. 53).
The historically highly productive western basin (Munawar and Burns
1976) has had, in particular, a steady decrease in biomass from 1958
to 1983 (Table 22). In fact, the 1983 mean biomass for the western
basin was similar to the central basin (Table 21). The decrease
appears to be correlated with reductions in phosphorus loading when
average phosphorus loading from the Detroit River in western Lake Erie
decreased from about 75 metric tons/day during the 1968-1970 period to
about 35 metric tons/day by the early 1970's and was further reduced
during 1970 and 1979 (Nicholls 1981, Great Lakes Water Quality Board
1974, Yaksich et al. 1985).
-------
LAKE HURON
Changes in Species Composition
The literature pertaining to phytoplankton of the offshore waters
of Lake Huron is sparse. Fenwick (1962, 1968) published some
qualitative data, and Parkos et al. (1969) listed species observed.
Quantitative data from a single offshore station from 1971 exists
(Munawar and Munawar 1982, Vollenwider et al. 1974). Stoermer and
Kreis (1980) reported on an extensive sampling program in southern
Lake Huron including Saginaw Bay during 197A and provided an extensive
bibliography on Huron algal research. An intensive study of the
entire lake basin was performed in 1980 (Stevenson 1985).
Since 1971 diatoms have been the dominant division. Dominant
diatoms in 1971 included species of Asterionella formosa, A.
gracillima, Cyclotella comta, C. glomerata, C. ocellata. C.
michiganiana. Melosira islandica and M. granulata. In addition,
species such as Fragilaria crotonenis and Tabellaria fenestrata were
common, while cryptomonads, such as Rhodomonas minuta and Cryptomonaa
erosa, contributed very heavily during different seasons.
The following similar common diatoms were observed in 1974 and
1983: Asterionella formosa, Cyclotella comensis. C.
michiganiana. C. ocellata, Fragilaria crotonensis, Tabellaria
fenestrata. T. flocculosa var. linearis and Rhizosolenia sp..
Cyclotella stelligera and Synedra filiformis were present in 1983
but were not as common as the 1974 southern Lake Huron plus Saginaw
Bay data. Melosira islandica was more prevalent in 1983 than in the
1974 data base.
Both Cryptomonaa erosa and Rhodomonas minuta var.
nannoplanktica were dominant in 1971, 1974 and 1983. Dominant
-------
chrysophytea in 1971 were Dinobryon divergecs and Chrysosphaerella
longispina. In 1983 these two species were common along with D.
cvlindricum and JD. sociale var. americanum (Table 6). Haptophytes
were also numerically abundant. In general, C. stelligera and
Synedra filiformis decreased in abundance after 197A, while M.
islandica, D. cylindricum and D. sociale var. americanum have
increased in abundance.
Picoplankton
The autotrophic nature of picoplankton has been brought to the
attention of phycologists in recent years (Johnson and Sieburth 1979,
1982; Li et al. 1983). In the Great Lakes, Sicko-Goad and Stoermer
(1984) presented the first evidence of picoplankton in the Great
Lakes, while Caron et al. (1985) documented the occurrence of
photosynthetic chroococcoid cyanobacteria (0.7 - 1.3 fxm in diameter)
in Lake Ontario. The overwhelming dominance of picoplankton (probably
Anacystis marina and Coccocholoris peniocystis, Table 7) in the 1983
samples is of interest. Density in Lake Huron ranged from*>6 x
^ 10*
to * * cells/mL, which was lower but comparable to
3
picoplankton abundance in eutrophic Lake Ontario (range =~1 x 10
3
to 6.5 x 10 cells/mL) (Makarewicz 1985). Both Stoermer and Kreis
(1980) and Munawar and Munawar (1982) did not report these species.
It is reasonable to assume that previous workers ignored this
small-sized fraction when enumerating phytoplankton, believing them to
be bacterial in nature.
PoB^Pimt and Indicator Species for the Entire Lake
Dominant diatoms in Lake Huron in 1983 were Rhizosolenia sp. and
-------
Tabellara flocculosa (biomass) and Cyclotella comensis
(numerically). Four species of Cyclotella (C. comensis. C. comta.
C. kuetzingiana var. planetophora and C. ocellata) represented 9.47%
of the total biomass (Table 7). Except for C. comensis, whose
ecological affinities are poorly understood (Stoermer and Kreis 1980),
these species are associated with oligotrophic or mesotrophic
conditions. Similarly. Tabellaria flocculosa is commonly associated
with mesotrophic conditions (Tarapchak and Stoermer 1976).
Dominant chrysophytes included Dinobryon sociale var.
americanum, D. divergens and D. cylindricum, which are often
associated with several small members of the genus Cyclotella
(Schelske et al. 1972, 1974) included in the classical oligotrophic
diatom plankton association of Hutchinson (1967). Dominant
cryptophytes, cyanophytes and dinoflagellates were Rhodomonas minuta
var. nannoplanktica. Cryptomonas erosa, Anacystis marina and
Ceratium hirundinella.
Because of the limited number of studies of the Lake Huron
offshore phytoplankton assemblage, there was also a limited basis for
evalutating long-term effects of eutrophication. Those studies
available (Nicholls et al. 1977a, Schelske et al. 1972, 1974)
indicated that the waters of northern Lake Huron generally contained
phytoplankton assemblages indicative of oligotrophic conditions. The
designation of the offshore waters of southern Lake Huron as
oligotrophic based on phytoplankton composition in 1983 was not unlike
the trophic statue suggested by Stoermer and Kreis (1980) for the
offshore waters in 1974. This agreed reasonably well with the trophic
status as determined by the biomass classification scheme of Munawar
and Munawar (1982). With a mean biomass of 0.38 g/m (range =
-------
97
0.14 to 0.75) for the study period. Lake Huron would be classified as
oligotrophic.
North-South Distribution
Regional variation in water quality was indicated by standing
crop and species composition. The mean phytoplankton abundance for
the sampling period decreased from north to south to Station 15 (Fig.
10). At Station 15 in southern Lake Huron, abundance increased and
remained high into the extreme southern end of Lake Huron. Much of
this geographical pattern was determined by the high numerical
abundance of Anacystis marina.
The north-south pattern still existed, however, when biomass was
considered. The diatoms, in particular, had a similar geographic
pattern accounting for much of this increase in the northern area
(Fig. 56). Diatoms having a distinctly higher abundance and biomass
at the northern stations were Asterionella formosa (Fig. 23a),
Cyclotella comensis, C. comta and C. ocellata. Other species
having a higher biomass in the northern stations were Coelosphaerium
naegelianum and Dinobryon sociale var. americanum. Except for C,
comensis, whose ecological affinities are poorly understood or known,
the other diatom species common in the north during blooms (C.
comta, C. ocellata. A. formosa) are associated with mesotrophic or
oligotrophic conditions.
Stoermer and Kreis (1980) suggested that local regions in the
northern part of the lake may have shown the effects of nutrient
stress. However, these regions did not appear to develop the
populations tolerant of highly eutrophic conditions. Our data also
suggest that eutrophic conditions were not found. However, the higher
-------
biomass and the greater prevalence of Asterionella formosa at the far
northern stations suggested a more productive status for the northern
region. This may be caused by transport of the more productive waters
of Lake Michigan into Lake Huron. The physical transport of
populations by water currents from Lake Michigan into Lake Huron
through the Straits of Mackinac has been demonstrated (Schelske et al.
1976).
The higher abundance of phytoplankton (Fig. 10), especially the
higher biomass south of Saginaw Bay, was the result of higher biomass
of diatoms in April and May. Diatoms with a higher biomass in this
region were Asterionella formosa, Cyclotella ocellata, Fragilaria
crotonensis, Melosira islandica, Rhizosolenia sp. and Tabellaria
flocculosa var. linearis. There are at least two possible causes for
the higher biomass observed in April and May south of Saginaw Bay:
(1) transport of plankton from the historically more productive
Saginaw Bay or (2) higher nutrient loading to southern Lake Huron.
Because of the sampling design of the 1983 study, it is impossibe to
evaluate transport. In prior years though, tranport from Saginaw Bay
affected mid-lake stations (Stoermer and Kreis 1980).
More recently, Stoermer and Theriot (1985) suggested that the
direct effects of phosphorus-stimulated phytoplankton overproduction
in Saginaw Bay on the rest of the Lake Huron ecosystem have been
substantially mitigated. In particular, the injection of
eutrophication-tolerant populations from Saginaw Bay to Lake Huron has
decreased. This suggests that other species tolerant of less
productive waters may currently be transported from the Bay to Lake
Huron. The 1983 phytoplankton composition of the southern basin
suggested a slight degradation of these waters from 1971. Stevenson
-------
(1985) concluded similarly in 1980. Further study and a different
sampling design would be necessary to evaluate the cause of the higher
biomass observed in southern Lake Huron in 1983.
Historical Changes in Community Abundance and Biomass
Quantitative phytoplankton data exist for the offshore waters of
Lake Huron from at least 1971. The collections of Stoermer and Kreis
(1980) were from 44 stations in southern Lake Huron and Saginaw Bay.
Phytoplankton were concentrated on millipore filters rather than by
the settling chamber procedure used in this study. Thus, the sets of
data were not strictly comparable. However, some patterns are
suggested (Fig. 54). Abundances in the early spring and late summer
and late summer/early fall of 1977 and 1983 were similar, but
abundances during late May and early July of 1983 were considerably
lower than those during 1974 in southern Lake Huron. It is difficult
to conclude whether these differences were apparent and due to
different enumeration techniques or were related to the decrease in
transport of phytoplankton from Saginaw Bay due to phosphorus
mitigation efforts (Stoermer and Theriot 1985).
Munawar and Munawar (1982) collected with a 20-m integrating
sampler from April to December of 1971. Because Utermohl's (1958)
procedure for enumeration of algae was employed, these data offered a
better comparison to the 1983 data. Seasonal biomass data for only
one offshore station of Lake Huron was available (Munawar and Munawar
1982) (Fig. 55). Average station biomass on all sampling dates in
1983 were lower than every sampling date in 1971. A comparison of the
maximum value of the range of the 1983 biomaas values on each sampling
date with the 1971 biomass data was strikingly similar. Also similar,
-------
loo
except at the low range, was the seasonal range of biomass values in
3
1971 (0.4 - 0.79 g/m ) (Munawar and Munawar 1982) and in 1983
3
(0.14 - 0.75 g/m ). Again the suggestion is an overall
improvement in water quality based on species composition and a
decrease in biomass. However, caution is required because of the
necessity to compare to one offshore station from 1971.
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101
LAKE MICHIGAN
Changes in Species Composition
Although an extensive literature on Lake Michigan phytoplankton
exists [see Tarapchak and Stoermer (1976) for a review to the earlier
literature], the establishment of long-term trends of phytoplankton in
the offshore waters is difficult due to the widely varying
methodologies employed. However, studies in 1962-63 and 1976-77 by
Stoermer and Kopczynska (1967a and b) and Rockwell et al. (1980),
respectively, utilized a settling chamber procedure similar to the
technique used in this study. The 1962-63 study was limited to the
southern basin, while the 1976-77 study is conservative in its
abundance estimate because a magnification of only 400x was used for
enumeration.
Division Trends
There is no doubt that diatoms have decreased in dominance in
Lake Michigan since the 1962-63 study. In the 1976-77 study,
phytoflagellates dominated at virtually all stations. In 1983 the
blue-greens dominated numerically by virtue of the high abundance of
the picoplankton which were not counted in previous studies. However,
in addition to the cyanophytes, both the cryptophytes and chlorophytes
were still numerically more important than the diatoms (Table 5) in
1983. The numerical decline of the diatoms is probably related to the
high phosphorus loading and concomitant silica depletion (Schleske and
Stoermer 1971}. On a biomass basis, however, diatoms were the
dominant group in 1983.
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102
Species Trends
Evaluation of changes in species is difficult because many of the
earlier workers did not report the abundances actually observed.
Qualitative comparisons were simply made. Dominant diatoms in 1983
included the numerically dominant Cyclotella comensis, Fragilaria
crotonensis and Melosira italica subsp. subarctica ; on a biomass
basis, Tabellaria flocculosa was predominant (Table 8). Of the 1983
dominant diatoms, only Fragilaria crotonensis and perhaps T.
flocculosa were major components of the diatom assemblage in 1962-63.
Stoermer and Kopczynska (1967a) noted taxonomic difficulties with
Tabellaria and noted that most populations of Tabellaria "are probably
to be referred to _T. fenestrata " The dominant species of
Cyclotella and Melosira in 1962-63 were C. michiganiana and M.
islandica.
Rockwell et al. (1980) reported that Cyclotella spp. were common
in 1977 but were never dominant. The dramatic decrease in some
species of Cyclotella, such as C. michiganiana and C_. stelligera.
which were offshore dominants in August of 1970, is presented in Table
23. C. comensis, believed to be tolerant of higher nutrient and
lower silica concentrations than most members of this genus, is
currently the numerically dominant diatom in the offshore.
A change in prevalence of species of Melosira was evident. M.
islandica was dominant in 1962-63. In 1983 M. islandica was present
(x = 12.1 cells/mL), but M. italica subsp. subarctica (x = 37.6
cells/mL) was more abundant. Similarly, Synedra acus was common
throughout the southern basin in 1977 (Rockwell et al. 1980) but in
1983 represented only 0.1Z of the total cells.
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103
K. eriensis had apparently declined in abundance. In May of
1962-63* relatively high (100 cells/mL) populations were observed in
southern Lake Michigan (Stoermer and Kopczynska 1967a). During May
and June of 1970, mean abundances for offshore stations were 63 and
611 cells/mL, respectively (Holland and Beeton 1972). Rockwell et al.
(1980) reported a mean density of 28.7 cells/mL for R. eriensis
during June of 1977. Abundance in 1983 was 2.6 cells/mL for the
entire lake. A bloom (133 cells/mL) in the far northern station
(Station 77) did occur in October.
Ankistrodesmus falcatus increased in abundance to 1977 and had
decreased by 1983. Ahlstrom (1936) reported it as rare, but Stoermer
and Kopczynska (1967a) noted that it had increased by 1962-63 (range =
20-60 cells/mL). Rockwell et al. (1980) suggested that by 1977 it had
increased further (range = 20-610 cells/mL). In 1983 this species was
observed only once during the study at Station 32 (6.5 cells/mL).
Dominant chrysophytes in 1962-63 were Dinobryon divergens. D^.
cvlindricum and D. sociale, which were also the common species in
1983. Rockwell et al. (1980) reported these species as dominant or
subdominant often in the offshore. D. sociale var. americanum was
the prevalent species of Dinobryon in 1983. However, the haptophytes
were numerically the dominant group.
Dominant cryptophytes included Cryptomonaa erosa var. reflexa,
C. erosa and Rhodomonas minuta var. nannoplanktica. Stoermer and
Kopczynska (1967b) and Stoermer (1978) reported these species as
uncommon in Lake Michigan, but Vollenweider et al. (1974) noted these
Bpeeies as commonly found. Similarly, Munavar and Munawar (1975),
Claflin (1975) and Rockwell et al. (1980) had reported C. eroaa and
r. minuta var. nannoplanktica to be dominant, abundant and perhaps
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104
increasing in number. From our 1983 study, it is apparent that C.
erosa was numerically uncommon but on a biomass basis was the second
most important cryptophyte (Table 8). Evaluation of abundance of R.
minuta in earlier studies was not possible because it was grouped into
phytoflagellates, flagellates or simply Rhodomonas. What can be said
about Rhodomonas minuta var. nannoplanktica is that in 1983 it was
the dominant cryptophyte on a numerical and biomass basis.
Oscillatoria limnetica has become more prevalent in the lake.
Ahlstrom (1936) and Stoermer and Kopczynska (1967a) listed 0.
mougeotii as the only species of this genus abundant in their
collections. Stoermer and Ladewski (1976) reported that 0. limnetica
had generally increased in abundance in Lake Michigan. Rockwell et
al. (1980) observed that 0. limnetica was common throughout the basin
in April and June and was especially abundant in September of 1977 at
certain stations. Not considering the picoplankton, which were not
counted in previous studies, 0. limnetica was the dominant offshore
blue-green algae in 1983 (Table 8).
Picoplankton
The autotrophic nature of picoplankton has been brought to the
attention of phycologists in recent years (Johnson and Sieburth
1979,1982; Li et al. 1983). In the Great Lakes. Sicko-Goad and
Stoermer (1984) presented the first evidence of picoplankton, while
Caron et al. (1985) documented the occurrence of photosynthetic
chroococcoid cyanobacteria (0.7 - 1.3 jim in diameter) in Lake Ontario.
The overwhelming abundance of picoplankton (probably Anacystis marim
and Coccochloris peniocystis) (Table 8) in the 1983 samples is of
interest. Densities in Lake Michigan (x = 23,607; maximum of 1 x
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105
O
10 cells/mL) were comparable to the picoplankton densities in
3 3
Lake Ontario which ranged £rom ~1 x 10 to 6.5 x 10 cells/mL.
Mo other researchers on Lake Michigan have routinely reported these
species. It is reasonable to assume that previous Great Lakes'
workers, believing the picoplankton to be bacterial in nature, ignored
this small-sized fraction when enumerating phytoplankon.
Indicator Species
A comparison of modern and historic records by Stoermer and Yang
(1970) indicated that taxa characteristic of disturbed situations are
rapidly increasing in relative abundance in Lake Michigan. In the
nearshore area, a shift in oligotrophic forms to forms which dominate
under eutrophic conditions was evident. Occurrence of certain
eutrophic forms were also evident in offshore waters (Stoermer and
Yang 1970). Dominant diatom species in the offshore waters in 1983
were Cvclotella comensis, C. comta, Tabellaria flocculosa,
Fraailaria crotonensis and Melosira italica subsp. subarctica. C.
comta, T. flocculosa and F. crotonensis are mesotrophic forms,
while the ecological affinities of C. comensis and M. italica are
poorly understood.
North-South Distribution
Regional variation in water quality was indicated by the
geographical variation in abundance and the variable species
composition. The mean station phytoplankton abundance for the
sampling period generally decreased from north to south with two small
peaks at Stations 41 and 6 at the most southern sampling point (Fig.
12) • Much of the increase was due to picoplankton abundance.
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106
However, diatoms, cryptophytes, chrysophytes and chlorophytes all had
higher abundances at the northern stations (Stations 77 and 64) and at
the southern station (Station 6). The peak at Station 41 was
primarily due to chrysophytes but also to cryptophytes and
chlorophytes.
Species having a distinctly higher abundance at the northern
stations were Tabellaria flocculosa, Tabellaria fenestrate.
Fragilaria vaucheriae. Fragilaria crotonensis, Cyclotella comta.
C. comensis, Chroomonas norstedtii, Oscillatoria agardhii and
Coelosphaerium naegelianum. Except for C. comensis. whose
ecological affinities are poorly known, the other diatom species
common at Stations 64 and 77 are generally associated with mesotrophic
conditions. The peak in abundance at Station 41 was primarily due to
haptophytes and Dinobryon cylindricum. Besides picoplankton, the
peak at Station 6 at the far southern end of the lake was due to
increases in Dinobryon sociale var. americanum, D. divergens and
species of haptophytes.
Species composition and abundance suggest that the far northern
stations, in particular, showed some indication of nutrient stress.
There are at least two possible causes for the higher biomass observed
north of Green Bay: higher nutrient loading to these northern waters
and the transport of plankton from the historically more productive
Green Bay. Because of the sampling design of the 1983 study, it is
impossible to evaluate transport. Hater that does escape the bay most
commonly flows south along the Wisconsin shore. However, high
conductivity values in north-central Lake Michigan have been
attributed to Green Bay (Stoermer and Stevenson 1980). Also,
substantial exchange may exist because the Bay de Noc complex alone
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107
has been estimated to contributed 12% of the total phosphorus loaded
to Lake Michigan (Upchurch 1972).
Historical Changes in Community Abundance
A comparison of abundance trends over the entire lake was not
possible because of the non-availability of comparable offshore data
prior to 1983. A reasonably valid comparison can be made of the
offshore of the southern extreme of Lake Michigan from 1962-63 to
1976-77 to 1983. From 1962-63 to 1976, abundance appeared to increase
(Table 24) with Rockwell et al. (1980) reporting a conservative
Bff*4«nni density of **>6,000 cells/mL.
Because picoplankton were not counted in previous years, they
hove been removed from the 1983 data allowing comparison to previous
years (Table 24). Abundance was higher in 1983 than in 1962-63 but
sinilar to the abundance in 1976. This observation confirms that an
increase has taken place since 1962-63. Because of the conservative
nature of the 1976 abundance data, the suggestion could be made that
abundances decreased from 1976 to 1983. However, there is no evidence
to substantiate the suggestion.
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108
DISCUSSION
ZOOPLANKTON
LAKE ERIE
Changes in Species Composition
Brooks (1969) suggested that a shift in the Lake Erie cladoceran
assemblage was evident by 1948-49 with smaller cladocerans, such as
Daphnia galeata mendotae, D. retrocurva and Diaphanosoma. being
more abundant than in 1938-39. In 1970 the most commonly found
Daphnia species were J). retrocurva, D. galeata mendotae and D.
longiremis (Watson and Carpenter 1974). However, Bosmina
longirostris and Eubosmina coregoni were more abundant (Watson and
Carpenter 1974). Predominant cladoceran species in 1983 were small
forms similar to those observed in 1970. In 1983 the predominant
Cladocera in descending order were Eubosmina coregoni, Daphnia
galeata mendotae, Daphnia retrocurva, Bosmina longirostrisT
Diaphanosoma leuchtenbergianum and Chydorus sphaericus (Table 11).
Chydorus sphaericus has established itself as a common species
in Lake Erie. A rare species in the offshore waters of the western
basin in 1929-30 (Tidd 1955), this species was a prominent constituent
in the 1950's (Davis 1962) and in 1970 with a higher abundance in the
western basin (Watson and Carpenter 1974). In 1983 this species
contributed only 0.2% of the total abundance and had no observable
abundance peak in the western basin.
Cyclops vernalis has exhibited a dramatic increase in abundance
and distribution (Gannon 1981). In the 30's, C. vernalis was found
only in the extreme western end of Lake Erie at the mouth of the
Detroit and Maumee Rivers (Tidd 1955)» By 1967 it had spread
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109
throughout the lake (Davis 1969a). Patalas (1972) and Watson (1976)
reported it as numerous in the western basin of Lake Erie during the
late 60's and 70's. In 1983 C. vernalis was not observed at any of
the sampling stations.
The dominant cyclopoid copepod in 1970 was Cyclops bicuspidatus
thomasi with Mesocyclops edax common in the summer. Tropocyclops
prasinus was present in low numbers (Watson and Carpenter 1974). In
1983 the same three species ( C. bicuspidatus thomasi. M. edax and
T. prasinus ) predominated (Table 11).
Abundance of Diaptomus siciloides has increased in Lake Erie
(Gannon 1981). It was most prevalent in the western basin and western
portion of the central basin in the late 60's and 70's (Patalas 1972,
Watson 1974). Abundant diaptomids in the eastern and central basins
in 1970 were Diaptomus oregonensis and D^. siciloides. D^.
oregonensis and D. siciloides were also the predominant calanoids in
Lake Erie in 1983. In 1983 D. oregonensis was more prevalent in the
central and eastern basins, while D. siciloides was more prevalent in
the eastern and western basins.
Davis* studies (1968, 1969a) of the zooplankton of Lake Erie did
include rotifers. Certain soft-bodied rotifers were not identified
nor are the samples quantitative for rotifers. A #20 net was
employed. However, it is apparently the only lake-wide study of the
offshore that included the rotifers. Species observed to be abundant
in 1967 were Brachionus angularis, B. calyciflorus, Conochilus
unicornis, Keratella cochlearis. K. quadrata, Kellicottia
longispina, Synchaeta stylata and Polyarthra vulgaris (Davis 1968,
1969a). In 1983 a similar group of abundant rotifers was found. In
decreasing order of relative abundance (% of total abundance), the
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110
abundant species were: Polyarthra vulgaris (18.4%), Synchaeta sp.
(9.5%), Keratella cochlearis (7.3%), Conochilus unicornis (5.3%),
Keratella hiemalis (3.5%), Brachionus sp. (3.0%), etc. (see Table
11). Although it was only the fourteenth most abundant rotifer,
Kellicottia longispina was still prevalent in 1983 representing 1.3%
of the total abundance (Table 11). Only Keratella quadrate is
apparently not as abundant in 1983 as it was in 1967. K. quadrata
was observed in 1983 but was not common ( <1% of total abundance).
East-West Species Distribution
Numerous researchers (e.g. Davis 1969a, Watson 1974, Patalas
1972, Gannon 1981) have documented the existence of differences in
species composition and abundance from the central, western and
eastern basins. In 1983 at least 13 species had higher abundances or
distributions restricted (see Indicator Species) to the western basin
(Table 25). Five species Diaptomus oregonensis (Fig. 39a), Cyclops
bicuspidatus thomasi (Fig. 39b), Colletheca sp., Kellicottia
longispina and Keratella hiemalis (Fig. 42b) had geographical
abundance patterns with maxima in the central basin. Only the
cyclopoid Tropocyclops prasinus mexicanus was more prevalent in the
eastern basin. From Fig. 39c, a west to east buildup in T. prasinus
is evident. Both Daphnia galeata mendotae and Mesocyclops edax were
abundant in the eastern and central basins.
Indicators of Trophic Status
Zooplankton have potential value as assessors of trophic status
(Gannon and Stemberger 1978). Rotifers, in particular, respond more
quickly to environmental changes than do the crustacean plankton and
-------
Ill
appear to be more sensitive indicators of changes in water quality
(Gannon and Stemberger 1978). Brachionus angular is, B.
calyciflorus, Filinia longiseta and Trichocerca multicrinis are
four rotifer species indicative of eutrophy. Species in the genus
Brachionus are particularly good indicators of eutrophy in the Great
Lakes (Gannon and Stemberger 1978).
The eutrophic rotifers Brachionus caudatus, Brachionus sp.,
Filinia longiseta, Synchaeta sp., Trichocerca cylindrica,
Trichocerca multicrinis and Keratella earlinae had abundances
restricted to or significantly higher in the western basin (Figs. 40b
& c; 41a,b & c; 42a & c). Total zooplankton abundance was also higher
in the western basin. Both rotifer abundance and species composition
indicated a greater degree of eutrophy of the western basin than of
the central or eastern basins.
The calanoid/cyclopoid plus cladoceran ratio (plankton ratio) has
been employed as a measure of trophic condition in the Great Lakes
(Gannon and Stemberger 1978, McNaught et al. 1980). Calanoid copepods
generally appear best adapted for oligotrophic conditions, while
cladocerans and cyclopoid copepods are relatively more abundant in
eutrophic waters (Gannon and Stemberger 1978). In Lake Erie this
ratio increased from west to east (Table 26). The productive status
(primary production) of the western basin as compared to the central
and eastern basins (Glooschenko et al. 1974a, Glooschenko 1974b) was
correlated in the abundance of zooplankton, species composition and
the calanoid to cyclopoid plus cladoceran ratio. Compared to Lakes
Huron and Michigan in 1983, abundance of zooplankton was greatest, and
the plankton ratio was lower in Lake Erie (Table 19) indicating the
eutrophic nature of Lake Erie.
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Historical Changes in Abundances
Zooplankton data exists for the western basin of Lake Erie from
1939 to 1983. Gannon (1981) noted that the collections in 1939, 1949
and 1961 were made with a 10-liter Juday trap in the islands region,
and the 1970 collections were obtained at the extreme western end of
the lake with an 8-liter Van Dorn bottle. The data were not strictly
comparable with each other or the 1983 data. In particular, the 1970
data were from the far western end of the western basin and probably
are not representative of the entire western basin. Also, samples
from the late spring to the early summer and from the late summer of
1983 were lacking, but some trends were suggested.
In comparing the 1970 data to the 1939, 1949 and the 1961
zooplankton data, Gannon (1981) concluded that an increase occurred in
the cladocerans, copepods and rotifers of the western basin of Lake
Erie. However, a comparison to the 1983 August data for Cladocera and
Copepoda suggested that abundances were more comparable to the 50's
(Figs. 58 and 59). Cladocera data from October suggested a slighly
higher abundance in 1983 than in previous years. Without sampling
points in June, July and September at times of zooplankton maxima in
Lake Erie, no firm conclusions could be made on crustacean
populations. The increase in numbers of rotifers was sufficiently
large and consistent to indicate an abundance increase from 1970 to
1983 (Fig. 60).
Watson and Carpenter (1974) utilized a 64-jim mesh net in 1971 to
collect vertical hauls of zooplankton from the entire lake basin.
These data are comparable to 1983 collections and are presented in
Fig. 57. Again, the lack of a sampling point between mid-May through
-------
July did not allow a comparison during what was the peak abundance
period of zooplankton In 1970. However, the Apr 11-May and
August-October periods were comparable and suggested that total
zooplankton abundance was similar from 1970 to 1983 during those
periods.
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114
LAKE HURON
Changes in Species Composition
Crustacean studies of the entire Lake Huron basin are few in
number. Patalas (1972) sampled 51 stations including Saginaw Bay in
August of 1968 with a 77-jim mesh net. In 1971, eleven stations on a
transect from the Straits of Mackinac to the origin of the St. Clair
River were sampled from May to November with a 64-jim net (Watson and
Carpenter 1974). A 64-ju mesh net was used to sample 18 stations on
eight dates from April to October of 1974 in southern Lake Huron
including Saginaw Bay (McNaught et al. 1980). The 1983 research
included 10 stations sampled (62-jim mesh net) for each of the three
sampling dates between August and September.
In August of 1968 calanoids were dominated by Diaptomus sicilis,
D. ashlandi and D. minutus (Patalas 1972). These same three species
were dominant in 1971, 1974/75 and 1983 with the addition of Diaptomus
oregonensis (Table 27). Although not strictly comparable, mean
abundance for the major calanoid species were similar for the 1971 and
1983 samples. The 1974 calanoid abundance was higher than either the
1971 or 1983 samples. However, the 1971 and 1983 data were only from
offshore sites, while 1974 data included samples from the eutrophic
waters of Saginaw Bay. The oligotrophic indicator species,
Limnocalanus macrurus, appeared to be decreasing in abundance (Table
27).
In 1968, 1971, 1974/75 and 1983, the dominant cyclopoid was
Cyclops bicuspidatus thomasi (Table 27). Tropocyclops prasinus
mexicanus and Mesocyclops edax appeared to have increased in
abundance from 1971 to 1983. Cyclops vernalis. often associated with
eutrophic conditions in Lake Erie, was higher in abundance in the 1974
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115
data. This higher abundance again may have been due to the inclusion
of Saginaw Bay stations in the 1974 data set.
Dominant cladoceran species in August of 1968 were Bosmina
longirostris and Holopedium gibberum, while in 1974 Holopedium
gibberum, B. longirostris and Eubosmina coregoni were dominant in
August-October. Comparison of the 1971 and 1983 August data suggested
decreases in abundance of B. longiroatris, E. coregoni and H.
gibberum.
Quantitative data on species of daphnids were not available for
1971, but Daphnia retrocurva, Daphnia galeata mendotae and D.
longiremis were commonly found in Lake Huron (Watson and Carpenter
1974). The dominant daphnid species in 1983 was I). galeata
mendotae.
Evans (1985) recently reported that Daphnia pulicaria was a new
species dominating Lake Michigan. In 1983 in Lake Huron, D.
pulicaria was observed to be the third most important cladoceran
(Table 12). Mean station abundance increased from north to south with
3
a mean density of 431 organisms/m for stations south of Saginaw
Bay.
D. catawba also appeared to be a new dominant from the deeper
waters of Lake Huron. This species was not thought to be either
common or less common species of the Great Lakes (Balcer et al. 1984).
It appeared exclusively in the long hauls from Lake Huron in 1983. A
3
mflvimiim abundance of 1,610 organisms/m was observed in August at
Station 12.
Stemberger et al. (1979) collected rotifers with a Nisken bottle
at 5-m intervals to 20m followed by 10-m intervals to the bottom of
the lake. Samples were pooled and filtered through a 54->i mesh net on
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116
the vessel. Greatest abundance of rotifers in Lake Huron in 1974
occurred in late spring and early summer (Stemberger et al. 1979), a
period in which no samples were taken in 1983. Comparison of the
August-October of 1983 to April-November of 1974 suggested the
following between the 1974 and 1983 data. Abundant rotifer species in
both studies were Conochilus unicornis, Polyarthra vulgaris.
Keratella cochlearis, Kellicottia longispina and Gastropus
stylifer. C. unicornis was the dominant rotifer in 1983 while
Keratella cochlearis was dominant in 1974 (Table 29).
North-South Distribution
Horizontal distribution of zooplankton in Lake Huron is affected
by the physical limnology of the lake (McNaught et al. 1980). In the
warmer inshore areas, cladocerans grow best, while calanoids tend to
be found in offshore waters (McNaught et al. 1980). Movement of the
zooplankton-rich eutrophic waters from Saginaw Bay also influenced
zooplankton abundance in the nearshore waters of Lake Huron south of
the Bay. In general, inshore densities were greater than offshore
densities (McNaught et al. 1980).
The 1983 data did suggest a trend of increasing total zooplankton
abundance from south to north (Fig. 33) with the exception of Station
32, located northeast of the mouth of Saginaw Bay. However, Station
32 would appear to be too far offshore to be influenced by the higher
abundances of the Bay. However, Stoermer and Kreis (1980) have
observed midlake stations in southern Lake Huron to be affected by
populations of phytoplankton from Saginaw Bay in 1974. Although the
transport of eutrophication-tolerant algal populations into Lake Huron
from Saginaw Bay has been mitigated in recent years (Stoermer and
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117
Theriot 1985), the transport of zooplankton could still take place.
Total abundance was slightly higher in the extreme south at
Stations 9 and 6 due to increases in rotifer, cyclopoid and copepoda
nauplii abundances. McNaught et al. (1980) also observed abundance
increases of the cyclopoid copepodites, C_. bicuspidatus and T^.
prasinus north to south in southern Lake Huron. In 1983 rotifers
decreased in abundance from north to south to Stations 9 and 6 when a
slight increase was evident (Fig. 33).
A number of species possessed horizontal distributions that
varied along the north-south axis. Diaptomus minutus abundance was
lower in the northern portion of the lake (Fig. 46a), while Daphnia
retrocurva had a maxima limited to the far northern station (Fig.
46b). Abundance of both Conochilus unicornis and Kellicottia
longispina decreased from north to south. Holopedium gibberum had a
higher abundance north of Saginaw Bay, while Mesocyclops edax
abundance was higher south of Saginaw Bay. Cyclops bicuspidatus
thomasi was more abundant at the far northern stations (Stations 51
and 64) than in the rest of the lake.
Indicators of Trophic Status
Zooplankton have potential value as assessors of trophic status
(Gannon and Stemberger 1978). Rotifers, in particular, respond more
quickly to environmental changes than do the crustacean plankton and
appear to be more sensitive indicators of changes in water quality.
Composition of the rotifer community, as well as species, have been
employed to evaluate trophic status. A rotifer community dominated by
Polyarthra vulgaris, Keratella cochlearis, Conochilus unicornis
and Kellicottia longispina have been considered to be indicative of
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118
an oligotrophic lake (Gannon and Stemberger 1978). Even during a
period when rotifers were not abundant, these were the dominant
rotifers in Lake Huron from August to September of 1983 (Table 12).
The calanoid/cyclopoid plus cladoceran ratio (the plankton ratio)
has been employed as a measure of trophic status in the Great Lakes
(Gannon and Stemberger 1978, McNaught et al. 1980). Calanoid copepods
generally appear best adapted for oligotrophic conditions, while
cladocerans and cyclopoid copepods are relatively more abundant in
eutrophic waters. Using this ratio, McNaught et al. (1980) identified
the offshore waters of southern Lake Huron to have the highest quality
water. Because the 1983 samples were all from the-offshore, no such
comparison could be made. However, the plankton ratio was high and
similar from north to south (Table 28) indicating a similar high water
quality over the entire lake except for the far northern Station 61.
The low zooplakton abundance, compared to those of Lakes Erie and
Michigan (Table 19), the presence of the oligotrophic rotifer
association, the domination of the calanoids, and the fairly abundant
presence of the oligotrophic Diaptomus sicilis (McNaught et al. 1980)
suggested oligotrophic offshore waters for Lake Huron in 1983.
The lower ratio for Station 61 reflected the higher population of
Daphnia retrocurva in this area. This station might have been
influenced by waters from Lake Michigan. The plankton ratio at
Station 61 in Lake Huron was similar to that of the Straits of
Mackinac (Schelske et al. 1976) and northern Lake Michigan (see
Zooplankton, Lake Michigan).
Historical Changes in Abundances
Little can be concluded on quantitative changes in zooplankton
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119
because of the lack of data for the period early May to August* 1983.
Maximum zooplankton abundance occurred during this period in 1974
(Fig. 61). In comparing mean seasonal abundance patterns in 1972 and
1983, densities in August and October of 1983 were similar to those in
1972 (Fig. 61). The higher abundance of crustaceans in 1974 is
probably due to the inclusion of Saginaw Bay samples with this data
set.
Rotifer densities were more perplexing. Abundance was an order
of magnitude higher in 1974 than in 1983 (Table 29; Fig. 62). At
present* no explanation for such a difference can be provided.
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LAKE MICHIGAN
Changes in Species Composition
Numerous studies (Williams 1966; Johnson 1972; Gannon et al.
1982a, 1982b; Evans et al. 1980) of the nearshore region of Lake
Michigan exist from as far back as 1927 (Eddy 1927). Several
researchers have compared the nearshore with the offshore zooplankton
in discussions of eutrophication of the entire lake. Comparisons of
the inshore with the offshore stations should be viewed with caution
because effects are not necessarily due to eutrophication or fish
predation (Evans et al. 1980).
Although no intensive zooplankton studies of the offshore waters
of the entire lake basin have taken place, some offshore studies of
Lake Michigan zooplankton do exist. Wells (1960, 1970) sampled
Crustacea on four dates in June, July and August in 1954, 1966 and
1968 from the offshore region off Grand Haven, Michigan, with a #2
(366 jim) net. During 1969-70 on six dates (March 1969 to January
1970), Gannon (1975) collected crustaceans from the offshore and
inshore of Lake Michigan along a cross-lake transect from Milwaukee to
Ludington with a 64-jim mesh net. In September of 1973, northern Lake
Michigan was sampled with a 250-jim mesh net (Schelske et al. 1976).
Also, Stemberger and Evans (1984) provided abundance data (76-jim net)
for a few zooplankters from offshore waters of the southeastern Lake
Michigan area.
The data of Wells' (1960, 1970) and Gannon (1975) are useful but
have to be used with caution. A 366->im and a 250-jim net are probably
quantitative for larger crustaceans but certainly would not be for
smaller crustaceans such as Chydorus sphaericus, Bosmina
longirostris, Eubosmina coregoni, Ceriodaphnia spp., Tropocyclops
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121
prasinus, cyclopoid and calanoid copepods (Makarewicz and Likens
1979).
The zooplankton populations in Lake Michigan underwent striking
size-related changes between 1954 and 1966 (Wells 1970). Species that
declined sharply were the largest cladocerans (Leptodora kindtii,
Daphnia galeata mendotae and D. retrocurva) , the largest calanoid
copepods (Limnocalanus macrurus, Epischura lacustris and Diaptomus
sicilis) and the largest cyclopoid copepod (Mesocyclops edax).
Medium-sized or small species (I). longiremis, H. gibberum,
Polyphemus pediculus, Bosmina longirostris, Ceriodaphnia sp.,
Cyclops bicuspidatus, Cyclops vernalis. Diaptomus ashlandi)
increased in number, probably in response to selective alewife
predation. After the alewife dieback, M. edax and D. galeata
mendotae were still rare in 1968 when the composition of the
zooplankton community shifted back toward one similar of 1954 (Wells
1970).
In northern Lake Michigan during September of 1973, predominant
species were Daphnia galeata mendotae, D. retrocurva,
Limnocalanus macrurus. Diaptomus oregonensis, Eubosmina coregoni
and Diaptomus sicilis. Cyclopoid copepods were a minor component of
the fauna in 1973 (Schelske et al. 1976).
The changing nature of the zooplankton community of Lake Michigan
was further evident in 1983. Daphnia galeata mendotae, D.
pulicaria and J). retrocurva were the second, third and fourth most
important cladocerans in the lake (Table 13). Abundances of D.
galeata in August of 1983 were half of those in 1954 (1,200/m )
(Table 30). Perhaps as important, densities as high as 2,700/m
were observed at certain stations in August. Abundance of the large
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122
cladoceran Leptodora kindtii in 1983 was similar to abundance in
1954.
The 1983 abundance of Daphnia retrocurva was similar to the
August 1966 abundance rather than to those of 195A or 1968. However,
3
maximum abundance in October of 1983 (3,161/m ) was comparable to
the 1954 or 1968 observations. Perhaps related to the low abundance
of D. retrocurva in August of 1983 was the appearance of the large
(»-2 mm) (Evans 1985) cladoceran Daphnia pulicaria. which reached a
maximum abundance in August.
Evans (1985) recently reported that ,D. pulicaria was first
observed in Lake Michigan in 1978. Abundance remained low in
southeastern Lake Michigan until 1982 and 1983, when they dominated
the offshore summer Daphnia community and at an offshore station
southeast of Grand Haven, Michigan. In 1983 this species was the
dominant cladoceran in Lake Michigan from the short and long hauls
3
(Table 13). Mean abundance reached 1,741 organisms/m in early
3
August with a maximum of 6,056/m . Daphnia dubia, another new
species for the lake, had a mean station abundance of 49
3
organisms/m in early October.
Eubosmina coregoni, B. longirostris and the larger Holopedinm
gibberum appeared to have increased in abundance since 1954 (Table
30). The increase in H. gibberum was probably real. It is doubtful
that this large cladoceran would pass through a 366->im mesh net like
that used in Wells' (1960, 1970) studies of 1954-68. However, the net
employed by Wells' would not have been quantitative for E. coregoni
and B. longirostris.
Cyclops bicuspidatus was the dominant cyclopoid with Diaptomus
ashlandi being the dominant calanoid in 1983. Abundance of
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123
Mesocyclops edax was low in August of 1983 compared to 1954, but
abundance in early October reached 151 organisms/m (mean station
abundance). Diaptomus minutus appeared to have decreased in
abundance since 1968 while there was some suggestion that D.
oregonensis had increased steadily since 1954 (Table 31). D. sicilis
had increased dramatically since 1968. Abundance of Limnocalanus
macrurus was lower during August of 1983 than in 1954-68, However*
abundance in April of 1983 was 1,724/m . The abundance of
Epischura lacustris in August was still low in 1983 relative to 1954,
3
but mean station abundance was 111 organisms/m in late October.
By 1983 the large cladocerans, calanoids and cyclopoid copepods,
observed by Wells (1970) to have decreased sharply in the early 60's,
had increased in abundance to denities similar to those in August of
1954. In some instances, abundance was not as high in August but was
as high at other times of the year. In addition, two new species were
observed including the large and now dominant Daphnia pulicaria.
The resurgence of larger zooplankton in Lake Michigan is probably
related to the sharp decline in the abundance of the planktivorous
alewife in 1982 and 1983. The lakewide catch of adult alewifes was
only 31% that of 1982 and only 12% of the 1981 catch. Bloater chubs
are replacing the alewifes and have been experiencing a dramatic
increase in abundance since 1970 (Wells and Hatch 1983). Bloaters
above w18 cm in size primarily feed on Mysis and Pontoporeia. Only
smaller individuals feed on zooplankton (Wells and Beeton 1963).
Rotifera
Rotifer studies reported in the literature are primarily from the
nearshore region of the lake. In the nearshore, Keratella
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124
cochlearis, Polyarthra vulgaris, Kellicottia longispina.
Synchaeta stylata and Synchaeta tremula were dominant in 1926-27
(Eddy 1927). Keratella and Polyarthra were the dominant genera in
1962 (Williams 1966), while JK. cochlearis and P. vulgaris were
dominant in 1970 (Johnson 1972). Gannon et al.(1982a) noted that the
following rotifers were predominant in 1977: K. cochlearis, K.
crassa, P_. vulgaris, Conochilus unicornis, K. longispina and P.
remata.
Abundance of rotifers in Lake Michigan generally decreased from
the nearshore into the offshore (Gannon et al. 1982a* Stemberger and
Evans 1984). It is also of interest that the species composition of
the nearshore and offshore was similar. In 1983 the predominant
offshore rotifers were in descending order: Polyarthra vulgaris,
Synchaeta sp., Keratella cochlearis, Polyarthra major, Kellicottia
longispina, Keratella crassa, Gastropus stylifer and Colletheca
sp. (Table 13), which are similar to nearshore and to Ahlstrom's
(1936) offshore observations of predominant species (IC. cochlearis.
Synchaeta stylata and vulgaris).
North-South Trophic Status
In comparison to Lakes Erie and Huron, the geographical
distributional pattern of total zooplahkton was erratic. This may be
related to the alteration of east-west sampling stations on every
other trip (see Methods and Materials). There was a suggestion of
decreasing zooplankton abundance from north to south (Fig. 34).
Rotifera, in particular, did decrease southward on the transect, while
the Calanoida had approximately twice the abundance in the southern
half (Stations 34 to 6) than in the northern half (Stations 77 to 41)
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125
of the lake. The distribution of the calanoid Diaptomus sicilis was
restricted essentially to the southern half of the lake (Fig. 51a).
3
Cladocera abundance ranged from 1,000-2,000 organisms/m except at
3
Station 64 where a mean abundance of 5,000/m was observed.
Geographical abundance of Eubosmina coregoni and Bosmina
longirostris had inverse distributional patterns from Limnocalanus
macrurus (Fig. 63). Also, Notholca laurentiae, N. squamula, N.
foliacea (Fig. 52a-c) and Holopedium gibberum all had abundance
peaks at the far northern end of the lake and were not abundant in the
southern half of Lake Michigan. Daphnia retrocurva was observed in
maximum abundance at the extreme southern end of the lake (Fig. 51c).
Indicators of Trophic Status
Zooplankton have potential value as assessors of trophic status
(Gannon and Stemberger 1978). Rotifers, in particular, respond more
quickly to environmental changes than do the crustacean plankton and
appear to be more sensitive indicators of changes in water quality.
Composition of the rotifer community (Gannon and Stemberger 1978), as
well as species, have been employed to evaluate trophic status. A
rotifer community dominated by Polyarthra vulgaris, Keratella
cochlearis, Conochilus unicornis and Kellicottia longispina have
been considered to be an association indicative of an oligotrophic
community by Gannon and Stemberger (1978).
In 1983 the six predominant rotifers in descending order of
relative abundance were P_. vulgaris, Synchaeta sp., K. cochlearis,
P. major, K. longispina and jC. unicornis. The 1983 rotifer
community appeared to be an oligotrophic association.
The high relative abundance of Diaptomus sicilis and
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126
Limnocalanus macrurus (Table 13), both oligotrophia indicators
(Gannon and Stemberger 1978. McNaught et al. 1980), also suggested
oligotrophic offshore conditions.
The calanoid/cyclopoid plus cladoceran ratio has been used as a
measure of trophic status in the Great Lakes (Gannon and Stemberger
1978, McNaught et al. 1980). Calanoid copepods generally appear best
adapted for oligotrophic waters, while cladocerans and cylopoid
copepods are relatively more abundant in eutrophic waters. On the
north-south transect, the plankton ratios were high and similar,
except at the far north and the southern extreme of the lake (Table
32). This distribution of the ratios suggested that the highest
quality water existed from Station 57 to Station 11. With a
zooplankton abundance between those of Lakes Erie and Huron (Table
19), the presence of the oligotrophic rotifer association, a plankton
ratio between those of Huron and Erie, the domination of the
calanoids, and the fairly abundant presence of the oligotrophic
indicator species, Diaptomus sicilis and Limnocalanus macrurus. Lake
Michigan's waters in 1983 are best characterized as
mesotrophic/oligotrophic.
The low plankton ratios (0.37 and 0.41) at the far northern end
of Lake Michigan (Stations 64 and 77) were very similar to those
observed in 1973 at the Straits of Mackinac (Gannon and Stemberger
1978). Gannon and Stemberger (1978) implied that more eutrophic
conditions existed within this area of a low calanoid to cladoceran
plus cyclopoid ratio. Abundance of the oligotropic Limnocalanus
macrurus and Diaptomus sicilis was significantly lower in these far
northern stations, while the eutrophic species Eubosmina coregoni and
Bosmina longirostris increased at the far northern stations (Fig.
-------
127
63). Similarly, the eutrophic rotifer species Notholca squamula. N.
laurentiae and N. folicacea were only abundant at the far northern
area. Several indicators suggest that the northern end of Lake
Michigan near the Straits of Mackinac have waters often associated
with eutrophic conditions.
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128
RECOMMENDATIONS
1. Because much of the historical data that exists is from the
spring and summer periods, samples for zooplankton should be taken
during the period of greatest population growth; i.e. late May, June
and July. The lack of zooplankton data during this period in 1983
compromised the use of the data set for historical comparisons.
Furthermore, as the scientific community becomes more interested in
food web relationships, zooplankton abundance and diversity during
periods of maximum abundance will become of interest.
2. The same stations need to be sampled routinely. The rotation
of sampling sites in Lake Michigan only complicated the analysis and
interpretation.
3. A better understanding of the nature of the picoplankton is
required for the Great Lakes. In the current work, the decision was
made to enumerate blue-green algae even though direct observation as
to the autotrophic nature of the organism was inconclusive.
Fluorescence microscopy failed to reveal the presence of chlorophyll
in the objects because iodine (Lugol's fixative) quences fluorescence.
Great Lakes' material, fixed with glutaraldehyde, on membrane filters,
subjected to fluorescence microscopy autofluoresced, suggesting
chlorophyll containing objects (Andresen 1985). Further research is
suggested as below.
a. Taxonomic identification of the picoplankton.
b. Appropriate preservation of samples to utilize
fluorescence microscopy and TEM examination for elucidation of
biochemical and structural characters.
c. Examination of the pigment distribution by size fraction
-------
129
- chlorophyll and phycobilins (Stewart and Farmer 1984).
d. Productivity based on size fractions.
e. Examination of the potential use of cyanobacterium as a
food source for rotifers. Caron et al. (1985) suggests that rotifers
and microflagellates may be important consumers.
-------
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Schelske, C.L., L.E. Feldt. M.S. Simmons and E.F. Stoermer. 1974.
Storm induced relationships among chemical conditions and
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Biological* chemical and physical relationships in the Straits of
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terminology concerning phytoplankton size fractions and examples of
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Stemberger, R.S. 1979. A guide to rotifers of the Laurentian Great
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600/4-79-021. 185 p.
Stemberger, R.S., J.E. Gannon and F.J. Bricker. 1979. Spatial and
seasonal structure of rotifer communities in Lake Huron.
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Stemberger, R.S. and M.S. Evans. 1984. Rotifer seasonal succession
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417-428.
Stevenson, R.J. 1985. Phytoplankton - composition, abundance and
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-------
136
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-------
137
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-------
138
TABLE 1.
in 1983.
Plankton sampling dates for Lakes Erie, Huron and Michigan
Lake
Cruise
Cruise Date
ERIE
1
2
3
4
5
6
7
4/25 - 4/26
5/9 - 5/10
6/27 - 7/1 *
8/6 - 8/8
8/22 - 8/23
10/19 - 10/21
10/21 - 10/24
HURON
1
2
3
4
5
6
7
4/21 - 4/24 *
5/6 - 5/8
7/2 - 7/4 *
8/4 - 8/6
8/19 - 8/21
10/16 - 10/18
10/24 - 10/26
MICHIGAN
1
la
2
3
4
5
6
7
4/17 - 4/21
4/26 - 5/1 **
5/4 - 5/6
7/4 - 7/5 *
8/3 - 8/4
8/17 - 8/19
10/12 - 10/15
10/26 - 10/30
* No zooplankton sample
** No phytoplankton sample
-------
139
TABLE 2. Latitude and longitude of plankton sampling stations,
1983.
Station # Latitude Longitude
LAKE ERIE
LE60
41 53'
.30"
83 11
•48
LE57
41
49
54
83
01
06
LE55
41
44
18
82
44
00
LE42
41
57
54
82
02
30
LE73
41
58
40
81
45
25
LE37
42
06
36
81
34
30
LE78
42
07
00
81
15
00
LE79
42
15
00
80
48
00
LE18
42
25
18
80
04
48
LE15
42
31
00
79
53
36
LEO 9
42
32
18
79
37
00
LAKE
HURON
LH61
45
45
00
83
55
00
LH54
45
31
00
83
25
00
LH45
45
08
12
82
59
00
LH37
44
45
42
82
47
00
LH32
44
27
12
82
20
30
LH27
44
11
54
82
30
12
LH15
44
00
00
82
21
00
LH12
43
53
24
82
03
24
LH09
43
38
00
82
13
00
LH06
43
28
00
82
00
00
LAKE
MICHIGAN
LM06
42
00
00
87
00
00
LM10
42
23
00
87
25
00
LM18
42
44
00
87
00
00
LM22
43
08
00
87
25
00
LH27
43
36
00
86
55
00
LM32
44
08
24
87
14
00
LM41
44
44
12
86
43
18
LM46
45
13
24
86
36
48
LM64
45
57
00
85
35
12
LM77
45
47
24
84
49
24
-------
140
TABLE 3. Sample dates and stations for Lake Michigan, 1983.
Station
Number
Sample Dates
4/17-21 A/26-5/1 5/4-6 8/3-4 8/17-19 10/12-15 10/26-30
5
6
10
11
17
18
22
23
26
27
32
34
40
41
46
47
56
57
64
77
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-------
141
TABLE 4. Number of taxa and genera observed in each algal division or
grouping, 1983.
LAKE ERIE LAKE HURON LAKE MICHIGAN
Taxa Genera Taxa Genera Taxa Genera
Bacillariophyta
225
31
211
31
221
33
Chlorophyta
113
38
75
28
88
34
Chrysophyta
29
11
56
10
53
13
Cryptophyta
20
3
25
3
29
4
Cyanophyta
18
9
13
6
28
10
Colorless flagellates
15
6
13
4
16
6
Pyrrhophyta
10
4
10
4
10
4
Euglenophyta
2
2
4
3
1
1
Unidentified
3
-
3
-
5
-
Chloromonadophyta
1
1
1
1
1
1
TOTAL
436
105
411
90
452
106
-------
142
TABLE 5. Relative abundance of major phytoplankton divisions in Lakes Erie
Huron and Michigan. BAC=Bacillariophyta, CAT=Chloromanophyta
CHL=Chlorophyta, CHR=Chrysophyta, COL=Colorless Flagellates, CRY=Cryptophyta*
CYA=Cyanophyta, EUG=Euglenophyta, PYR=Pyrrhophyta, UNI=Unidentified. *
LAKE ERIE
Division
Biovolume/mL
%
Cells/mL
BAC
CAT
CHL
CHR
COL
CRY
CYA
EUG
PYR
UNI
59.93
0.01
14.91
0.88
0.10
9.13
4.14
0.04
8.40
2.47
1.38
0.01
1.95
0.61
0.07
1.73
89.58
0.01
0.03
4.65
LAKE HURON
Division
Biovolume/mL
Cells/mL
BAC 68.20 1.16
CAT 0.02 0.01
CHL 3.45 0.42
CHR 7.11 1.60
COL 0.14 0.06
CRY 8.29 1.13
CYA 4.31 89.53
EUG 0.11 0.01
PYR 3.25 0.01
UNI 5.11 6.09
LAKE MICHIGAN
% %
Division Biovolume/mL Cells/mL
BAC
56.41
1.07
CAT
0.02
0.01
CHL
5.25
0.65
CHR
6.53
1.49
COL
0.75
0.13
CRY
13.43
1.24
CYA
5.56
92.21
EUG
0.04
0.01
PYR
7.32
0.01
UNI
4.68
3.20
-------
143
TABLE 6. Summary of major phytoplankton species occurrence In Lake Erie during 1983. Summary
Is based on all samples analyzed. Summary Includes the maximum population density encountered,
the average population density and blovolume, and the relative abundance ($ of total cells and
% of total blovolume). Major species were arbitrarily defined as having an abundance of >0.1$
of the total cells or >0.5$ of the total blovolume.
Mean
Taxon
Maximum
Average
% of Total
Blovolume
f of Total
eel 1 s/mL
eel 1 s/mL
Cel 1 s
/mL
Blovolume
BACILLARIOPHYTA
Actlnocyclus normanll f. subsalsa
88
5.8
.01
36129
2.65
Fragllarla capuclna
603
49.8
.12
11645
.85
FragIIaria crotonensls
554
76.7
.19
47360
3.47
Meloslra granulate
555
25.2
.06
11522
.85
Rhlzosolenla sp.
507
7.2
.02
53354
3.91
Stephanod1scus alplnus
78
9.7
.02
14736
1.08
StephanodIscus blnderanus
234
17.9
.04
9836
.72
Stephanod1scus nlagarae
169
25.3
.06
507424
37.22
Tabellarla flocculosa
376
20.8
.05
51064
3.75
CHLOROPHYTA
Coelastrum mlcroporum
2291
135.5
.34
11054
.81
Cosmarlum sp.
49
3.0
.01
83415
6.12
Monoraphldlum contortum
744
82.0
.20
704
.05
Mougeotla sp.
352
13.4
.03
11991
.88
Oocyst Is borgel
155
15.3
.04
9465
.69
Pedlastrum simplex v. duodenarlum
376
11.5
.03
7172
.53
Scenedesmus ecornls
2193
111.7
.28
19837
1.46
Staurastrum paradoxus
16
.8
.01
14024
1.03
CHRYSOPHYTA
Haptophyte sp.
785
158.6
.40
1781
.13
CRYPTOPHYTA
Chroomonas norstedt11
515
53.4
.13
1289
.09
Cryptomonas erosa
286
30.4
.08
66163
4.85
Rhodomonas mlnuta v. nannoplanktlea
1890
564.8
1.41
32813
2.41
CYANOPHYTA
Agmenellum quadruplIcatum
3305
70.1
.18
19
.01
Anacystls marina
141208
33171.1
82.81
8893
.65
Anacystis montane v. minor
5072
219.1
.55
1650
.12
Aphanlzomenon flos-aquae
2561
91.5
.23
684 4
.50
Coccochlorls penlocystls
7175
697.3
1.74
1826
.13
Coelosphaerlum naegel1anum
5891
235.9
.59
2785
.20
MerIsmopedia tenulsslma
15544
333.2
.83
104
.01
Oscillator la llmnetlce
11266
460.1
1.15
3295
.24
Oscillator la subbrevls
27399
404.4
1.01
15796
1.16
Osc111ator1 a t«nu[s
5081
79.5
.20
4466
.33
PYRRHOPHYTA
Ceratlum hlrundlnella
16
1.4
.01
66724
4.89
Gymnodlnlum sp. #2
16
.7
.01
6932
.51
Per Id Inlum aclcullferum
16
1.0
.01
10300
.76
Per Id Inlum sp.
106
3.8
.01
19741
1.45
UNIDEMTIFIED
Unidentified flagellate - ovoid
3960
1296.0
3.24
24405
1.79
Unidentified flagellate - spherical
1301
564.3
1.41
9238
.66
TOTAL
97.51
TOTAL
86.98
-------
144
TABLE 7. Summary of major phytopIank+on species occurrence In Lake Huron during 1983. Summary Is
based on all samples analyzed. Summary Includes the maximum population density encountered, the
average population density and blovolume, and the relative abundance (? of total cells and % of total
blovolume). Major species were arbitrarily defined as having an abundance of >0.1J{ of the
total cells or >0.5f of the total blovolume.
Mean
Taxon
Maximum
Average
f of Total
Blovolume
eel 1s/mL
eelIs/mL
Cel 1 s
Jim /mL
BACILLARIOPHYTA
Asterlonella formosa
103
9.7
.04
2957
Cyc1ote11 a comens1s
385
49.2
.29
1698
Cyclotella comta
51
6.4
.03
17659
Cyclotella kue+zlnglano v. planetophore
80
16.5
.07
4975
Cyclotel1 a ocel1ata
254
29.9
.13
2330
Cymatopleura soles v. ap leu lata
3
.2
.01
13446
Frag IIor la crotonensls
123
27.6
.12
22889
Fragllarla Intermedia v. fallax
60
8.2
.04
5019
Meloslra Islandlca
90
12.7
.06
16985
Rhlzosolenla sp.
143
17.2
.08
127442
Stephanodlscus nlagarae
3
.3
.01
5755
StephanodIscus transl1 vanleus
8
.9
.01
8838
Tabellarla flocculosa
133
20.3
.09
60602
Tabellarla flocculosa v. linearis
21
1.4
.01
2554
CHRYS0PHYTA
Chrysosphaerella longlspina
74
13.5
.06
5276
D1nobryon cy1Indr1cum
164
16.1
.07
5850
Dlnobryon dlvergens
141
21.6
.10
4704
Dlnobryon soclale v. amerlcanum
524
49.1
.22
5997
Haptophyte sp.
859
168.0
.75
1571
CRYPT0PHYTA
Cryptomonas erosa
16
5.4
.02
10213
Cryptomonas erosa v. reflexa
8
1.3
.01
2472
Cryptomonas pyrenoldlfera
33
6.1
.03
3497
Rhodomonas mlnuta v. nannoplanktlca
311
204.4
.92
15173
CYAN0PHYTA
Anacystls marina
55518
18010.5
80.63
8456
Anacystls montana v. minor
2556
379.9
1.70
1667
Anacystls thermal 1s
115
17.3
.08
2425
Coccoch|or 1s e1abans
434
37.7
.17
421
Coccochlorls penlocystls
7929
1332.4
5.96
3336
Coelosphaerturn naegellanum
900
73.7
.33
332
Gomphosphaerla lacustrls
920
37.6
.17
204
Oscillator la llmnetlca
974
87.2
.39
281
PYRfUlOPIIYTA
Ceratlum hlrundlnella
2
.1
.01
5590
Gymnodlnium sp.
8
.3
.01
2735
Gymnodlnlum sp. #2
2
.2
.01
3374
UNIDENTIFED
Unidentified flagellate - ovoid
1135
489.3
2.19
10434
Unidentified flagellate - spherical
5211
870.5
3.90
12335
TOTAL
98.72
TOTAL
B lovo I ume
.66
.9
3.94
1.11
.52
3
5.11
1.12
3.79
28.44
1.28
1.97
13.52
.57
1.16
1.31
1.05
1.34
.35
2.28
.55
.78
3.39
1.89
.37
.54
.09
.74
.07
.05
.06
1.25
.61
.75
2.33
2.75
89.66
-------
145
TABLE 8. Summary of major phytopInnkton species occurrence In Lake Michigan during 1983.
Summary Is based on all samples analyzed. Summary Includes the maximum population density
encountered, the average population density and blovolume, and the relative abundance 1% of
total cells and f of total blovolume). Major species were arbitrarily defined as having an
abundance of >0.1$ of the total cells or >0.5? of the total blovolume.
Mean
Taxon
Maximum
Average
% of Total
B lovolume
% of Total
eel 1 s/mL
eel Is/mL
Cel Is
Mm /mL
Blovolume
BACILLARIOPHYTA
Asterlonella formosa
206
11.8
.04
3541
.91
Cyclotella comensls
834
52.7
.24
1958
.97
Cyclotella comta
158
6.3
.02
15647
4.01
Cyclotella mlchlganlana
117
12.1
.04
2664
.68
Cymatopleura solea
5
.3
.01
5991
1.54
Entomonels ornata
4
.2
.01
3346
.86
FragIIaria crotonensls
755
59.4
.21
42373
10.86
FragIIaria vaucherlae
115
10.0
.04
4572
1.17
Meloslra Islandlca
137
12.1
.04
10920
2.80
Meloslra Itallea subsp. subarctlca
357
36.6
.13
6667
1.71
Rhlzosolenla erlensls
53
2.6
.01
6165
1.58
Rhlzosolenla sp.
133
1.7
.01
7204
1.85
Stephanod1scus alplnus
22
3.0
.01
19375
4.96
Stephanodlscus nlagarae
18
.8
.01
9876
2.53
Stephanod1scus trans 1 IvanIcus
6
.3
.01
6326
1.62
Tabellarla fenestrate
79
4.1
.01
7247
1.86
Tabellarla flocculosa
202
16.8
.06
48991
12.55
CHL0R0PHYTA
1.79
Cosmarlum sp.
8
.4
.01
6985
Green coccold - bact11Iform
376
39.5
.14
832
.21
Honoraphldlum contorturn
201
38.1
.14
310
.08
S+lchococcus sp.
761
23.0
.08
1969
.50
CHRYSOPHYTA
Dlnobryon cyllndrlcum
311
17.8
.06
5732
1.47
OInobryon dlvergens
258
15.5
.06
2317
.59
Dlnobryon soclale v. amerlcanum
802
47.7
.17
6227
1.60
Haptophyte sp.
785
185.0
.66
2306
.59
Unidentified coccolds
540
46.5
.17
478
.12
Stylotheca aurea
172
6.7
.02
2142
.55
CRYPTOPHYTA
.17
Chroomonas norstedt11
202
28.8
.10
653
Cryptomonas erosa
25
6.7
.02
14345
3.68
Cryptomonas erosa v. reflexa
11
1.2
.01
2464
.63
Cryptomonas marsson11
25
2.5
.01
2249
.58
Cryptomonas pyrenoldlfera
49
6.1
.02
2783
.71
Rhodomonas ml nuta v. nannoplanktlca
777
268.8
.96
22375
5.73
CYANOPHYTA
1.62
Anacystls marina
120019
23607.8
84.61
6329
Anacystls montana v. minor
3289
451.2
1.62
2994
.77
Coccochlorls penlocystls
11437
1339.7
4.80
3014
.77
Coelosphoerlum naegellanum
1227
39.3
.14
165
.04
Gomphosphaerla lacustrls
818
37.9
.14
265
.07
Oscl1latorla agardhl1
344
14.2
.05
2791
.72
Oscillator la llmnetlca
2266
139.3
.50
1033
.26
PYRRHOPHYTA
Caratlum hlrundlnella
8
.2
.01
20898
5.36
Gymnodlnlum sp. #2
16
.3
.01
3765
.96
Per Id Inlum sp.
8
.4
.01
2584
.66
UNIDENTIFIED
Unidentified flagellate - ovoid
1630
393.4
1.41
9707
2.49
Unidentified flagellate - spherical
1859
499.2
1.79
8415
2.16
TOTAL
98.62
TOTAL
87.34
-------
TABLE 9. Relative abundance of taxa and number of taxa and genera observed In each zooplankton grouping, 1983,
LAKE ERIE
LAKE HURON
LAKE MICHIGAN
Taxa
Genera
% of Total
Abundance
Taxa
Genera
% of Total
Abundance
Taxa
Genera
J of Tot
Abundano
Rot Ifera
34
IB
69.2
31
17
41.1
33
20
59.7
Cladocera
19
13
6
15
B
4.e
23
13
3.2
Calanoldo
10
5
3.7
9
4
19.8
10
5
10.1
Cyclopoldo
7
4
5.4
5
3
11.2
5
4
5.7
Harp actIcoldo
t
-
<0.1
0
0
0
1
-
<0.1
Mysldacea
0
0
0
1
1
<0.1
1
1
<0.1
Copepoda naupl11
-
-
15.B
-
-
23.1
-
-
21.3
Total
71
41
61
33
73
43
A
0\
-------
147
TABLE 10. Mean abundances of zooplankton groups during the study period.
Lake Erie
Lake Huron
Lake Michigan
Rotifera
195,966
17,035
41,331
Cladocera
16,224
2,448
2,143
Copepoda Nauplii
41,515
5,924
11,893
Cyclopoida
12,759
5,072
3,924
Calanoida
9,115
10,677
6,138
Mysidacea
0
0
0.33
Harpacticoida
4.2
0
0.10
Mean
288,341
(195,344)
46,230
(44,502)
69,353
(35,087)
-------
148
TABLE 11 Sunwary of common zooplankton species occurrence In lake Erie during 1983. Values are from
the short zooplankton hauls. Summary Includes the maximum population density encountered, the average
density and the relative abundance. Parentheses Indicate values from the long haul.
Taxon
Max I mum
Organ Isms/m3
x 1000
Average
DensIty
f/m*
% of Total
Organ Isms"
ROTIFERA
Polyarthra vulgaris
Synchaeta sp,
Kerate11 a cochI ear Is
Conochllus unicornis
Kerate11 a hIema11s
Brachlonus sp.
Polyarthra do)Ichoptera
Polyarthra major
Ascomorpha ecaudls
Notholca laurentlae
Col Ietheca sp.
Kerate11 a crassa
Notholca follacea
KelI icottla long I spina
CLADOCERA
Eubosmlna coregon1
Paphnla galaeta mendotae
Daphnla retrocurva
Bosmlna longlrostrls
Olaphanosoma leuchtenberglanum
Chydorus sphaerlcus
COPEPODA
Copepoda naupl11
Cyclopolda
Cyclopold copepodlte
Cyclops blcusbldatus thomasl
Mesocyclops edax
Tropocyclops prastnus mexlcanus
Calanolda
Ca/anofd copepodlte
Dlaptomus oregonensls
Olaptomus slclloldes
334.0
370.0
111.0
112.0
127.0
540.0
155.0
24.0 (26)
64.0
83.0
59.0
97.0
59.0
37.0
64.0
60.0
70,0
8.0
9.0
14.0
TOTAL
133.0
22.0 (25)
12.0
15.0
3.3 (6.0)
40.0
12.0
13.0
94.4
49739
29442
19647
14006
10701
9307
8329
6395 ( 8558)
6446
6964
5298
5384
5402
3590
4505
4055
4183
1628
966
476
41515
7512 (10895)
28 25
1669
748 (1782)
6120
2034
600
18.44
9.54
7.27
5.34
3.53
2.98
2.70
2.62
2.33
2.27
2.03
1.82
1.75
1.29
1.66
1.54
1.42
.65
.38
.16
15.76
3.13
1.23
.67
.36
.54
.82
.19
Species were arbitrarily classified as common If they accounted for >0.1$ of the total
abundance for the study period except for the Rotlfera. Rotifer species were considered
common If they accounted for >1.0$ of the total abundance.
2. Short and long hauls are grouped together.
-------
149
TABLE 12 Summary of common zooplankton species In Lake Huron during 1983. Summary
Includes the maximum population density encountered, the average density and the
relative abundance. Values are from the short zooplankton hauls. Parentheses Indicate
values from the long haul.
Average Percent
Maximum Density of Total
Taxon Organlsms/m1 Numoer/m1 Organisms1
ROTIFERA
Conochllus unicornis
19,750
7,050
11.2
Kelllcottla longlspina
7,106 (21,721 )
2,068 (176)
8.6
Keratella cochlear Is
5,457 (18,633)
2,040 (356)
7.2
Polyarthra vulgaris
8,249
2,955
5.3
Gastropus sty lifer
4,244 (6,815)
1,132 (81)
2.6
Synchaete sp.
1,277
175
1.7
Col letheca sp.
2,196
848
1.5
ADOCERA
Daphnla galaeta mendotae
4,076
1,029 (16)
1.4
Bosmlna longlrostrls
1,598 (2,813)
518 (409)
1.2
Daphnla pulIcarla
2,791
363
.7
Daphnia retrocurva
2,148 (2,423)
74 (82)
.6
Eubosmlna coregonl
998
229
.4
Daphnla schodlerl
1,630
164
.2
Daphnla catawba
0 (1,610)
0 (70)
.2
Hoi opedlum glbberum
406 (468)
58
.1
PEPOOA
Copepoda naupl11
11,766 ( 38,290)
5,924 (962)
23.1
Cyclopolda
Cyclopold copepodlte
8,608
4,3W
9.8
Cyclops blcuspldatus thomasl
2,346
452
1.1
Tropocyclops praslnus mexlcanus
577
109
.2
Mesocyclops edax
930
115
.1
Calanolda
Calanold copepodlte
19,707
9,666
17.6
Dlaptomus mlnutus
2,063
465
.8
Dlaptomus ash 1 and 1
802 (1,008)
206 (332)
.6
Dlaptomus slcl1 Is
1,141
145
.4
Dlaptomus oregonensls
413
140
.3
TOTAL 97.0
1. Species were arbitrarily classified as common If they accounted for >0.1| of the
total abundance for the study period with the exception of the Rot Ifera. Rotifer
species were considered common If they accounted for >1.0$ t of the total abundance.
2. Short and long hauls are grouped together.
-------
150
TABLE 13 Summary of common zooplankton species occurrence In Lake Michigan during 1983.'
Values are from the short zooplankton hauls. Summary Includes the maximum population
density encountered, the average density and the relative abundance. Parentheses Indicate
values from the long haul.
Maximum
Average
Percent
ROTIFERA
CLADOCERA
Organlsms/mJ
DensIty
of Total
Taxon
x 1000
Number/m1
Organ 1sms
Polyarthra vulgaris
109
16992
20.8
Synchaeta sp.
84
8593
11.6
Kera+ella cochlear Is
58
3463
7.2
Polyarthra major
23
1928
3.1
Kelllcottla longlsplna
10
(15)
981
(4,688)
2.6
Conochllus unicornis
21
1772
2.5
Polyarthra dollchoptera
33
1368
2.1
Keratella crassa
12
(23)
982
(63)
1.9
Gastropus sty lifer
12
(31 )
917
(972)
1.7
Col 1etheca sp.
6.0
(6.5)
1083
(391)
1.6
Keratella earlInae
19
837
1.0
Notholca squamula
11
594
1.0
k
Bosmlna longlrostrls
17
923
1.4
Oaphnla galaeta mendota
3.5
445
.6
Daphn1 a pu1Icar1 a
6.1
376
.7
Daphnta retrocurva
3.2
115
.2
Eubosmlno coregonl
1.2
95
.1
Hoi oped lum gibber-urn
2.1
86
.1
COPEPODA
Copepoda naupl11
Cyclopolda
Cyclopold copepodlte
Cyclops bicuspldatus thomasl
Tropocyclops praslnus mexlcanus
Calanolda
Calanold copepodlte
Dlaptomus ash I and I
Dlaptomus sic 11 Is
Dlaptomus mlnutus
Dlaptomus oregonensls
Llmnocalanus macrurus
39 11893 21.3
27 2516 3.7
5.2 1140 1.6
3.6 238 .3
14 (43 ) 4589 (5,099 ) 7.7
6.5 699 1.1
4.2 386 .6
.8 167 .2
1.0 (1.1) 115 (88) .2
1.7 138 .2
TOTAL 97.7
Species were arbitrarily classified as common If they accounted for >0.1f of the total
abundance for the study period with the exception of the Rot Ifera. Rotifer species were
considered common If they accounted for >1.0< of the total abundance.
2. Short and long hauls are grouped together.
-------
151
TABLE 14. Zooplankton species having major differences in abundances
between the long and short hauls. Lake Erie.
short long
Taxon tfTm5 T~ IIP %
Rotifera
Synchaeta sp. 29442 10.68 1447 0.82
Keratella hiemalis 10701 3.88 1514 0.86
Polyarthra dolichoptera 8329 3.02 488 0.04
Notholca laurentiae 6964 2.52 616 0.35
Polyarthra major 6394 2.32 8558 4.87
Notholca foliacea 5402 1.96 300 0.17
Keratella crassa 5384 1.95 1426 0.81
Notholca squamula 1916 0.69 71 0.04
Keratella earlinae 1672 0.61 229 0.12
Cladocera
Daphnia retrocurva 4183 1.52 1239 0.70
Chydorus sphaericus 476 0.17 64 0.04
Cyclopoida
Cyclops bicuspidatus thomasi 2825 1.02 4857 2.76
Mesocyclops edax 1669 <0.01 2011 1.11
-------
152
TABLE 15. Zooplankton species having major differences in abundances
between the long and short hauls. Lake Huron.
Tax on
short
%
#/m3
long
%
Rotifera
Conochilus unicornis
Polyarthra vulgaris
Keratella cochlearis
Synchaeta sp.
Keratella earlinae
Keratella quadrate
Notholca laurentiae
Cladocera
Daphnia galaeta mendotae
Daphnia retrocurva
Daphnia schodleri
Eubosmina coregoni
7050
2955
2040
174
82
74
27
1029
74
164
229
17.13
7.18
4.96
0.42
0.20
0.18
0.07
2.51
0.18
0.40
0.56
2492
1506
3637
1105
168
609
330
181
388
20
97
6.17
3.75
9.01
2.70
0.41
1.50
0.80
0.45
0.96
<0.01
0.24
Copepoda
Copepoda nauplii 5924 14.39
Cyclopoida
Mesocyclops edax 115 0.28
Tropocyclops prasinus mexicanus 109 0.26
Calanoida
Calanoid copepodite 9666 23.50
Diaptomus minutue 465 1.13
12319
55
52
5100
190
30.50
0.14
0.13
12.60
0.47
-------
153
TABLE 16. Zooplankton species observed in either the long or short hauls,
Lake Huron.
Mean
#/m3
% of Total
Abundance
Type of Haul
Cladocera
Daphnia catawba
Daphnia dubia
Diaphanosoma leuchtenbergianum
Cyclopoida
Cyclops vernalis
Mysidacea
Mysis relicta
Rotifera
70.0
1.9
0.36
0.49
0.26
.37
.005
<.001
.001
< .001
long
short
short
short
long
Notholca squamula
72.0
.41
long
Notholca foliacea
29.0
.073
long
Polyarthra remata
10.0
.027
short
Keratella hiemalis
10.0
.025
long
Keratella cochlearis hispida
2.9
.007
short
Cephalodella sp.
3.1
.007
short
Monostyla lunaris
1.7
.004
short
Euclanis sp.
0.42
.001
long
-------
154
TABLE 17. Zooplankton species having major differences in abundances
between the long and short hauls, Lake Michigan.
Tax on
short
#/m3
#/m3
long
Rotifera
Polyarthra vulgaris
Kellicottia longispina
Keratella earlinae
Keratella quadrata
16992
980
836
144
25.97
6.50
1.27
0.22
2662
1756
141
391
7.96
5.25
0.42
1.17
Copepoda
Copepoda nauplii
11893
18.17
9662
28.91
-------
155
TABLE 18. Zooplankton species observed in either the long or short hauls.
Lake Michigan.
Mean % of Total
#/m3 Abundance Type of Haul
Rotifera
Lecane tunuiseta
2.7
.008
long
Notholca striata
1.0
.003
long
Encentrum sp.
0.85
.003
long
Notholca acuminata
0.38
.001
long
Euclanis sp.
0.28
<.001
long
Brachionus quadridentatus
0.19
<.001
long
Monostyla sp.
0.13
<.001
short
idocera
Ceriodaphnia lacustris
0.79
.001
short
Daphnia longiremis
0.78
.001
short
Daphnia middendorffiana
0.04
<.001
short
Camptocercus rectirostris
0.04
<.001
long
Diaphanosoma leuchtenbergianum
0.27
<.001
short
Cyclopoida
Eucyclops prionophorus 0.01 <.001 short
-------
15©
TABLE 19. Comparison of average abundance and biomass of plankton
in Lakes Erie, Huron and Michigan, ApriI-October, 1983
Algal
Abundance
(eel 1s/ml)
Algal
B iomass
(g/m3)
ZoopIankton
Abundance
<#/m3)
Ca1anoId
Cyc.tCIad.
Lake Erie
40,055
1.36
288,341
0.33
Lake Huron
19,147
0.38
46,230
1.43
Lake Michigan
29,839
0.42
69,353
1.02
-------
TABLE 20. Mean maximum abundance of selected common phytoplankton species in
1970 and 1983* Lake Erie. Data from Munawar and Munawar (1976) and this study.
1970 data - graphical accuracy.
Actinocyclus normanii
Stephanodiscus
niagarae
Stephanodiscus
tenuis
Stephanodiscus
binderanus
Fragilaria
crotonensis
Fragilaria
capucina
Peridinium
aciculiferum
Ceratium
hirundinella
Rhodomonas
minuta
Cryptomonas
erosa
Pediastrum
simplex
Staurastrum
paradoxum
Aphan i zomenon
flos-aquae
Oscillatoria
subbrevis
1970 1983
BASIN g/m g/m
Western 4.7 0.30
Eastern 1.4 1.05
Central 2.3 1.90
Western 0.6 0.12
Western 1.8 0.001
Western 0.5 0.11
Eastern 1.0 0.15
Central 3.4 0.11
Western 7.9 0.18
Central 2.4 0.03
Eastern 0.4 0.006
Central 0.2 0.06
Eastern 1.0 0.05
Central 1.8 0.35
Eastern 2.0 0.31
Eastern 1.6 0.04
Central 0.4 0.10
Western 2.0 0.63
Central 0»4 0.06
Central 0.4 0.07
Western 2.0 0.10
Western * 0.35
* Hot listed as a common or
uncommon species
by Munawar
and Munawar (1976)
-------
158
TABLE 21. Total mean phytoplankton biomass for the western, central and
eastern basins, 1983, Lake Erie.
Western Central Eastern
Basin Basin Basin
3
Biomass (g/m ) 1.49 1.59 0.84
-------
159
TABLE 22. Comparison of phytoplankton biomass values between 1956 and 1983 in
western Lake Erie. Modified from Gladish and Munawar (1980).
AUTHOR(S)
Davis (1958)
Verduin (1964)
Munawar & Munawar
(unpublished)
Munawar & Munawar
(unpublished)
Gladish & Munawar (1980)
This study
TIME AND LOCATION OF STUDY
1956, Bass Island region
June 1957 to August 1958
Bass Islands region
April to December 1970
Off tip of Pt. Felee
April to December 1970
Near Detroit River mouth
June 1975 to September 1976
Northern waters
April to October 1983
BIOMASS
g/m
6.1
4.1
3.8
4.9
2.5
1.5
-------
160
TABLE 23. Comparison of abundance of selected species at offshore sites in
August of 1970 and 1983. Data from Holland and Beeton (1972) and this study.
11 August 1970 17 August 1983
(Offshore Stations) (Stations 22 & 27)
cells/mL cells/mL
Cyclotella michiganiana 92,182,71 0.44,6.8
Cyclotella stelligera 300,467,613 0.17,2.2
-------
161
TABLE 24. Phytoplankton abundance in 1962, 1977 and 1983 in southern Lake
Michigan. Data from Stoermer and Kopczynska (1967a and b), Rockwell et al.
(1980) and this study.
Year
Site
Abundance
cells/mL
Sampling Dates
1962-63
Offshore
Nearshore
125-1,170
? -2,770
April,May,June,July
August,September
1976-77
Offshore (?)
1,190-6,000
April,June,August,
September
1983
Offshore
14,944-48,305
(with picoplankton)
Ap ril,May,July,August
(Mean of all
Stations)
1,895-4,276 late August,mid-October,
(without picoplankton) late October
1983
Offshore
(Station 6)
1,244-6,398 late August,mid-October,
(without picoplankton) late October
-------
162
TABLE 25. Species having peak abundances in the western, central or eastern
basin of Lake Erie, 1983.
WESTERN BASIN
Bosmina longirostris
Eubosmina coregoni
Diaphanosoma leuchtenbergianum
Brachionus caudatus
Brachionus sp.
Filinia longiseta
Keratella cochlearis
Keratella earlinae
Notholca foliaceae
Notholca laurentiae
Synchaeta sp.
Trichocerca cylindrica
Trichocerca multicrinis
CENTRAL BASIN
Diaptomus oregonensis
Cyclops bicuspidatus thomasi
Daphnia galeata mendotae
Colletheca sp.
Kellicottia longispina
Keratella hiemalis
EASTERN BASIN
Daphnia galeata mendotae
Mesocyclops edax
Tropocyclops prasinus mexicanus
-------
163
TABLE 26. Ratio of calanoids to cladocerans plus cyclopoide in Lake Erie.
1983.
WESTERN CENTRAL EASTERN MEAN
BASIN BASIN BASIN
Calanoid 0.19 0.31 0.45 0.32
Cladocer&n + Cyclopoid
-------
164
TABLE 27. Comparison of mean crustacean abundance for the sampling period
in 1971 (April-November). 1974/75 (April-November) and 1983 (August-
October). 1971 data modified from Watson and Carpenter (1974), 1974/75
data from McNaught et al. (1980). NF = not found. Values are number/
SPECIES
1971
1974/75**
1983
Cladocera
Bosmina longirostris
553
(1047)*
4109
518
Eubosmina coregoni
330
(765)*
2084
229
Daphnia retrocurva
361
74
Daphnia galeata mendotae
339
(852)*
692
1029
Daphnia longiremis
Daphnia pulicaria
0
(0)
0
363
Chydorus sphaericus
18
(580)*
391
NF
Holopedium gibberum
229
576
58
Cyclopoida
Cyclops bicuspidatus
3764
(3274)*
1271
2346
thomasi
Cyclops vernalis
7.5
(5)*
117
.5
Tropocyclops prasinus
63
(61)*
310
577
mexicanus
Mesocyclops edax
5
(6.7)*
91
115
Calanoida
Diaptomus ashlandi
246
(37)*
745
206
Diaptomus minutus
462
(322)*
966
465
Diaptomus sicilis
117
(77)*
496
145
Diaptomus oregonensis
109
(92)*
192
140
Limnocalanus macrurus
64
(44)*
34
9.3
* August, September and October average
** Includes Saginaw Bay
-------
165
TABLE 28. Ratio of Calanoida to Cladocera plus Cyclopoida in Lake Huron,
1983.
Calanoida
Station
Cyclopoida +
61
(North)
0.67
54
1.11
45
1.19
37
1.57
32
2.13
27
1.37
15
1.60
12
1.98
09
1.31
06
(South)
1.23
-------
166
TABLE 29 Mean abundance of rotifers in Lake Huron in 1974 and 1983.
Data from 'stemberger et al. (1979) and this study. NF = not found in short
tow.
1974
1983
April-Nov.
#/L
Aug.-Oct.
#/L
Colletheca sp.
0.8
0.90
Conochilus unicornis
15.0
7.10
Filinia longiseta
3.4
0.004
Gastropus stylifer
5.2
1.10
Kellicottia longispina
6.8
2.10
Keratella cochlearis
41.9
2.00
Keratella earlinae
10.9
0.08
Notholca squamula
7.4
NF
Polyarthra dolichoptera
3.0
0.07
Polyarthra remata
6.8
0.01
Polyarthra vulgaris
17.6
3.00
Synchaeta kitina
8.1
NF
Synchaeta stylata
7.1
NF
Synchaeta sp.
2.4
0.10
-------
TABLE 30. Cladoceran abundance in
1954. 1966, 1968
and 1983
in
Lake Michigan. Data from Wells (1970) and this study. Dashes
indicate that no collections
were
made. Values are
number /m3
•
Earl?
' Late June-
Mid-
Early
Species and Year
June
Early July
July
August
Leptodora kindtii
1954
0
12.0
13.0
29.0
1966
0
0.2
2.9
3.5
1968
-
-
9.8
16.0
1983
-
-
-
33.5
Daphnia galeata
1954
2.3
160.0
580.0
1200.0
1966
0
0.1
0
0
1968
-
-
2.5
0.4
1983
-
-
-
514.0
Daphnia retrocurva
1954
0
270.0
1400.0
1400.0
1966
0
2.4
17.0
79.0
1968
-
-
1200.0
2100.0
1983
-
-
-
82.0
Diaphanasoma brachyurum
1954
0.1
4.5
4.3
1.6
1966
0
0
0
0
1968
-
-
0
0
1983
-
-
-
0.9
Daphnia longireois
1954
0
0
0
0
1966
6.1
5.7
1.2
16.0
1968
-
-
0.1
0
1983
-
-
-
0
Daphnia pulicaria
1954
-
-
-
-
1966
-
-
-
-
1968
-
-
-
-
1983
-
-
-
1011
Holopedium gibberum
1954
0
0
0
0
1966
0
0.5
2.1
2.3
1968
-
-
5.8
4.6
1983
-
-
-
456.0
Polyphemus pediculus
1954
0
0.5
0.6
2.0
1966
0
4.4
82.0
15.0
1968
-
-
170.0
9.7
1983
-
-
-
12.6
Bosmina longirostris
1954
7.1
250.0
40.0
26.0
1966
30.0
320.0
240.0
98.0
1968
-
-
130.0
16.0
1983
-
-
-
342.0
Eubosmina coregoni
1954
0
0
0
0
1966
0
0.1
0.3
0.6
1968
-
-
72.0
16.0
1983
-
-
-
159.0
Ceriodaphnia quadrangula
1954
0
0
0
0
1966
0
0
3.4
3.7
1968
-
-
0.3
0.5
1983
-
-
-
0
-------
TABLE 31.Copepod abundance in 1954. 1966, 1968, and 1983 in Lake
Michigan. Data from Wells (1970) and this study. Dashes indicate
that no collections were made. Values are number/m •*.
Early
Late June-
Mid-
Early
Species and Year
June
Early July
July
August
Limnocalanus macrurus
1954
460.0
160.0
71.0
91.0
1966
15.0
22.0
5.6
34.0
1968
-
-
89.0
270.0
1983
-
-
-
18.0
Gpischura lacustris
1954
3.7
20.0
140.0
41.0
1966
0
17.0
3.2
6.6
1968
-
-
84.0
21.0
1983
-
-
-
18.5
Diaptomus eicilis
1954
190.0
72.0
12.0
3.0
1966
0
3.0
2.0
1.0
1968
-
-
2.0
3.0
1983
-
-
-
79.0
Mesocyclops edax
1954
0
260.0
460.0
200.0
1966
0
0
0
0
1968
-
-
1.0
0
1983
-
-
-
12.5
Senecella calanoides
1954
0
0.6
0.4
0.2
1966
0
0.2
0
0.2
1968
-
-
0.2
0.1
1983
-
-
-
1.4
Cyclops bicuspidatus
1954
1100.0
630.0
770.0
310.0
1966
1700.0
1300.0
1900.0
1000.0
1968
-
-
1200.0
860.0
1983
-
-
-
1457.0
Diaptomus ashlandi
1954
25.0
160.0
200.0
140.0
1966
320.0
280.0
150.0
220.0
1968
-
-
67.0
13.0
1983
-
-
-
1256.0
Cyclops vernalis
1954
0
0
0
0
1966
1.0
8.0
0
0
1968
-
-
1.0
0
1983
-
-
-
0
Eurytemora affinis
1954
0
0
0
0
1966
0
4.0
6.0
33.0
1968
-
-
55.0
3.0
1983
-
-
-
0
Diaptomus oregonensis
1954
10.0
17.0
73.0
63.0
1966
38.0
10.0
110.0
58.0
1968
-
-
15.0
100.0
1983
-
-
-
138.0
Diaptomus minutus
(
1954
82.0
220.0
110.0
39.0
1966
320.0
400.0
88.0
25.0
1968
-
-
660.0
1500.0
1983
-
-
-
151.0
-------
169
TABLE 32. The ratio of calanoids to cyclopoids plus cladocerans
geographically in Lake Michigan, 1983.
Calanoida
Station
Cyclopoida +
77
(North)
0.37
64
0.41
57
1.74
47
1.52
41
1.10
34
1.03
27
1.53
23
1.15
18
3.01
11
1.71
6
(South)
0.87
-------
Lake Erie
Main Lake Sampling Station
Lake Ontario
Lake
Huron
Canada
Michigan
15
18
Lake
St. Clair
Detroit
79
37 78
Erie New York
42 73
60
55
Pennsylvania
Toledo
Cleveland
United States
Ohio
FIGURE I
Lake Erie plankton sampling stations, 1983
M
O
-------
M
#57
54
53
48
45
43
38
37
32
29
27
93
Lake Huron
Main Lake
Sampling Locations
~ 10/24 - 10/26 ONLY
92
90
FIGURE 2
Lake Huron plankton sampling stations, 1983
-------
Station Locations
Lake Michigan - Main Lake
Manistique
N
Manitowoc
V
Milwaukee
<
Racine
Waukegon
Chicago
Green
Ludmgton
26 27
22 23
17 18
10 11
Petosky
Traverse City
Michigan
Muskegon
5 6
Benton Harbor
FIGURE 3
Lake Michigan plankton sampling stations, 1983
-------
173
50 -
O
g 40
30 -
E
^ 20
a>
o |0
4a.
LAKE ERIE
LAKE MICHIGAN
LAKE HURON
r-
- 4b.
E
I
6
E
A M J
1983
J l
FIGURE 4
Seasonal phytopIankton abundance (4a) and blovolume
(4b) trends fn Lakes Erie, Huron and Michigan
-------
174
<
J—
o LlJ
H 2
^ 3
° o
ZO
y cd
cc
LU
CL
LAKE ERIE
FIGURE 5
Seasonal distribution of algal divisions In Lake
Erie. BAC = Bacl11arlophyta, CHL = Chlorophyta,
CHR = Chrysophyta, CRY = Cryptophyta, CYA *
Cyanophyta, PYR = Pyrrhophyta.
-------
175
LAKE HURON
A M
FIGURE 6 Seasonal distribution of algal divisions In Lake
Huron. BAC ¦ Bad I larlophyta, CHL ¦ Chlorophyta,
CHR ¦ Chrysophyta, CRY ¦ Cryptophyta, CYA ®
Cyanophyta, PYR ¦ Pyrrhophyta.
-------
176
.8
LAKE MICHIGAN
.7
.6
.5
.4
.3
.2
.1
BAC
*¦--* CHL
CHR
• CRY
CYA
PYR
N
FIGURE 7 Seasonal distribution of algal divisions In Lake
Michigan. BAC = Bacl I larlophyta, CHL = Ch IoroDhvt*
CHR = Chrysophyta, CRY = Cryptophyta, CYA *
Cyanophyta, PYR = Pyrrhophyta.
-------
177
LAKE ERIE
1.0
0.5
3
2
I
CHRi
CRY<
60
40
20
WEST
BAC
CHL
CYA
TOTAL
EAST
r
i i 1 1 1 1 1 1 1 r
60 57 55 42 73 37 78 79 18 15 9
STATION
FIGURE 8 Annual geographfcal distribution of major divisions
fn Lake Erla. BAC ¦ Bacll larlophyta, CHL «
Chlorophyta, CHR ¦ Chrysophy+a, CRY - Cryptophyta,
CYA ¦ Cyanophyta, PYR ¦ Pyrrhophyta.
-------
178
LAKE ERIE
June 27 - July I <
Oct. 21-24
O
O
O
80 -
60 "
w 40
UJ
L>
20 -
WEST
EAST
i—i—i—i—i—i—I—i—i—T
60 57 55 42 73 37 78 79 18 15
STATION
FIGURE 9
Geographical distribution of phytop lankton abundance
on the June and October cruises. Lake Erie.
-------
179
.4 -
3
.2 -
.1 -
LAKE HURON
O
O
O
.3 "
2
w J
_i
Ui
o
30 -
20
10
TOTAL
NORTH
SOUTH
6'l 5*4 45 37 32 27 J5 12 5 6~~
STATION
FIGURE 10 Annual geographical distribution of major algal
divisions In Lake Huron. BAC « BacIIlartophyta,
CHL ¦ Chlorophyta, CHR ¦ Chrysophyta, CRY ¦
Cryptophyta, CYA » Cyanophyta, PYR ¦ Pyrrtiophyta.
-------
180
LAKE HURON
NORTH
SOUTH
80
60
40 -
20 -
Aug. 19-21
Oct. 16-18
J 1 1 I 1 I I
I
J L
60 -
40 -
20 -
April 21-24
May 6-8
Aug- 4-6
~1 f 1 1 1 1 T
61 54 45 37 32 27 15
STATION
FIGURE 11
Geographical distribution of phytoplankton
abundance on all cruises, Lake Huron.
-------
181
LAKE MICHIGAN
CRY
CHR
CHL
X
CO
ml
NORTH
SOUTH
-J
bJ
O
BAC
0.5
TOTAL*
40
CYA
20
STATION
FI6URE 12 Annual geographical distribution of major algal
divisions In Lake Michigan. BAC * Bact I larlophyta,
CHL ¦ Chlorophy+a, CHR ¦ Chrysophyta, CRY ¦
Cryp+ophy+a, CYA ¦ Cyanophyta, PYR ¦ Pyrrhophyta.
-------
LAKE MICHIGAN
Aug. 3-4
Aug. 17-19
Oct. 12-15 *
Oct. 26-30
SOUTH
April 17-21
May 4-6
NORTH
-i—I—I—|—I—I—I—I—I—T
77 64 57 47 41 34 27 23 18 II
STATION
FIGURE 13
Geographical distribution of phytopIankton
abundance on all cruises. Lake Michigan.
-------
183
1000
750-
500-
250-
o flnacysti* montana
v. minor
x figmenellum
quadruplicate
J J ft
MONTHS
r
v
a
UJ
CO
e
=>
X
80 +
60-
o Cotmarium %p.
x Oocyst!* borgei
J J ft
MONTHS
_i
E
V.
at
UJ
a
E
Z>
Z
B
o Coccochloris peniocystis
2000 x Coelosphaerium naegelianum
1560
1000
500-
J J ft
MONTHS
800
600-
Co#lastruft
microporum
Monoraphidium
contortu*
J J ft
MONTHS
500
400
V 300
DC
UJ
tt 200
3
X 100
0
ftphanizoAtnon
flos-aquae
9—0-
J J ft
MONTHS
r
s
a
UJ
CD
X
D
X
Pediastr-um simplex
v. duodenarlum
rtougeotia sp.
J J ft
MONTHS
FIGURE 14
Mean seasonal distribution of a) Anacystls montana
y. minor and Aqmanallum quadrupllca+um. b) Cocco-
Chlorls penlocystls and Cn«lttspha«rlii.n naapal lannm.
c) AphanlKHMnQn f iQS-OqUM. d) Cosmarlum and
Oocyst Is borflflli e) Coelastrutn mlcropnrum and Mono-
raphldlum contortum, f) Padiastrum cimfiov V|
duodanar 1 unri and Moupectia sp.f Lake Erie.
-------
184
400 +
300 T
-J
£
£ 200
ffi
c
z 100-
0+
Haptophyte sp.
100 +
J J ft
MONTHS
-i
n
\
DC
Hi
00
c
3
Z
o Rhizosolenia sp.
x Fragiiaria capucin.
J J A
MONTHS
1000
x Rhodomonas minuts
v. nannoplanktica
o ChrooAorta* norstsdtii
B
800 +
\ 600
£ 4001
J J ft
MONTHS
r
\
a:
LJ
CD
r
zt
z
flctinocyclu's normanii
f. tubsalsa
J J fl
HONTHS
100 ¦
80'
_r
s
s
60
OL
ID
CD
C
40
3
Z
20
0
o Stephanodi*cu«
niagarae
x Stephanodiscus
binderanus
10"
e
_)
r
e
a
UJ
0Q
4 ¦
c
3
Z
2
0
J J ft
HONTHS
C«raiiun hirur\dinell»
J J ft
HONTHS
FIGURE 15
Mean seasonal distribution of a) Haptophyte sp.,
b) Rhodomonas ml nut a. nannoplanktfca and Chrnr^^.
norstedtii. c) Stephanodlscus niagarae and staph»nn-.
iLLs£U& binder anus, d) RhUcsolenla and Frapti»r.[n
CflPUClna. a) Actlnocyclus nermann f- subsal«tn,
f) Ceratlum hlrundtnallfl> Lake Erie.
-------
flnacystis Marina
TIME
185
Oscillatoria tenuis
Oscillatoria linnetica
r
s
Qt
111
OS
c
3
Z
FIGURE 16
Seasonal and geographical distribution of a) Anacystis
b) QscMlBtorla tenuis, c)
XJjUfltlcA* Lake Erie.
-------
186
Merismopedia
tenuitsima
Osci1latoria
subbrewis
ScertedttAus
•cornis
FIGURE 17
Seasonal and geographical distribution of a) jttacisnB?
pedfa tenulssfma. b) OscM latnrtu subrei/lc;,. c)
Scenedesmus acorn Is. Lake Erie.
-------
Cryptomonas erosa
187
Fragilaria crotonensi*
Tabellaria flocculosa
FIGURE 18 Seasonal and geographical distribution of a) Crypto-
jbqoas. fiCQ&a* b) Fragilaria crotonensis, c) Tabai laria
floeeulosa. Lake Erie.
-------
Melosira granulata
FIGURE 19
Seasonal and geographical distribution of Melo^ir^
granulata. Lake Erie.
-------
finacystis marina
Rhodomonas minuta v
nannoplariktica
MONTHS
MONTHS
3000
2500
g 2000
v
£ 1500
CO
§ 1000
X
590
0
Coccochloris
peniocystis
B
/
_L
J-
-L.
M J J fl
MONTHS
1200
-j
JET
\
o:
ui
(a
E
3
Z
800
400'
flnacysti s
moritaria v. minor
- ¦ t i i _ > . i
ft M J J fi S 6
MONTHS
300
J
£
200
0£
Ui
ffl
e
3
100
Z
o ftnacyst^ ih*r«alis
x Co«losphaerium
naegelianum
J J fi S ' 6
MONTHS
JE
V
K
UI
00
E
3
Z
o Cryptomonas erosa
x Cryptononas
erosa v. reflexa
MONTHS
FIGURE 20
Mean seasonal distribution of a) Anacys+tg marina.
b) Cpccochlnrlfl Pflnlocystls. c) Anacystls thermal Is
and COfllOSPhaftTlmn naoflfllfanum, d) Rhedomnn** mlnuta
ym nannoplnilKtlcn, •) Anacys+ls Montana v. minor.
f) CryptniOTiaa troin and Cryptaronns firn^n refiayar
Lake Huron.
-------
190
Cryptomorias
pyrenoidifera
J J
MONTHS
\
ex.
U
CD
r
3
z
1+
2t
o Stephanodiscus
niagarae
x Stephanodiscus
transi]wani cut
M
J J ft
MONTHS
t o
Cyclotella
cowensi s.
Cyclotella
cocita
B
J J fl
MONTHS
100 +
E
S
cm
ui
00
e
3
1
Tabellaria
f locculosa
x Tabellaria
flocculosa
v. linearis
J J ft
MONTHS
£
\
ID
CD
Z
o
z
120 +
9®
40
Cyclotella
kuetzingi ana
v. planetophora
Cyclotella
ocellata
Rhizosolenia sp.
MONTHS
£
\
a
UJ
OQ
e
3
Z
MONTHS
FIGURE 21
Mean seasonal distribution of a) Cryp+omormg pyre-
no id if era. b) Cyclotella comensls and Cyclntftll»
comta. c) Cyclotel la kuetzingiana v. oianetophor* and
AyrIotaIla oral lata, d) StfiphanodISCUS nIaqaraa and
stephanodtseus trnnslIvanlcus. e) Tabellarla
flocculosa and TabelI aria flocculosa Y«. II nearly
f) RhItosoI en I a Lake Huron.
-------
191
Chrysosphaerella
longispin*
Q—e-
i
rt
J J B
HONTHS
-J
E
\
0£
Ui
00
£
Z>
Z
68 +
40-
20-
0.
Fragilaria
crotonensis
_L
J J ft
MONTHS
-J
c
V
UI
ffi
s
z>
X
60| o Dinobryon divergens
x Dinobryon cylindricum
40
B
20-
1 FTj ] fl~s 6"
MONTHS
E
\
at
bi
ffi
z
Melosira
itlandica
ft' w'J'J 'ft'fc '6
MONTHS
300
Dinobryon socials
v. americanum
5 100
J J R
MONTHS
FIGURE 22 Mean seasonal distribution of a) Chrysosphaarai>«
long Ispina, b) Dinobryon dlvflroens and Dinobryon
cylIndrleui. c) Maloslra Islanritca. d) Frag!I aria
rrfltonnntic. Lake Huron.
-------
192
Rs-ter ionel la for«o-sa
Osci 1 lst-oria limnetica
Coccochlori* el*b*ns
FIGURE 23
Seasonal and geographical distribution of a) Asterlo-
nella farmosa. b) Oscillatorla ic> QarJ^l^
chlorls Blabans. Lake Huron.
-------
193
Fragilaria intermedia^
v. faliax
\
a.
ui
to
Haptophyte *p
FIGURE 24
Seasonal and geographical distribution of a) Frag|-
larla tntarmadia v. fall QX, b) HflptOPhy t flJSgi«
Lake Huron.
-------
194
3000f o Coccochioris
peniocystis
Rnacystis
Montana
v. minor
K 3000
2000
1000
J J ft
MONTHS
^ 130
oc
UJ
00
E 100
Z>
z
50
0
o Stichococcu* sp. "
x donoraphidiuw contortu*
J J ft s
MONTHS
300 +
-1
s
200
s
at
UJ
CO
z
D
100
Z
0«ci11at-or i a
agardhi i
Coelosphaerium
naegel ianuoi
B
J J ft
MONTHS
408 t
Dinobryon divergent
Dinobryon social?
v. anericanun
o Dinobryon cylindricum
ui 208
J J ft
MONTHS
800 t
600
r
\
a:
U! 400
at
£
3
Z 200
o Gomphotphaeria lacu«tri«
x Oscillatoria limnetica
ft N
J J ft
MONTHS
J
r
\
a
UJ
CO
E
3
r
600
400
200
o Chroomonas norstedtii
x Rhodomonas mim/ta
v. nannoplanktica
J J ft
MONTHS
FIGURE 25
Mean seasonal distribution of a) Coccochioris penlo-
cy st Is and Anacyst 1 s montana v. ml MM", b) OflfllQ-
ctphaerlum njiagal lanum and Qscl I Ifltortfl agardhi 1,
c) pftmphftsphaeria Iflcustrls and QsclIlatorla
>Imnetlca. d) Stlrhnrnccus and MonOraphldlUm
mntortum. e) Dinobrvon diveroens. Dinobryon .socials
yu »mftrlranum and Dinobryon ry11nrirlCUff). f> Chroomnnns
nnrstedt I I and PhftHomnnas mlnuta nannop I ankt ,
Lake Michigan.
-------
195
10 •
o Cryptomona*
warssoni i
x Cryptomonas
pyrer\oidif *ra
ft N J J ft S 0
MONTHS
je
\
0£
bJ
CD
E
3
Z
2-
0-
o Stephanoditcus
niagarae
x Stephanodiscus
transilvanicus
«
J J ft
MONTHS
160
120-
80-
40-
B
Cyclot«lla
comensis v. 1
Cyclot.s-11* comta
0_§=t
ft N J J ft S
MONTHS
-j
E
S
tt
Ul
CQ
E
3
Z
labell*ri*
fenestrate
Tabellaria
flocculot*
J J ft
MONTHS
60 +
40
20-
Cgcloiella michiganiana
ftsterioneUa fornosa
MONTHS
230f o Fragilaria crotonensis
x Fr«gil«ria
-------
196
Melosira italica
sub%p. subarctica
Melosira islandica
200 t
80
0
ft
MONTHS
Osci1latoria
1imnet ica
-j
s
*\
B
Tabellaria fenestrata
40"
30-
20-
10.
0-
Styloth«ca aurea
ft N
J J ft
MONTHS
FIGURE 27
Mean seasonal distribution of a) Mfclosira italir?
Bubsp. stibarctica and Hftlflflixa ielandiCfl . b) Stvln-
> 1 imnetita ¦ d) Tabol-
t-iiecfl aurea. •
•] ^ria
c) fl«f 'ill af nr ifl
, Lake Michigan
-------
197
Rhizotoltnia
»rien»i»
FIGURE 28
Seasonal and geographical distribution of a) An«cy«+t^
AfiLlQA# b) HaptQPhytft &&U» c) Rhliaaclenta erl«ns»sr
Lake Michigan.
-------
198
LAKE ERIE
LAKE MICHIGAN »
500
LAKE HURON »
400 -
o
o
o
X
300
LlI
CJ>
I 200
z>
CD
<
100
a. LONG TOW
1983
FIGURE 29 Seasonal zooplankton abundance In Lakes Erie, Huron
and Michigan. Short hauls are plotted.
-------
199
W
o
o
o
LU
O
z
<
o
CD
<
300 -
200 -
100 -
LAKE ERIE
/
1983
FIGURE 30
Seasonal distribution of zooplankton groups In Lake
Erie. Short hauls are plotted. COP ¦ Copepoda
nauplll9 ROT * Rot Ifera, CAL ¦ Calanolda, CLA *
Cladocera, CYC * Cyclopolda.
-------
200
*>
<
a
=>
CD
<
100 -
80 -
o
o
o
- 60 -
UJ
o
40 -
20 -
LAKE MICHIGAN
1983
FIGURE 31
Seasonal distribution of zooplankton groups In Lake
Michigan. Abundances from short hauls are plotted.
COP ¦ Copepoda nauplll, ROT ¦ Rot Ifera,
CAL * Calanolda, CLA * Cladocera, CYC ¦ Cyclopolda.
-------
201
LAKE ERIE
40 - WEST
EAST
CALANOIDA
30
CLADOCERA
20
10
2 80
CYCLOPOIDA
NAUPLII »
s 60
CO
< 40
20
TOTAL
400
ROTIFER A
200
78 79
9
STATION
FIGURE 32 Geographical distribution of major zooplonkton
groups In Lake Erie.
-------
202
12
8
m
1
O
o
X
CO
2
0}
z
<
CD
o:
o
6
5
A-
3
2
I
30
20
10
LAKE HURON
CALANOIDA
CLAOOCERA
CYCLOPOIDA
NAUPLII
J L
_L
J L
TOTAL
ROTIFERA
SOUTH
NORTH
-|—i—i—i—i—i—i—i—i—r
61 54 45 37 32 27 15 12 9 6
STATION
FIGURE 33
Geographical distribution of major zooplankton
groups in Lake Huron.
-------
203
LAKE MICHIGAN
CALANOlDA
CLADOCERA
4 -
CYCLOPOIDA »
10
NAUPLII
o
o
o
x
CO
2
CO
TOTAL
80
60
40
20
SOUTH
NORTH
STATION
FIGURE 34
Geographical distribution of major zooplankton
groups In Lake Michigan.
-------
>
o
Z
Ui
Z)
G
UI
IX
U.
.4
.v . 3
0J
1
204
LAKE ERIE
i.e 1.5
SIZE CLASS <*«>
2.Q
.4
. 3
i
>
o
z
Ui
3
G
Ui
K 1
U. * 1
.2
Ha
J
M
LAKE HURON
. 1
2SE n^_
.5 1.0 1.5 2.0
SIZE CLASS (mm)
FIGURE 35
.v
>
o
z
Ui
3
a
Ui
IX
u.
LAKE MICHIGAN
J.5 2.0
SIZE CLASS (mm)
Size-frequency distribution of zooplankton In Lakes
Erie, Huron and Michigan. Short hauls are plotted.
The 0.1 size class refers to the 0.1 to .199 size
range.
-------
205
Oiaptomus
2000 siciloides
£ 1508
ui
£
O
M
CD
=>
O
\
1000
900
J J ft
MONTHS
12000
QC
UJ
K
U)
r
9000
6000
tt
g 3000
0'
Chydorus *phaericus
Eubosmina coregoni
J J ft
MONTHS
16000
£j 12000
~-
c
„ 8000
H
CD
O 4000
0
B
o Calanoid - copepodite
x Cyclopoid - copepodite
J J R
MONTHS
K
Ui
h
Ui
CO
®
00
3
o
\
10+ X
o
Diaphanosowa
leuchtenbergianum
Oaphnia
retrocurva
J J ft
MONTHS
Of
UJ
H
UI
o
s
*
70'
60
A
50-
e
©
40
6>
*-«
X
30-
V
se-
ta
0-
Copepoda nauplii
J J ft
MONTHS
3000
Asplanchna priodont#
J J ft
MONTHS
FIGURE 36 Mean seasonal distribution of a) Diap+ftmng siciioidAg,.
b) Calanoid - copepodite and Cyclopold - copepodite,
c) Copepoda nauplll, d) Chvdorus «ph»x>rir..c and
EubPSflltna coregoni, •) Dlaphanflftftm* Iauch+ftnhftrfll»r>1,.p
and Daphnla rBtrocurva, f) Ast>n>nrhW» Priedontn.
Lake Erie.
-------
ct
LU
(if
E ®
©
U ©
>-• »-•
CD X
=> v
O
\
601
50i
40|
30-
20-
10-1
Conochilus unicornis
Colloiheca sp
J J ft
MONTHS
206
28
K
Ul
1-
U)
r
®
o
®
H
*•* 10
CD
X
3
V
O
V
•
Keratella
crassa
J J A
MONTHS
K«llicottia
longispina
Ploesowa sp.
B
J J ft S
MOHTHS
u.
Ill
h
Uj /v
E £
u ®
1-t '-I
fiQ X
3 ~
O
v.
24
16 +
8+
0T
o Notholca
laurentiae
Notholca
squamula
J J ft
MONTHS
at
ui
h
m ^
e ®
s
u ®
~1
at x
o
s
#
30 +
40
30 +
20+
10
0T
Ktratflla
cochl«»ri»
K«rai«ll»
quadrat*
M
J J ft
MONTHS
bi
Ul A
E £
CD
(J ®
M «"<
CD X
D v
(J
\
•
20-
15
10
0
Notholca foliacea
J J ft S
MONTHS
FIGURE 37
Mean seasonal distribution of a) Conochllus unlearnt*
and firtiin+heca sp.. b) KelIIcpttla longtspina and
Pt rtnsama so.. c) Kflrfltellfl COChlflarlS and Kera+al I»
quadrata. d) Kerfltel la crassa. e) Notholca Iauren-Hap
wnri Natholca sauamuI a. f) Notholca fo11ACQS. Lake Erie.
-------
207
oc
ID
h-
Ul
£
100 0 Polyarihra
dolichoptera
x Poluarthra
vulgaris
at
D
O
\
®
CD
©
H
x
v
J J ft s
MONTHS
2'" o fiscoaorpha ecaudi«
x flscoAorpha *p
U <9
J J ft S
MONTHS
12t
B
CL
UJ
U1 A
s
y CD
f *"•
CO X
D v
O
\
Polyarthra
major
J J ft
MONTHS
16000
Daphnia galaeta «endotae
£l2000 ¦
0000 -
o 4006-
J J ft S
MONTHS
oc.
bJ
ui
* £
(D
O 6
1-4
(B X
3 v
O
\
16 +
~ 12"
Gastropu* %lylifer
J J ft S
MONTHS
4000
UJ 3000-
h
U1
u 2000-
tH
CD
D
? 1000-
*
0
Bosmina longirostris
M J J ft S 0
MONTHS
FIGURE 38 Mean seasonal distribution of a) Polvarthra dnliehop
£££& and golyarthrfl v»T?arifi. b) Polvarthra nwpnr.
c) Gastrnpufi fitylifer« <0 Aacoranrph* ecaudia and
Ascomnrphfl sp., e) Daphnia galftara i"*ndn»«P ,
f) Bosaina lonyirftfifria , Lake Erie*
-------
208
Diaplomui or«gonensi«
A
METER
ndJ\ .
u
1 A u/)\ax\J\
CO
3
o
\
*
14
Cyclops bicuspldatus thomasi q
oc
Ui
ui
r
o
Tropocyclop* prasinu* C
arxicanu*
Q£
UI
H
UI
c
o
at
D
O
V
*
FIGURE 39
Seasonal and geographical distribution of a) PlaptomiLS
^.nononfiis. b) fiyctops h\c.usnIdatus thomasi* c)
Trnpm,c'°Ps prft
-------
209
Mesocyclops edax A
c*
UJ
t-
UJ
c
o
CO
=>
o
\
Brachionus sp
FiJina longi«»t«
ee
bl
H
U1
r
u
»-#
-------
210
Svjnchaeta tp
Seasonal and geographical distribution of a) Kar»+g||n
flnrl Inae. b) Synchaeta ssu, c) Trlchocerm cvi »»Hr|rn
Lake Erie.
-------
211
Keratells hiemali*
Brachionus
caudatus
FIGURE 42
Seasonal and geographical distribution of a) Trlcho-
Cflrca multrlclnla. b) Kara+alta hlamaIfs. c) Rrwchlo-
mis caudatus, Lake Erie.
-------
212
Oiaptomus ashlandi
1000
400
200'
J fl S
MONTHS
a.
UJ
h
Ul
£
O
•H
CO
ZD
o
\
*
8008
6000
4800 -
2000
o Cyclopoid - copepodite
x Cyclops bicuspidatus
thomasi
N J
J ft S
MONTHS
B
200
100.
o Diaptomus oregonensis
x Oiaptomus sicilis
J J fl S
MONTHS
a
ui
t-
UJ
r
o
M
CO
3
a
*
400 o Tropocyclops prasinu*
mexicanus
300"
200
100
x Mesocyclops edax
J J fl S
MONTHS
o Calanoid - copepodiie
x Copcpoda nauplii
®
is
J J ft S
MONTHS
oc
Ui
H
U1
E
CD
D
U
\
*
1200
800
400-
o Bosmina longirostris
x Daphnia tchodleri
J fl ft
MONTHS
FIGURE 43
Mean seasonal distribution of a) Dlaptomus ash I andif
b) Di»ptr>mus oreaonensls and Diaotomus stcinsr C)
Calanoid - copepodlte and Copepoda nauplll, d)Cyclo-
pofd - copepodlte and Cyclops bfcuspfdatus r,
e) Trnpocyclops praslnus mexlcanus and Mesocyrlnpc
adax. f) Bosmina |pnflITOStfIS and Danhnta schorilar^
Lake Huron.
-------
1600 0 ^aphnia qalaela Mendoia
x Oaphnia pulicaria
1200
800"
460
J J ft S 0
MONTHS
213
4000
Keratella cochlearis
Li 3000
o 2000-
J ft S
MONTHS
Eubotnina coregoni
500'
250
HONTHS
300+ o Keratella crassa
x Keratella earlinae
fi + Keratella quadrats
tL 200"
H J J fi 6 0
MONTHS
1000
750 • ¦
500
250
o flsplanchna priodonta C
x Collotheca sp.
n J J R 6 0
HONTHS
a
u
H
U)
r
D
a
\
2400 o Noiholca laurentiae
x Noiholca squanula
1000 '
1200
600
0
J J ft S
MONTHS
FIGURE 44
Mean, seasonal distribution of a) Daphnla galaeta man-
jlttta and Paphnla pul(carla. b> Eubosmlna coregoni,
c) Asplanchna prlodonta and Collothaca 5a.» d> Kara-
te! la cochlears, e) Keratella crassa, Keratella
earlInae and KeratelI a quadrate, f> Nothoica lauran-
±iaa and Notholea sguamuI a. Lake Huron.
-------
214
200
130
o Polyarthra dolichoptera
x Polyarthra «*jor
10©
50-
e
J R S
MONTHS
6000
B
Polyarthra vulgaris
4000
§ 2000
o
0 L
M
J ft 6
MONTHS
2400
S 1600
1200
600-
o Gastropus stylifer
x Synchaeta sp.
j ft 6
WQKTHS
FIGURE 45
Mean seasonal distribution of a) Polyarthra dOI(Chap-
ter a and Pnlyarthra major, b) Pfliyflrthrfl VUlflflrlS.
c) R»ig+roDus styi i far and Synchaeta Lake Huron.
-------
215
OiaptoMUt ttinutut
Qaphnia retrocurv®
FIGURE 46
Seasonal and geographical distribution of a) Dlaptomus
mlnntus. b) Daphnla retrocurva. Lake Huron.
-------
216
Conochilus unicornis a
tt
ui
H
Ui
E
a
00
3
O
\
*
ac
ui
»-
Ui
£
O
ffi
=>
U
\
•
FIGURE 47
Seasonal and geographical distribution of a) Cono-
chiius unicornis, b) KeMlcpftla long Ispina. Lake
Huron.
-------
3000 t
Diaptomu* ash1 andi
2800 4
o 1000
u
\
0
J J ft
MONTHS
217
8000 f
Cyclopoid - copepoditc
UJ 6000
4000
2000
J J A
MONTHS
B
ac
uI
h
Ui
0
3
a
\
800 +
600 4
400 4
200 4
o Oiaptomus minutus
x Diaptowu* oregonentit
+ Limnocalanut «acruru»
J J ft
MONTHS
oc
Hi
K
Ui
r
o
3000 t ° Cyclops bicuspidatu*
thomasi i
x Tropocyclops prasinus
, ftexicanus
2000 4
£° 1000
o
s
•
0+ X**
J J «
MONTHS
ot
in
is -
r ®
o
o ®
H H
n x
o
\
20+
134
104
34
0i
o Calanoid - copepodite
x Copepoda nauplii
FIGURE 48
J J A
MONTHS
8
o Daphnia Qalaeta aendota
2000+ x Daphnia pulicaria
u 1500 +
1800 +
J J R
MONTHS
Mean seasonal distribution of a) Dtaptomus ash I and 1.
b) Diap+nmus minutus. Dfaptoinus oraoonansls and
L tmnocalanus macrurusf c)Calanold - Copepodite and
Copepoda nauplll, d) Cyclopoid - copepodite, e)
Cyclops bfcuspldatus thomassl and Tropocyclops ppfl-
slnus maxlcanus, f) Daphnta gataa+a manrio+a and
Daphnia puiicar la. Lake Michigan.
-------
218
K
UJ
ui
r.
m
3
O
\
~
1000
750-
500-
250
o Euboswina coregoni
x Holop«diu» gibberom
J J fl
MONTHS
oc.
UJ
UJ
©
s
00
¦D
o
V
*
bt
2-
o Collotheca sp.
x Conochilus unicornis
H
J J ft
MONTHS
tt
UJ
i-
Ui
E
U
CD
3
L>
\
500
400
300
200
100
0
B
fls.pl anchna priodonta
N
J J ft
MONTHS
en
UJ
H
UJ
z;
00
D
(J
s
*
©
v
MONTHS
FIGURE 49 Mean seasonal distribution of a) Eubosmlna coregont and
HnlQpfldlUffl Olbberum. b) Asplqnchnn prtodont»r C) Syn-
chaeta sp** d) Collotheca so*, and Conoehiiuc unicor-
nis. e) Kelt lCQttta long I spina and Gastropus sty I I ¦farr
f) Keratella earlInae and Keratella quadratar Lake
Michigan.
-------
ec
tij
h
iij "•
X ®
s
o ®
H
CD X
3 v
a
\
o Keraiftlla cochlear it
x Keratella crassa
J J ft
MONTHS
219
oc
ui
t—
uj ^
X ®
(0
O ©
t-i —
CD X
D v
(J
0 •
Polyarihra
vulgaris
M
J J ft
MONTHS
tt
u
hi «
X ®
s
o ®
H
IB X
3 v
O
\
B
o Polyarihra dolichopiera
x Polyarihra major
MONTHS
Ot
Ul
h
Ul
CD
Z>
u
\
1000
800
660 4
400
200
o Asconorpha *p.
x Ploetona »p.
M
J J fl
MONTHS
FIGURE 50 Mean seasonal distribution of a) KerataIia cochIearIs
and KarateIIa CrBSSB. b) Pfllyarthra dolIchnp+ara and
Pnlyarthra major, c) Polyarthrfl VUlflBrlS, d) ASCOBT
orpha sp. and Pioasoma sp.. Lake Michigan.
-------
a:
UJ
i-
IU
E
o
0)
D
o
\
«
220
B
Bosmina
longirostris
Daphnia rrirocurva
FIGURE 51
Seasonal and geographical distribution of a)
Sl I Ids, b) Bosmtna Ionq 1 rostr»s. c) Daphnta retro-
cur vaf Lake Michigan.
-------
221
Notholca iaurentiae
Notholca squamula
Notholca foliac«a
FIGURE 52
Seasonal and geographical distribution of a) Notholca
laurentipfl. b) Nothoica squamula. c) Motholea fol-
Iacaaf Lake Michigan.
-------
222
MONTHS
Seasonal fluctuation of weighted mean phytoplankton
blomass In 1970 and 1983, Lake Erie. 1970 data modified
from Munawar and Munawar (1976). Values are corrected
by using the weighting factors of 15.6f, 59.6% and 24.6?
for the western, central and eastern basins (after
Munawar and Munawar 1976).
-------
223
1974 O
3000
1963 »
E
\ 2000
to
-J
-J
UJ
o
1000
MONTHS
FIGURE 54 Seasonal abundance of phytopIankton In southern Lake Huron.
Data from 1974 (Section 8) are modified from Stoermer and
Krets (1980). The 1983 seasonal abundance data from this
study have had the density of Anarys+tc marina and
CPCCQChlorlS nan lacy stu subtracted. 1983 data from
southern Lake Huron only (Stations 27,15,12,9,and 6).
-------
224
1971
io
E
o»
tn
in
<
Z
o
ffi
1.0
0.5
1983 - Average
1983 -Maximum
' J ' A ' s ' 0 '
MONTHS
M
N
FIGURE 55 Seasonal abundance of phytopIank+on In Lake Huron In 1971
and 1983. Data are modified from Munawar and Munawar (1982)
and this study. Maximum represents the upper limit of the
range of seasonal blomass for ten stations In 1983.
-------
225
OCTOBER 16 - 18, 1983
* * TOTAL
A ~—« DIATOMS
0.5
AUGUST 18-21, 1983
0.5
TOTAL
DIATOMS
E
JULY 2-4, 1983
S
o
S
TOTAL
DIATOMS
6,5445373224 15
9
STATION
FIGURE 56
Mean seasonal distribution of total algal and diatom blomass
on selected dates, Lake Huron, 1983,
-------
C£
LJ
o:
uj
CD
240 j
200--
160-
120-
80-
40-
\
o 1970
x 1983
ot
*^r"
M
\
\
"O
0 N 0 J
Figure 57 Mean abundance of crustaceans In Lake Erie In
1970 and 1983. 1970 data are modified from
Watson and Carpenter (1974).
N)
to
On
-------
227
480 -
5 140
CLADOCERA
1939 •
1949 ~
1959
1961*
1970 ©
1983 0
(All basins)
1983 »
(Western bosin)
~ 120
a: 100
A ' M ' J ' J ' A S
MONTHS
Figure 58 Mean number of cladocerans In Western Lake Erie from 1939 to
1983. Sources: 1939-Chandler (1940); 1949-Br9dshew (1964);
1959-Hubschman (1960); 1961-Brltt e+ a!. (1973); 1970-Nalepa
(1972). Modified after Naiepa (1972) and Gannon 1981.
-------
228
320
a:
LxJ
h-240
o:
UJ
CD
160
80
1939 •"
1949
1961*-
1970 g-
C0PEP0DA
1983 a B
(All bosins)
1983 » r>
(Western basin)
MONTHS
Figure 59
Mean number of copepods In Western Lake Erie from 1939 to
1983. Sources: 1939-Chandler <1940); 1949-Bradshaw (1964);
1959-Hubschman (I960); 1961-Brltt et at. (1973); 1970-
Nalepa (1972). Modified after Nalepa (1972) and Gannon
(1981).
-------
229
700 -
600 -
500 -
ce 400
LU
I-
300 -
200 -
en
Ld
CD
100 -
ROTIFERA
1939
1961*-
1970 o-
1983 a-
-o
(All basins)
1983 t> t>
(Western basin)
A 1 M 1 J 1 J
MONTHS
Figure 60 Mean number of ro+lfers In Western Lake Erie from 1939-1983.
Sources: 1939-Chandler (1940); 1961-Brltt et at. (1973);
1970-Nalepa (1972). Modified after Nalepa (1972) and Gannon
(1981).
-------
230
1971 -k
1974 »
1983 +
80
20
MONTHS
Floure 61 Mean number of crustaceans exclusive of copepod naupl If) In
Figure oi ^ ^ 19?4 an(J lgg3< Da+a are mod|f I©d from
Watson (1974), McNaught et al. (1980) and this study.
-------
231
400 -
300 -
QC
LlI
tr
UJ
m 200
100 -
1974 ®
MONTHS
Figure 62
Mean number of rotifers In Lake Huron In 1974 and 1983. 1974
data was modified from Stemberger el al. (1979).
-------
232
4000
Notholco laurtntiM #-
Notholca foliocta
Natholea iquamula
-~ -
2000
4000
J & 2000
Dlaplomu*
Limnocoianut macrgru*
Holaptdium gibb*rufn<|
77 64 57 47 34 27 23 ® II 6
STATION
Figure 63 Geographical distribution of t imnocalanus macrurnc,
niwptomui slcllIs* hoIQpedlum glbberum, Bosmin*
inngirostris. Eubosmfna coregonU Notholca
Iaurenflae. squamula and fQIlaCSfl, Lake
Michigan
-------
SPECIES LIST - LAKE ERIE PHYTOPLANKTON (1963)
233
UIV TAXON
AUTHORITY
bAC Achnanthes
Achnanthes
Achnanthes
Ac h nan tne s
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Ac t i nocycI us
Act i nocyc I us
b i a so Iet t iana
b i ore t i
c t e v e i
clevei v. rostrata
consp icua
ex igua
haick i ana
lanceolata v. dub i a
I emnrerirann i
i i near i s
linearis f o. cu r ta
microcephala
m i nut i ssima
sp.
s p • ?
sub Iaev is
r.orman i i f. subsa I sa
sp.
Amphora ovalis v. affins
Amphora ovalis v. pediculius
Amphora perpusitla
Amphora sp.
Amphora tenuistriata
Anomoeoneis vitrea
(Kutz.) Grun.
Germ.
Gr un.
Hus t •
A. Mayer
Grun.
Grun.
Grun.
Hust •
(M. Sm.) Grun.
H . L• Sm.
(Kutz.) Grun.
Kutz .
Hust.
(JuhI.-Dannf.) Hust.
(Kutz. ) V.H. ex DeT.
(Kutz.) V.H. ex DeT.
(Grun.) Grun.
Mang. in Bourr. £ ttang
(Grun.) Pair. £ Reim.
Asterionella forrrosa
Hass.
Ca 1 one i s
bacillaris v. thermalis?
Ca1 one i s
bac i 1 1 uir
(Grun.
) Ci.
C a 1 one i s
hya1 i na
Hust.
Ca 1 one i s
ventricosa v. minuta
(Grun.
) Mills
Coc c on e i
s d i m i n u t a
Pant .
Coccone i
s ped i cu1 us
Ehr .
Coccon e i
s placentula
Ehr •
Cocconei
s placentula v. euglypta
(Ehr •)
C 1.
C oc c on e i
s placentula v. lineata
(Ehr.)
C 1.
Coccone i
s sp.
Cose inod
i scus lacustr i s
Grun.
C y c 1 o t e 1
la antiqua?
M. Sm.
Cyc1ote1
la atorrus
Pant.
Cyc1ote1
la atorcus?
Pant.
Cyc 1 ote1
la corcensis
Gr un.
Cyc 1 ote1
la comensis v. 1
Cyc1ote1
1 a comensis v. 2
Cyc1ote1
la comta
(Ehr.)
KutZ .
Cyc1ote1
1 a corrta v. o 1 igact is
(Ehr .)
Grun.
C yc1ot e1
la crypt ica
Reim.
et a 1 •
Cyc 1 ote1
la gamrra
So v.
Cyc 1 ote(
la kuetz ing iana
Thw •
Cyc 1 ote1
la kuetzingiana v. planetophora
Fr i eke
Cyc 1 ote1
ta Kuetzingiana v. planetophora?
Fr i eke
Cyc 1 ote1
la menegh in iana
Kutz.
Cyc1ote1
la m i ch i gan iana
Sk v.
Cyc 1 ote1
la oce11ata
Pant.
-------
234
SPECIES LIST - LAKE ERIE PHYTOPLANKTUN (1983)
UIV TAXUN AUTHORITY
bAC CycIotel la
CycIote I la
CycIoteI la
CycIote I la
C yc I o t e I I a
CycIoteI la
Cymatop I eura
Cymatop I eura
op ercuI a ta
pseuaostel Iigera
sp .
sp • # I
st eI I i ge ra
mo Iter ec K i
so I ea
soIea v
ap i cuIata
es iaca
auer s waId i i
CymbeI I a af f i n i s
Cymbella micrccepha I a
Cymbe I I a m i nuta
Cymbella minuta v. si
Cymbella prostrata v.
CymbeI I a pus i I I a
Cymbella sp>
Denticula tenuis v. crassula
D i atoma ancep s
Diatoma tenue v. elongatum
0 i atoma vu I ga re
D i p I one i s ocu I ata
Entomoneis ornata
Fragilaria Drevistriata
Fragilaria brevistriata
F r ag i I ari a capuc i na
Fragilaria construens
Fragilaria construens
Fragilaria construens
Fragilaria construens
Fragilaria crotonensis
Fragilaria intermedia v
Fragilaria leptostauron
Fragilaria leptostauron v.
Fragilaria nitzschicides
Fragilaria pinnata
Fragilaria pinnata v.
Fragilaria pinnata v.
Fragilaria sp*
Fragilaria vaucheriae
cIeve i
d i chotomum
par vuI urn
sp.
tergest inum
a ttenuatunr.
nf lata
v• minuta
v. pum iI a
v. venter
f a I lax
dub ia
Iancettu la
pi nnata
Gomphoneira
Gomphonema
Gomphonema
Gomphonema
Gomphonema
Gy r os igma
Gyrosigma scictense
Me I os i ra agas s i z i i v
Me I os i ra distans
Melosira distans v. limnetica
Me I os i ra granu I ata
Melosira granulata v. angustissima
Melosira granulata?
Melosira i sI and i ca
ma I aye ns i s
(Ag.) Kutz.
Hust •
(CI. I Grun.) V.H.
Hust •
(breb. Z. Godey) W. Srr.
( W. Sm.) ka I f s
Kutz •
Gr un •
Hi I se
(Bleisch) Re i m »
(Rabh.) Re i in .
Gr un •
(Nag.) k • & G.S. West«
(Ehr.) Kirchn.
Lyngb.
Bo r y
(Breb.) CI•
t J *W. Bait*) Keim.
Gr un.
(Pant.) Hust.
De sm.
(Ehr.) Grun .
Temp. L Per.
Grun.
(Ehr.) Grun.
K i tton
(Grun.) Stoerm. C Yang
(Ehr.) Hust.
(Grun.) Hust.
Grun.
Ehr.
(Schum. ) Hust.
(Kutz.) Peters.
Fr j eke
Kutz.
Kutz .
(Grun.) Fr ieke
(Kutz.) Rabh.
(Sulliv. t. Wormley) CI*
Ostenf *
(Ehr.) Kutz.
0. MuI I.
(Ehr.) kaIf s
0. Mull.
(Ehr.) Ralfs
Q. MuI I.
-------
235
SPECIES LIST - LAKE ERIE PHYTOPLANKTDN (1963)
DIV T AXON
AUTHOR ITY
BAC
Me I os i r a
Me I os i ra
Nav i cu
Na v i cu
Nav i cu
Nav i cu
Nav i cu
Na v i cu
Na v i c u
Nav i cu
Nav i cu
Nav i cu
Na v i cu
Nav i cu
Na v i cu
Nav i cu
Nav i cu
Nav i cu
Nav i cu
Nav i c u
Nav i c u
Nav i cu
Na v i cu
Ma v i c u
Nav i cu
Nav i cu
Nav i cu
Na v icu
Nav I cu
Nav i cu
Ne i d i urn
a
hur gari ca
luneburgens is
veneta
tzsch ia
tzsch ia
t zsch ia
tzsch ia
tzsch ia
tzsch ia
tzsch i a
tzsch i a
tzsch i a
t z s c h j a
tzsch ia
tzsch ia
tzsch i a
tzsch ia
tzsch ia
N itzsch i a
N i tzsch ia
Ni tzsch ia
Ni tzschia
N i tzsch i a
N i tzsch i a
italica subsp. subarctica
sp.
ac ceptata
angI i ca
ca p itata
ca pi tata v •
capitata v .
c i nc ta
co cc one if o rm i s
cr yptocepha I a
cryp toceph a I a v
ex i gua
ex i gua v. capitata
Ianc eoIata
me n iscuI us
menisculus v. upsaiiensis
minima
pseudoscut if ormis
pupu I a
raai osa v. tene 11 a
salinarcrr v. intermedia
seminulcides
se.tii nulum
sp .
st roenr i i
term inata
tr i punctata
v i r i duI a v. ros teIt ata
v i tabunda
zanonI
ff ine
ac i cuIar i oi des
ac i cuIar1s
ac i cuIar i s?
acuta
amph ibia
angustata
angustata v. acuta
ap i cu I ata
ar chba Idi i
c I o s t e r i u m
conf i n I s
d i ss i pata
d i s s ipata v • med ia
f ont i co la
1r ustuI urn
gancershe im i ens i s
grac j I is
hantzsch i ana
I nconsp ic ua
intermedia
kue tz irig iana
0. Mull.
Hust .
Ra I f s
Ehr •
(Grun.) Ross
(Grun.) Patr.
(E h r » ) Ra I f s
Greg*
Kutz .
(Kutz.) Rabh.
Greg, ex Grun.
Patr •
(Ag.) Kutz.
Schurr.
(Grun.) Grun.
Gr un •
Hust.
KutZ •
(Breb.) CI. £ Poll.
(Grun.) CI.
Hust.
Gr un.
Hu st.
Hu St.
IQ.F.Mu I I . ) Bo r y
(Kutz.) CI•
Hust .
Hu 5 t »
Pf i tz.
Arch, non Hust.
(Kutz.) W. Sm.
(Kutz.) W. Sm.
Hantz. ex CI. £ Grun
Gr un •
(h• Sm*) Grun.
Gr un •
(Greb.) Grun.
L«-B •
(Ehr.) k. Sm.
Hust.
(Kutz.) Grun.
(Hantz.) Grun.
Grun •
(Kutz.) Grun.
Krasske
Hantz.
Rabh •
Gr un •
Hant z•
Hi Ise
-------
236
SPECIES LIST - LAKE ERIE PHY70PLANK TUN (1983)
DIV TAXON AUTHORITY
isAC N i tzs ch i a
N i tz schi a
N i tzschi a
N j tzschia
N i tzschia
N i tzschia
N i tzsch i a
N i tzsch i a
N i tzschia
Ni tzschia
Ni tzschia
N i tzschia
N i tzschia
N i tzsch ia
Ni tzschia
N itzschia
N i tzschia
N i tzsch i a
N i tzschia
Ni tzschia
Ni tzschia
N itzschia
N i t zsch i a
N i tzsch i a
Rhizosoienia
Rh i zosoI en ia
Rh i zoso i en ia
Kuetz ing i oi des ?
lauerburgiana
I i near i s
pa I ea
pa I ea v.
pa I ea v.
pa Ieacea
pum i la
pur a
pus iI I a
recta
r omana
roste i lata
soc i ab i I i s
sp.
spiCLlcides
subac i cuIar is
sub I i near i s
tenuis
tr op i ca
deb iI is
tenu i rostr i s
tr yb I
t r yb I
tr yb I
tr yb I
i one I I a
i one I I a
i one I I a
i one I I a
er i ens is
I ens i s eta
sp.
v . deb iI j s
v. v i c tor i ae
v. v i c tor i ae ?
alpinus - auxospore
aIp i nus ?
b inderanus
hant zsch i t
m inu tus
minutus - auxospore
n Iagarae
- auxospore
v. magni f ica
Skeletonema pet art os
Staurone j s kr i egerI
Stephanodiscus alpinus
Stephanod i scus
Stephanod i scus
Stephanooi scus
Stephanod i scus
Stephanod i scus
Stephanod i scus
Stephanod iscus
Stephanoai scus
Stephanodi scus
Stephanod i scus
Stephanod i scu s
Stephanod i scus
Stephanodiscus
Stephanodi scus
S tephanod iscus
Stephanod i scus
Stephanod iscus
S tephanod i scus
Surirella birostrata
Sur i re I I a ovata
Surirella ovata v* pinnata
Surirella ovata v» satina
n iagarae
n iagarae
sp.
sp.
sp.
sp.
sp.
#03
#04
#07
-auxospore
tenu i s
tenu is v. #01
tenu is v. #02
tenu i s ?
Hus t .
W . S IF •
(Kutz.) W. Sm.
(Kutz. ) Grun.
Gr un .
Grun.
Hust.
Hust.
(Kutz.) Grun. em. 1.-6.
Hantz.
Grun.
Hus t.
Hust.
Hus t.
Hus t.
Hust.
W . S rr •
Hust.
(Arnott) A. Mayer
Grun.
Gr un.
H • L . Sm.
Zach.
(Weber) Hasle £ Evens.
Patr.
Hust»
Hust.
(Kutz.) Kr ieg.
Grun.
Gr un *
Ehr •
Fr i eke
Hust.
Hust.
Hust.
Kutz.
(W. Sm.) Hust.
(In. Sm.) Hust.
-------
237
SPECIES LIST - LAKE ERIE PHYTQPLANKTON (1983)
UIV TAXON AUTHORITY
faAC Sur i r e fI a sp•
Surirella turgida
W. Sm.
Synedra acus?
KutZ.
Synedra amphicepha1 a v. austrica
(Grun.)
Hus t.
Synedra de1icatissima
W. Sm.
Synedra de1icatissima v. angustissima
Grun •
Synedra fit iformis
Grun.
Synedra filiforrris v. e x»lis
A. CI.
Synedra rr i ni scut a
Grun.
Syned ra par as i t i ca
W. Sm.
Synedra ulna v. iongissima
(W . Sm •
) Br un
Tabellaria fenestrata
Kutz.
Tabellaria ferestrata v. genicuiata
A. C 1.
Tabellaria flocculosa
(Roth)
Kutz.
Tabellaria flocculosa v. linearis
Koppen
Tabellaria sp*
Tha 1 assiosira fluviatilis
Hust.
CAT Vacuo Iari a sp.
IHL Actinastrum gracilimum
Ankistrodesmus sp.
Ankyra judayi
Carteria sp.
Carteria sp. -cvoid
Car ter i a sp. -spher e
Ch I amydocapsa planktonica
Ch I amydocap sa
Ch I amydomonas
Ch |amydomonas
Ch iamydomonas
Chlorogon ium
sp •
sp.
sp • - ovoi d
sp. - sphere
ir i n i mum
Ch I orogcn(urn sp.
Closterium aciculare
CIo sterium
C I o ster i um
Coelastrum
Coelastrum
Coelast rum
Co smar i um
par vuIum
sp *
carrbr i cum
m i cropor um
sp.
sp.
Crucigenia irregularis
Crucigenia quadrata
Crucigenia rectangu larIs
Crucigenia tetrapedia
Dictyosphaeriurn ehr enber g ianurn
Dictyosphaerium pulchellum
EJakatothrix gelatinosa
E I akato th r i x viridis
Eudor ina e tegars
France ia ova Ii s
Go Ienk i n ia r ad i ata
6r een F J lament
G.M • Smith
(G.M, Sm.) Fott
(W. C G.S. West) Fott
P iayf.
T. West
Nag*
Ar ch»
Nag. in A. Braun
M i I I e
Mor r en
A, Braun
(Kirch.) id • £ G.S* West
Nag.
Wood •
Wi I le
(Snow) Printz
Ehr •
(France) Lemm.
(Chod.) Hi Ile
-------
238
SPECIES LIST - LAKE ERIE PHYTOPLANKTON (1983)
DIV TAXON AUTHORITY
#04
- ac i cuIar
- bac iI I iform
- t i c e I I s
- fus if orm b i ce I Is
- ova t
- ovoid
- sphere
CHL Green coccoid
Gr een cocco i d
Green coccoid
Green cocco i d
Green coccoid
Green coccoid
Green coccoid
Green coccoid
Green flagellate - sphere
KirchnerieI I a contorta
K i rchneri eI I a obesa
Lagerheiinia balatonica
c iI i ata
genevensi s
i ong » seta v. major
quaor i s eta
sp.
s ubsaIsa
. •}
La ger he i rn i a
Lagerheimia
Lagerhe imia
Lagerheirria
Lagerhe i rr i a
Ljgerheimia
Lobomonas sp
Micractinium pus ilium
M onora ph i d i urr, contortum
Mono ra ph i d i um
Monoraph id i um
Monoraph id ium
Mougeo t i a sp.
Nephrocytium Agarahianum
Nephrocytium limneticum
Nephrocytium limneticum?
Oedogoniuni sp.
griff itfci i
i r regu I are
it i r ut um
Docys t i s
Oocyst i s
Oocyst i s
Oocyst Is
Oocyst i s
Oocyst» s
Oocyst i s
Oocyst i s
0 o c y s t i s
OocystIs
Oocyst j s
Oocyst Is
Pandor ina
*1
sp.
sp .
sp. ?
borge I
crassa
eI I»pt i ca
lacustr is
mar sen i i
par va
pus i I la
so Ii tar ia
submarina
mo r urr ?
v. minor
Paradoxia multiseta
Pediastrum boryanum
Pediastrum duplex v
Pediastrum duplex v
Pediastrum s i nr> p t e x
Pediastrum s imp Jex
Pediastrum sp.
Scenedesmus abindans
. clathratum
• ret 1cuIatum
v* duodenar i um
Scenedesmus
Scenedesmus
acim inatus
arcuatu s
(Schmid.) Boh Im
(W. West) Schmi dIe
(Scherff. in KoI) Hind.
(Lagerh.) Choa.
(Chod.) Chod.
G.M. Sm .
(Lemm.) G.M. Sm.
Lemm •
Fr esen i us
(Thur.) Kom.-Legn.
(Berkel.) Kom.-Legn.
(G.M. Sm.) Kom.-Legn.
(Nag.) Kom.-Legn,
Nag.
(G.M. Sm.) G.M. Sm*
(G.M. Sm.) G.M. Sm.
Snow
Wittr. in Wittr. £ Nord»
W. West
Chod.
Lemm.
West I West
Hansg.
Wittr. in Wittr. £ Nor d»
Lage rh.
(MueI I.) Bory
Sw i r .
(Turp«) Menegh.
(A. Braun) Lagerh.
Lagerh.
(Meyen) Lemm.
(B a iI.) R a b h.
(Kirch.) Chod.
(Lagerh.) Chod.
Lemm •
-------
239
SPECIES LIST - LAKE ERIE PHYTOPLANKTON (1983)
L)IV TAXON AUTHORITY
CHL
S cenede smus
Scenedesmus
Scenedestr.us
Scenedesmus
Scenedesmus
Scenedesmus
Sceneaesmus
Sceneoesnrus
Scenede srrus
Scenedesmus
Scenedesmus
Scenedesmus
Schro eder i a
a r iratus
b i cauda tu s
ca r i rat us
dent i cu latus
eccrn is
intermedius
i nterrre d j us v
quadr icauda
s ecu r if or mi s
sp.
sp i nosus
sp i nosu s?
b i cauda tus
s e t i ger a
SphaereIIocystis lateralis
Sphaerellopsis sp*
Sphaerocystis schroeteri
Staurastrum paradoxum
Staurastrum sp.
St i chococcus sp.
Tetraedron caudatum
m i n i mum
muti cum
r eguI are v
I a custr i s
he teraca nt hum
staurogeniaeforme
pIank ton ica
Tetraedron
Tetraedron
Tetraedron
Tetraspora
Tetrastrum
Tetrastrum
T reubari a
incus
T r euba r i a
Tr eubar i a
se t i gera
sp.
CHR Bitrichia chodatii
Chrysolykos planktonicus
Chrysolykos sk ljae
ChrysosphaereI I a longispina
Dinobryon acuirinatum
Dinobryon bavaricum
Dinobryon cylinaricum
Dinobryon divergens
Dinobryon sertularia
Dinobryon sociale v.
Dinobryon sp.
Dinobryon stokesii v
D i nobr yor ut r i cuI us
Haptophyte sp.
Kephyrion cupuliformae
Kephyrion sp. #1 -Pseudokephyrion
Kephyr ion sp. #2
Kephyrion sp. #3
Ma I Iomonas s p.
Ochromonas sp.
Ochromonas sp. - ovoid
Paraphysomonas sp.?
airer icanum
. epipIanktonicum
v . tabe11ar iae
entz I i
(Chod.) G.M. Sm.
(Hansg.) Chod.
(Lemm.) Chod.
Lage rh.
(RaIf s ) Chod.
Chod.
Ho r t ob .
(Turp* ) Breb.
P I ayf.
Chod *
Choo.
(Schroed.) Lemm.
Fott L Novak.
Chod.
Meyen
(Corda) Hansg.
(A. Braun) Hansg.
(A. Braun) Hansg.
Te iIung
Lemm.
(Nordst.) Chod.
(Schroed.) Lemm.
(G.M. Sir..) Korch.
(Arch.) G.M. Sm.
(Rev.) Chod.
Mack •
(Naut«. ) Bour r .
Laut. em. Mich.
Rutt.
Imhof
Imhof
Imhof
Ehr •
(Brunnth.) Bachm.
Sku ja
Lemm.
Conr .
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240
SPECIES LIST - LAKE ERIE PHY TOP LANKTON ( 1983)
DIV TAXON AUTHORITY
CHR
COL
CRY
CYA
Pseudokephyr i cn rrillerense
Pseudokephyrion sp. #1
Pseudotetraedron neglectum
Unidentified coccoids
Unidentified flagellate
Unidentified loricate - ovoid
Unidentified loricate - sphere
Bicoeca campanulata
Bicoeca crystal I ina
Bicoeca sp.
Bicoeca sp. 0 01
B i coeca sp. #04
Bicoeca sp. UC5
Bicoeca tubiforrris
Codonos i ga sp.
Colorless flagellates
Colorless flagellates
Monos i ga ovat2
Salpingoeca amphorae
Sa I p I ngoeca gracilis
SteIexmonas dichotoma
Stylotheca aurea
- colonial
Chr oomona s
Chr oomona s
C r yp t omona s
Cr yptomonas
Cr yptomonas
Cr yptomonas
Crypt omona s
Cr yptomonas
Crypto rronas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Rhodomonas
Rhodomonas
Rhodomonas
a c 11 a
nor stedt i i
- cyst
ca coata
curvata
curvata ?
er csa
ercsa v. reflexa
irarsson i i
ma r s son i i v.?
o vata
phaseoI us
pyrenoIaifer a
reflexa
rcstrat iformis
r ost rat iformis?
sp.
lens
m i nuta
mi nuta
v* nannop I anktica
Agmenellum quadrup I icaturn
Anabaena sp*
Anabaena spircides
Anacyst i s marina
Anacystis montana v. minor
Anacyst i s therrra I is
Anacystis thernralis f. major
N i ch •
Pasch.
(Lack.) Bourr. em. Skuja
Sku ja
Skuja
Kent
Kent
Clark
Lack •
( Bachni. ) Bo I och .
U t e r m.
Hans g.
Schi I I .
Ehr .
Ehr .
Ehr.
Mar s s•
Skuja
Skuja
Ehr .
Skuja
Ge i 11 •
Skuja
Skuja
Skuja
Pasch* I Rutt.
Skuja
Skuja
(Menegh*) Br eb.
K ieb*
(Hansg• ) Or. L Daily
Or• £. Da i I y
(Menegh •) Dr. € Da I | y
(Lager h •) Or• fc Da i I y
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241
SPECIES LIST - LAKE ERIE PHYTOPLANK TON (1983)
LiIV TAXON AUTHORITY
CYA
cUG
PYR
Aphanizomenon flos-aquae
Coccochloris elabans
Coccochloris peniocystis
C oe I ospha er i urn flub i urn
CoeIosphaeriurn naegelianum
Gorrphosphae r i a lacustris
Merismopedia tenuissima
Osc iI Iator ia
Osc iI Iato r i a
0 sc iI Iato r i a
OsciI Iatoria
Eug Iena sp.
T rachelomonas
I i mnet i ca
subbrevi s
tenuis
tenuis?
sp.
Amph i d i n i um sp *
Ceratium hiruncinella
Ceratium hirunflineI I a - cyst
Gymnod in i um sp •
Gymnodin ium sp* #2
Gymnodinium sp* #3
Peridinium acicuIiferum
Peridinium acicu I iferum?
Peridinium i nccnsp i cuurr
P er i d i n i um sp •
(L.) Ralfs
Dr• £ Da i I y
(Kutz* ) Or• L Da i I y
Grun. in Rabh.
Unge r
Chod •
Lemm •
Lemm .
Schm i d.
C.A. Ag.
C • A • A g •
(O.F*MuII*) Schrank
(D.F*MuII*) Schrank
Lemm *
Lemm*
Lemm •
UNI Unidentified flagellate #01
Unidentified flagellate - ovoid
Unidentified flagellate - spherical
-------
242
SPECIES LIST - LAKE HURON PHYTOPLANKTGN (1983)
L) I V TAXON
AUTHORITY
BAC Achnanthes
Achnanthes
Achnanthes
Achnanthes
Ac hnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Ac hnanthes
Achnanthes
Achnanthes
Ac hnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Ac hnanthes
Achnanthes
Achnanthes
Achnanthes
Amphipleura
af f i n i s
biasolettiana
brevipes v. intermedia
c I e v e i
cI eve i v. rostrata
consp i cua?
0 e tha
e x i gua
exigua v. heterovalva
fIexe I la
ha cck i an a
Ianc eolata
Ianceola ta v<
lapponica v.
Iaterost rata
1 i near i s
linearis f o.
irarginulata
m i c r oc ep ha I a
minutissima
s p •
pel Iuc i aa
i duoia
n inckei
cu r ta
Amphora coffeiformis
Amphora i nar i ens i s
Amphora oval is
Amphora oval is v. pediculius
Amphora perpus ilia
Amphora sp.
Anomoeone is v i trea
Asterionella forrrosa
Aster i one I I a forrrosa
Ca I one is bac i I I urn
Cocconeis diminuta
Cocconeis disculis
Cocconeis placentula v. euglypta
Cocconeis placentula v. lineata
CycIostephanos dubius
v. g rac iI Ii ma
CycIotel
CycIoteI
Cy cIot eI
CycIoteI
C y c I o t e I
CycIo t eI
CycIot eI
Cy cIot eI
CycIoteI
Cyc I oteI
Cyc I oteI
CycIoteI
CycIoteI
CycIoteI
C y c I o t e I
a ant i qua?
a catenata
a comensis
a corrensis - auxospore
a conrensis v. 1
a correns is v. 2
a c o it t a
a corrta - auxospore
a corrta v. HZ
a corrta v. oligactis
a c r y p t i ca
a kuetz ingiana
a kuetz ing iana v.
a kuetzingiana v.
a kuetzingiana v.
Gr un •
(Kutz*) Grun.
(Kutz *) CI*
Grun*
Hus t.
A. Mayer
Hohn t Hellerm.
Grun •
Krasske
(Kutz*) Brun*
Grun.
(Breb.) Greg.
Grun*
(Guerm. £ Mang.) Rein,
Hust •
(M. Sm.) Grun.
H.L. Sm.
Grun.
(Kutz.) Grun.
Kutz •
(Kutz.) Kutz.
(Ag.) Kutz •
K r am •
(Kutz.) Kutz.
(Kutz.) V.H. ex DeT.
(Grun.) Grun*
(Grun.) Patr. £, Re im.
Ha s s.
(Han tz.) Grun
(Grun.) CI.
Pant.
(Schum . ) CI.
(Ehr . ) CI.
(Ehr .) CI.
(Fr i eke) Round
W • S ni *
Brun.
Grun.
(Ehr • ) Kutz•
pIane tophor a
p I ane to phor a?
r ad i osa
(Ehr.) Grun.
Re i m. e t a I .
Th w.
Fr i eke
F r i c k e
Fr i eke
-------
243
SPECIES LIST - LAKE HURON PHYTUPLANKTON <1983)
DIV TAXON AUTHORITY
BAC Cyclotella
C y cIo t e I la
C y cIo t e I la
Cy c I o t eI la
Cyclotella
Cyc I ote I la
CycIote I la
CycIote I la
CycIote I la
Cyc I ote I la
menegh in iana
nr. i ch i gan iana
o c e I lata
operculata
pseuooste I I igera
sp.
sp • VI
sp • U2
sp. - auxospore
ste I I igera
ap i cuIata
Cymatopleura solea v
CymbeI I a angustata
I ae v i s
micrccepha la
m i n u t a
minuta v. silesiaca
navicul iformis
sp.
t ri a ncuI urn
s p •
CymbeI I a
C y mbeI la
CymbeI la
Cymbe I la
Cymbe I la
CymbeI la
CymbeI la
Dent i cu la
s V i
c r as su I a
Dent i cula tenu
D i atoma tenue
Diatoma tenue v. eloncaturr,
D i pI one is eI I i p t i ca
Diploneis obIonge I I a
Diploneis oculata
Entomone i s or nata
Kut z .
Sk v.
Pant.
(Ag.) ku tz.
Hust .
(CI. L Grun. ) V ,H.
(to. Sm . ) Ra 11 s
( to« Siti • ) CI.
Naeg • ex Kutz•
Grun.
Hi I se
(BIe i sch ) Re i m.
Auer sm.
(thr .) CI.
(Nag.) W . £ G. S. West.
Ag.
Ly n g b.
(Kutz . ) CI*
(Naeg.ex Kutz.) Ross
(Breb. ) CI•
(J *W * Ba i I .) Re i m.
Eunot
a praerupta
Ehr .
F r ag i
aria
brev i striata
Grun.
F r ag 1
aria
brevistriata v. subcapitata
Gr un •
F r ag 1
aria
capuc ina
Desm .
Fr ag 1
aria
capucina v. mesolepta
(Rabh. )
Grun *
Fr ag i
aria
co ns tr ue ns
(Ehr *)
Grun*
Frag 1
aria
construens v. minuta
Temp. £
Per .
Fr ag i
aria
construens v. pumila
Grun.
Fr ag 1
aria
construens v. subsalina
Hus t •
Fragi
aria
construens v. venter
(Ehr .)
Grun.
Frag i
aria
crotcnensi s
Ki tton
Frag 1
aria
i nterrred ia v. f al lax
(Grun.)
Stoer m.
Fragl
aria
1 e pto sta ur on
(Ehr.)
Hust *
Fragi
aria
leptostauron v. dubia
(Grun.)
Hust.
Fragl
aria
p i nnata
Ehr •
Fragl
aria
pinnata v. intercedens
(Grun*)
Hust.
Fragl
aria
pinnata v. lancettula
(Schum.
) Hust.
Fragl
aria
sp.
Fragl
aria
vaucher i ae
(Kutz*)
Peters *
Gomphonema
angustatum
(Kutz.)
Rabh *
Gomphoneira
d1chotomum
Kutz *
Gomphonerra
grac i le
Ehr* em
* V.H*
Gomphonema
o 1 1 vaceuit
(Lyngb*
) Kutz*
Gomphonema
par vu lum
Kutz *
Gomphonema
sp •
-------
244
SPECIES LIST - LAKE HURON PHYTOPLANKTON (1983)
DIV 7AXON
AUTHOkITY
bAC Hantzschia amphioxys
Melosira d i s tans
Me Ios i ra d i stans?
Melosira granu lata
Melosira granu lata v
Me I os i ra i sI and i ca
Melosira itaIica subsp.
Melosira sp.
angust iss ima
subarct i ca
Na v
cu
a
acceptata
Na v
c u
a
atomus
Na v
cu
a
cap i tata v.
1unebur gens
Na v
c u
a
c i nc ta
Na v
c u
a
conf ervacea
Na v
cu
a
cont erta v.
b icep s
Na v
cu
a
cryptocepha
la v. veneta
Na v
c u
a
go tt1 and i ca
Na v
c u
a
medi ccr i s
Na v
c u
a
minima
Na v
c u
a
mur a 1 i s
Na v
c u
a
a. u r a 1 is?
Na v
c u
a
mut i ca
Na v
c u
a
p e r p u s i1 la
Na v
cu
a
r ad i osa
Na v
cu
a
rad i osa v.
par va
Na v
cu
a
raoiosa v.
tene 1 1 a
Na v
c u
a
sem i nu1um
Na v
c u
a
s i m i lis?
Na v
c u
a
sp.
Na v
cu
a
sp. *16
Na v
c u
a
sp. #16
Na v
cu
a
submtra1 is
Na v
c u
a
subt i 1 i ss i ma
Na v
c u
a
tantu la
Na v
cu
a
v i r i du1 a v •
avenacea
Na v
c u
a
v i r i cu1 a v .
roste1 Iata?
Nitzschia acicuIarioifles
Nitzschia ac i cu I ar i s
Nitzschia acuta
Nitzschia amph i D i a
Nitzschia angustata
Nitzschia angustata v. acuta
Nitzschia confinis
Nitzschia diss) pata
Nitzschia f ont i cola
Nitzschia frustulum
Nitzschia frustulum v. perpusilla
N i tzsch ia gracilis
Nitzschia kuetzingiana
Nitzschia I auerburgiana
Nitzschia palea
Nitzschia paleacea
Nitzschia pura
(Ehr . )
Grun,
(Ehr . )
Kutz .
(Ehr .)
Kutz.
(Ehr .)
Ra 1 f s
0. Mul
1 .
0. Mul
1 .
0. Mul
1 .
Hust .
(Kutz.) Grun.
(Grun.) Patr.
(Ehr .) RaIf s
Kutz .
(Arn.) V.H.
(Kutz* ) Rabh,
Grun*
Krasske
Grun.
Grun.
Grun.
Kutz •
(Kutz.) Grun.
Kutz.
Ma I lace
IBreb.) CI. L Moll
Gr un •
Krasske
Hust.
C I .
Hu s t •
(Breb.) V.H.
(Kutz.) CI.
Arch, non Hust.
(Kutz.) W. Sm.
Hantz. ex CI. £
Grun.
(M. Sm.) Grun.
Grun.
Hust.
(Kutz.) Grun.
Grun.
(Kutz. ) Grun•
(Rabh.) Grun.
Hantz.
Hi I se
Hust.
(Kutz.) W. Sm.
Grun.
Hust.
Grun.
-------
245
SPECIES LIST - LAKE HURON PHYTOPLANKTON <1983)
L)IV TAXON AUTHORITY
bAC
N i tzsch i a
N i tzsch ia
N i tz sch i a
N i tz sch i a
N i tzsch ia
N i tz s ch i a
N i tz sc h i a
N i tzsch i a
Opephora
pus iI la
recta
r omana
r oste I lata
sp •
sub I inear t s
subrostrata
tenuis
irar ty i
Pinnularia micrcstauron
Rhizosolenia eriensis
Rh i zosoI en i a sp.
Stephanodiscus alpinus
S tephanodi sc us
S tephanodi sc us
Stephanod i scus
Stephanod i scus
Stephanod i scus
StephanodIsc us
S tep hano ci sc us
Stephanod i scus
Stephanod i scus
Stephanodi scus
S tephanodi sc us
Stephanod i scus
Stephanod i scus
Stephanod i scus
Stephanod i scus
S te phano d i sc us
Stephanod i scus
alpinus - auxospore
aIp i nus?
binder anus
binder anus ?
hant zs ch i i
in i nu tus
n iagar ae
niagarae - auxospore
sp.
sp. #03
sp* #05
sp* -auxospore
tenu t s
tenu is v* #01
tenu is v• MQZ
tenu i s ?
t ran si I van i cus
Surirella ovata
Surirella ovata v. salina
Synedra amphicephala v. austrica
eye Iopum
delicatissima
deIica11ssI ma v. angustisslma
f ame i I i ca?
f i I if crm i s
f i I i f crm i s v. ex i I i s
m i n i scula
nana
par as i t i ca
rad i ans
Synedra
Synedra
Synedra
Synedra
Synedra
Synedra
Synedra
Synedra
Synedra
Synedra
Synedr a
Synedra
Synedra
Synedra
Synedra
Synedra
Tabe Maria
TabeIlar ia
TabeI Iar i a
rumpens
rumpens
sp.
ulna v•
uIna v •
ulna v.
v. f ragI Iar io ides
cha seana
dan i ca
Iong i ss ima
(Kutz*) Grun. em* L.-B,
Hantz•
Grun.
Hust •
Hust.
Hust.
W. Sir.
He rIb.
(Ehr*) CI .
H.L. Sm.
Hu st.
Hust .
(Kutz.) KrI eg.
(Kutz* ) Kr ieg.
Gr un.
Gr un.
Ehr.
f erestrata
fenestra ta
f I occulosa
v* geniculata
Hust *
Hust .
Pant.
Kutz.
(w. Sm.) Hust.
(Grun.) Hust.
Br ut schy
W . S ID .
Gr un *
Kutz *
Gr un.
A. CI.
Gr un.
Me ister
W • S in *
Kutz.
KutZ *
Gr un.
Thomas
(Kutz.) V.H.
(m. Sm*) Brun*
Kutz.
A. CI.
(Roth) Kutz.
-------
246
SPECIES LIST - LAKE HURON PHYTOPLANKTON (1983)
l)IV TAXON AUTHORITY
mi rab iI is
BAC Tab eI I a r i a flocculosa v. linearis
Tabe Maria sp .
ThaI ass i r os i ra sp*
CAT Vacuolar ia sp.
Vacuolar i a sp*?
CHL Ank i strodesmus
Ank i strodesmus
Ank i strodesmus
Ank i strodesmus
Ank i strodesmus
Ank i strodesmus
Ank i strodesmus
Botryococcus Braunii
Ch I amydocapsa bacillus
Ch Iamydocapsa
Chlamydocapsa
Ch I amydocap sa
Ch I amydomona s
Ch I amydomonas
Ch I amydomonas
Coelastrum microporum
Co smar i urr sp .
Cosmar ium sp. #1
Crucigenia irregularis
Crucigenia quadrata
Crucigenia rectanguiaris
D i ctyosphaer i uir. pulchellum
EchinosphaereI I a limnetica
Elakatothrix gelatinosa
E I aka to th r i x viridis
Eudor i na e I egars
France ia ova I i s
G I oeocys t i s sp. #3
Go I enk i n ia rao iata
Green coccoid #02
Koppen
faIcatus
fa Icatus v.
ge I i factum
sp* #01
sp* #02
spiral is
st i p i tatu s?
pIank ton i ca
sp*
s p * ?
sp*
sp • — ovoid
sp* - sphere
Green
Green
Green
Green
Green
Green
Green
Green
coccoid
coccoid
coccoid
coccoid
coccoid
coccoid
cocco i d
coccoid
a
#03
#04
- ac i cuIar
- bac i I I if orm
- fci c e I I s
- fusiform
- ova I
- sphere
co nto r t a
K i r chner i e
Lager he i m i a c iIi ata
Mi cract in ium pus ilium
Monoraphidiurn contortum
Mono ra ph i d i urn convolutum
Monoraph i d ium irinutum
Monoraphidium saxatile
I Co r da ) RaIf s
(West € West) G.S* West
(Chod.) Bourr*
(Turner ) Lemm.
(Chod.) Kom.-Legn*
Kutz *
( Te i I *) Fott
(W* L G.S. I*est) Fott
Nag* in A * Braun
W i I I e
Morren
A* Braun
Wood •
G.M. Sm *
W i I I e
(Snow ) Pr i ntz
Ehr *
(France) Lemm*
(Chod.) WiIle
( Schrr id.) Boh I m
(Lagerh*) Chod*
Fr esen i us
(Thur.) Kom.-Legn.
(Corda) Kom.-Legn.
(Nag.) Kom.-Legn.
Kom.-Legn.
-------
247
SPECIES LIST - LAKE HUkON PHYTOPLANKTON (1983)
DIV TAXON AUTHORITY
CHL
CHR
Monoraphid ium setiformae
Mougeotia sp.
Oocy st i s sp .
Oocy st i s sp . (/I
Oo cyst i s Bo rge i
Oocystis crassa
Oocyst i s Iacustris
Oocystis ma r s cn i i
Oocyst is parva
Oocyst i s pus ilia
Oocystis solitaria
Pyramidomonas sp.
Scenedesmus abindans
Scenedesrrus
Scenedesrrus
Scenedesrrus
Scenedesmus
Seen edesmus
Scenedesrrus
Scenedesrrus
Scenedesrrus
dent i cu la tus
eccrn i s
s ecu r if or mi s
secur if orrris?
ser ratus
sp.
subsp i catus
veIi tar is
Sphaere I I ocystis lateralis
Sphaerocyst i s schroeteri
St i chococcus sp*
Synechococcus sp*
TetrachIoreI I a alternans
Tetraedron minimum
Treubaria planktonica
Treubaria planktonica?
Treubaria setigera
B i tr i ch i a chodati i
Chrysolykos planktonicus
Chrysolykos sktjae
ChrysoIykos sp*
Chrysosphaere11 a longispina
Dinobryon - statospore
acurr, i na turn
Dinobryon
D i nobryon
D i nobr yon
D i nobr yon
D i nobryon
0 i nobr yon
D i nobr yon
D i nobr yon
0 i nobryon
D i nobryor
0 i nobryon
0 i nobryon
D i nobr yon
0 i nobryor
Haptophyte
bavar i cum
bor ge i
cy I i ndr ic um
cyIi ndr ic um
d i vergens
divergens -
eurystoma
ser tUar i a
sertularia v. protuberans
soc iaIe
soc i a Ie v•
stokes i i v
ut r i cuI us
sp.
v. a Ip i num
statospor es
arrer i canum
ep i plankton i cum
• tabeI Iar iae
(Nyg.) Kom.-Legn.
Snow
Wittr. in Wittr. £ Nord.
Chod.
Lemm •
West L West
Hansg.
Wittr. in Wittr. & Nord.
(Kirch.) Chod.
Lagerh.
(RaIfs) Chod*
P I ay f.
P I ay f .
(Corda) Bohlm
Chod.
Kom *
Pott £ Novak.
Chod.
(G *M. Smith) Kors.
(A. Braun) Hansg*
(G.M. Sm*) Korch*
(G.M. Sm.) Korch.
(Arch.) G.M. Sm.
(Rev.) Chod*
Mack *
(Nauw.) Bourr.
Laut. em. Nich.
Rutt.
Imhof
Lemm.
Imhof
(Imhof) Bachm.
Imhof
(Stokes) Lemm*
Ehr *
(Lemm. ) Kr ieg.
Ehr *
(Brunnth*) Bachm*
Sku ja
Lemm*
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248
SPECIES LIST - LAKE HURON PHYTUPLANKTON (1983)
UIV TAXON AUTHORITY
CHR
COL
CRY
Kephyr i on
Kephyr i on
Kephyr i on
Kephyr i on
Kephyr i on
Hal Iomonas
Mallomo na s s p •
Ma I Iomo na s s p •
Oc hr omona s sp •
Ochromonas sp.
Ochromonas sp.
Paraphysomonas
Paraphysomonas
Pseudokephry i on
Pseudokephyr i on
P seudokephyr i on
Pseudokephyr i on
Pseudokephyr i on
Unidentified
Un i dent i f i ed
cupul i for ma e
sp. U1 -Pseudokephyrion
sp . Ml
sp . #3
sp i ra I e
sp.
*1
#3
en tz ii
- ovoid
- sphere
sp.
sp. ?
en t z i i
con i c urr
I a t urn
rr i I I e rense
sp. #1
cocco ias
I or i ca te -
ovoid
Unidentified loricate - sphere
Bicoeca campanulata
B i coeca crystaI I ina
Bicoeca mitra v. suecica
Bicoeca socialis
Bicoeca sp»
Bicoeca sp. #04
Bicoeca tub i f or m i s
Colorless flagellates
Mono s i ga ovata
Monosigna oval is
Salpingoeca amphorae
Sa I p i ngoeca gracilis
Stylotheca aurea
Chroomonas
Chr oomona s
Ch r oomona s
Cr yptomonas
Cryptomonas
Cr yptomona s
Cryptomonas
Cryptomonas
Cr yptomonas
Cr yptomonas
Cryptomonas
Cryptomonas
Cryptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
acuta
cacdata
norstedti i
- cyst
brev i s
caudata
er csa
er csa v. refIe xa
rrarsson i i
obovata ?
ovata
parapyr eno i d ifera
phaseoI us
phaseoI us ?
pus i I la
pyreno i ci fer a
Conr .
(Lack . ) Conr•
Conr .
(Sch iI I•) Schum.
(Schill.) Schum.
N i ch *
(Lack.) Bourr. em. Skuja
Sku ja
Skuja
Laut er b.
Skuja
Kent
Kent
Kent
Clark
(Bachm.) Boloch.
Uterm.
Ge i t.
Hans g.
Sch ill.
Schi I I.
Ehr .
Mars s.
Skuja
Skuja
Ehr.
Skuja
Skuja
Skuja
Bachm.
Ge it I.
-------
249
SPECIES LIST - LAKE HURON PHYTOPLANKTON (1963)
DIV TAXON AUTHORITY
CRY Cryptomonas
Cr yptomonas
Crypt omona s
Cr yptomonas
Cr yptomonas
Rhodomonas
Rhodomonas lens
Rhodomonas minuta
Rhodomonas minuta v.
Unidentified coccoid
r e fIexa
rostrat ifcrmis
sp.
tenuis
tetrapyrenoidiosa?
I acus tr is
nannoplankti ca
Sku ja
Sku ja
Pasch.
Sku ja
Pasch.
Pas ch*
Sku ja
Sku ja
£ Rutt•
£ Rutt.
CYA Anabaena circinalis
Anabaena sp*
Anacystis marina
Anacystis montana v. minor
Anacysti s thernra I is
Coccochloris elabans
Coccochloris peniocystis
Coe I o sphae r i urr Naeg e I ianum
Gomphosphaeria lacustris
Oscillatoria limnetica
Osc i I I ato r i a rr i n ima
Oscillatoria scbbrevis
Osc iI Iator i a tenuis
Rabenhor st
(Hansg •) Or. £ Daily
Or• £ Da i I y
(Menegh•) Or• £ Da i Iy
Dr• £ Da I I y
(Kutz•) Dr* £ Daily
Unge r
Chod*
Lemm •
G i ckIh•
Schm i o.
C • A • A g •
EUG Euglena sp*
Phacus sp*
TracheIomonas hispioa
TracheIomonas sp*
PYR Amphidinium sp*
Ceratium hlrundinella
Gymnodi n i um sp *
Gymnodinium sp* HI
Gymnodinium sp* #2
Gymnod in i um sp* #3
Gyirnodinium sp* *5
Peridinium inconspicuum
Per i d ini um sp*
Peridinium sp* 002
(Per ty) Stein em * De fI *
(O.F.MuII*) Schrank
Lemm •
UNI
Unidentified flagellate #01
Unidentified flagellate - ovoid
Unidentified flagellate - spherical
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250
SPECIES LIST - LAKE MICHIGAN PHYT0PLANKT0N (1963)
DIV TAXON AUTHORITY
bAC Achnanthes affinis
b i a so Iet t iana
c I e v e i
c I eve i v.
consp i cua
del I exa
ex i gua
e x i gua v .
fIexe I la
ha tck i an a
Ianceola ta
lanceolata v
lapponica v •
Iapponica v.
I i near Is
I i n ea r i s f o•
it) i nut i ss ima
oestr up j i v •
sp.
such I and t i i
Actinocyclus norrranii f
Amphipleura pellucida
Amphora oval is
cvalis v. aff ins
oval is v» pediculius
per pus iI la
sp.
t humen sus
Anomoeoneis vitrea
Asterionella forrrosa
CaI one is sp*
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnantnes
Achnanthe s
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Achnanthes
Amphora
Amphora
Amphora
Amphora
Amphor a
r os tr ata
con str i eta
• dub i a
n i ncke i
n i ncke i ?
cu r ta
I anceolata
suDsaIsa
Coc c on e
Coccone i s
Cocconei s
d i m i nuta
di scuILS
pi acentula
v. euglypta
Gr un.
(Kutz.) Grun.
Gr un .
Hus t •
A. Mayer
Reim. in Patr. £. Reim.
Grun •
(Grun.) Hust.
(Kutz.) Brun.
Grun.
(breb.) Greg.
Grun.
(Guerm. I Mang.) Reim.
(Guerm. L Mang.) Reim.
(ri. Sm.) Grun.
H. L . S (it •
Kutz.
Hust .
Hust.
(JuhI.-Dannf. ) Hust.
(Kutz.) Kutz .
(Kutz.) Kutz .
(Kutz.) V.H. ex DeT.
(Kutz.) V.H. ex DeT.
(Grun.) Grun.
(Mayer) A. CI.
(Grun.) Patr. £ Reim.
Hass.
Pant.
(Schum.) CI.
(Ehr .) CI.
Cocc one
s
placertula v. lineata
(Ehr .) CI.
Coccone
s
thumensis
A. Mayer
Cyc 1 ote
1 a
ant i qua
M. Sm.
Cyc 1 ote
1 a
ant i qua?
W. Sir.
Cyc 1 ote
1 a
atorrus
Pant.
Cyc1ot e
1 a
comensi s
Gr un.
Cyc 1 ote
1 a
corrensis - auxospore
Cyc 1 ote
1 a
conrensis v. 1
Cy c 1 o t e
1 a
coirensis v. 2
Cyc1ot e
1 a
c o n t a
(Ehr.) Kutz.
Cy c1ot e
1 a
corrta - auxospore
Cyc1ote
1 a
coirta v. o 1 i gact is
(Ehr.) Grun.
Cyc 1 o t e
1 a
c r yp t i ca
Re i m. et a 1.
Cyc 1 ote
1 a
Kuetz i ng iana
Thw.
Cyc1ot e
1 a
menegh i n iana
Kutz.
Cyc 1 ote
1 a
m i ch i gan iana
Skv.
Cyc 1 ote
1 a
michiganiana - auxospore
Cyc1ote
1 a
oce 1 lata
Pant.
-------
251
SPECIES LIST - LAKE MICHIGAN PHYTOPLANKTON (1983)
DIV TAXON
6AC CycIotel la
CycIoteI la
C y c I o t e I la
Cyc I oteI la
CycIoteI la
CycIote I la
CycIoteI la
Cymatop I eu ra
CymatopIeu ra
operculata
operculata unipunctata
pseudosteI I i gera
sp.
sp • Ml
sp • - auxospore
ste I I i ge ra
e I I i pt i ca
so I ea
CymbeI I a c esat i i
Cymbella cistula v. gibbosa
CymbeI I a delicatula
Cymbella micrccephala
Cymbella rr. i nuta
Cymbella minuta v. silesiaca
Cymbella norvecjca
Cymbella prostrata v. auerswaldii
CymbeI I a s i nuata
Cymbella sp.
Cyrrbella trianculum
Denticula tenuis v. crassula
D iatoma tenue
Diatoma tenue v. eloncatum
D i pI one is eI I i p t i ca
0 i pI one is ocu lata
Diploneis par ma
Oiploneis sp*
E ntomone
Eunot
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
Frag
i a
lar
lar
I a r
lar
lar
iar
lar
I a r
lar
lar
lar
I a r
lar
lar
lar
lar
la r
lar
Gomph onema
Gomphonerra
Gomphoneira
Gomphonema
Gomph onema
s ornata
n c i sa
a Drev i str iata
brev i str iata
brev i str iata
capucIna
capuc i na v•
construens
constr ue ns
construe ns
co ns tr ue ns
construens v
cr otonensis
Ie ptosta ur on
p i nnata
pinnata v.
p i nnata v•
sp •
vaucher i ae
vaucheri ae
af fIne
d I chotomum
gr ac i I e
par vuI urn
sp.
v• i nfIata
v* subcapitata
meso I epta
v •
v •
v.
b i nod Is
minuta
subsaIi na
venter
intercedens
IancettuI a
v. cap! teI Iata
AUTHOKITY
(Ag.) Ku tz.
Hust •
Hu st.
(CI. £ Grun.) V.H.
(Breb. ) W .Sm.
(Breb. £ Godey) W. Sm.
(Rabh.) Grun. ex A.S.
Br un.
Kutz .
Grun.
Hi I se
( B Ie i sch ) Re irn.
Gr un •
(Rabh. ) Re i m.
Greg.
(Ehr . > CI.
(Nag.) W. £ G.S. Ixlest.
Ag.
Lyngb.
(Kutz.) CI.
(Breb.) Ci.
Ci .
(J• W» Ball.) keim.
M. Sm.
Grun.
(Pant.) Hust.
Gr un.
Desm .
(Rabh.) Grun.
(Ehr.) Grun.
(Ehr.) Grun.
Temp. £ Per.
Hust.
(Ehr.) Grun.
K i tton
(Ehr.) Hust.
Ehr •
(Grun.) Hust.
(Schum.) Hust.
(Kutz.) Peters.
(Grun.) Patr.
Kutz.
Kutz.
Ehr. em. V.H.
Kutz.
-------
252
SPECIES LIST - LAKE MICHIGAN PHYTOPLANKTON (1983)
TAXDN
AUTHORITY
Gyros i gma
sc i ctense
(Su1 1 i v
• L Worm 1 ey) C
Me 1 os i ra
arr.D i qua
(Grun. )
0. Mull.
Me 1 os i ra
d i stans
(Ehr .)
Kutz.
Me 1 os i ra
granu lata
(Ehr .)
Ra 1 f s
M e 1 o s i
r a
granulata v. angustissima
0. Mull
•
M e 1 o s i r a
i s1 and i ca
0. Mu1 1
•
Me 1os i
r a
i ta1 i ca
(Ehr . )
Kutz .
Me I o s i r a
italica suDsp. subarctica
0. Mul 1
•
Me 1 os i ra
sp *
Mer i d i on
c i r cu 1 are
(Greg. )
A g.
Na v i cu
1 a
anglica v. signata
Hus t.
Na v i c u
1 a
ang1i ca v. subsa 1 sa
(Grun.)
C 1 .
Na v i cu
1 a
cap i ta ta
Ehr .
Nav i cu
1 a
capitata v. hurgarica
(Grun.)
Ross
Na v i cu
1 a
c i nc ta
(Ehr. )
Ra 1 f s
Na v i c u
1 a
cr yptocepha 1 a
Kut z •
Nav i cu
1 a
cryptocepha 1 a v. veneta
(K ut z • )
Rabh .
Na v i cu
1 a
exigua v, capitata
Pat r .
Nav i cu
1 a
gr ac i 1 o i de s
A. Mayer
Nav i cu
1 a
gr ega r i a
Donk •
Nav i cu
1 a
i rtegra
( W. Sm •
) Ra 1 f s
Nav i cu
1 a
jaernefeldti i
Hus t •
Na v i cu
1 a
1 a cu s t ri s
Greg.
Nav i cu
1 a
1anceo lata
(Ag . ) Kutz.
Nav i cu
1 a
meni sculus v. upsaliensis
(Grun.)
Grun.
Nav i cu
1 a
m i n i ft a
Grun.
Nav i cu
1 a
pseuaore inhardt i i?
Patr .
Na v i cu
1 a
pupu1 a
Kutz.
Na v i c u
1 a
rad i osa
Kutz .
Na v i c u
1 a
raaiosa v. tenella
(br eb. )
CI. L Moll.
Nav icu
1 a
re inhar dt i i
(Grun. )
Grun.
Na v i cu
1 a
seminuloides
Hu s t.
Na v i cu
i a
seminulum
Grun.
Nav i cu
1 a
sp.
Nav i cu
1 a
tr i purctat a
(O.F.MuII.) Bory
Nav i cu
1 a
tripunctata v. schizonemoides
(Breb.
ex Grun.) V.H.
Nav i cu
1 a
tuscu 1 a
Ehr .
Nav i cu
1 a
v i r i du1 a
(Kutz. )
Ehr.
Ne i du im sp. #1
N
tzsch i a
ac i cu1ar i o ides
Ar ch.
non Hust.
N
tzsch i a
ac i cu 1 ar1s
(Kutz.
) W. Sm.
N
tzsch i a
ac u 1 a
Hant z.
ex CI. 1
N
tzsch i a
acuta
Han t z.
N
tzsch ia
amphibia
Grun.
N
tzsch i a
angustata
(M • Sm
.) Grun.
N
tzsch i a
angustata v. acuta
Grun.
N
tzsch i a
bacata
Hus t.
N
tzsch i a
cap i te11 a ta
Hus t.
N
tzsch i a
conf i n1s
Hu s t.
N
tzsch i a
conf in i s?
Hu s t.
N
tzsch i a
d i ss i pata
(Kutz.
) Grun.
Ni tzsch i a
f ont i cola
Grun.
-------
253
SPECIES LIST - LAKE MICHIGAN PHYTOPLANKTON (1983)
DIV TAXON AUTHORITY
dAC
N
tzsch ia
fr ustu 1 um
(Kutz* )
N
tzsch i a
frustulum v. minutula
N
tzsch i a
gancer she im i ens i s
Kr as ske
N
t z s c h i a
g r a c i 1 is
Hant z *
N
t z sc h i a
i mp r essa
Hust *
N
tzsch i a
k ue tz i ng i ana
H i 1 se
N
tzsch ia
1auerburg iana
Hust *
N
tzsc h i a
1i near is
W* Sm.
N
t zsc h i a
pa 1 ea
(Kutz.)
N
tzsch i a
pa 1 ea v* deb i 1 i s
(Kutz*)
N
tzsch i a
pa 1e a cea
Grun*
N
tzsch ia
pur a?
Hust*
N
t zsch i a
recta
Hant z *
N
tzsch i a
r omana
Grun.
N
t zsch i a
so c i ab i1i s
Hu st.
N
tzsch ia
Sp*
Hust.
N
tzsch i a
sp i c u1um
N
tzsch ia
subac i cu1aris
Hust *
N
tzsch i a
sub 1 i near i s
Hust *
N
tzsch ia
sub 1 inear i s ?
Hust *
N
t zsch i a
subrostrata
Hust *
N
tzsch i a
tenuis
W* Sir*
N
tzsc h i a
valdestrita
A 1eem £
Opephora martyi
Rhizosolenia eriensis
Rhizosolenia Icngiseta
Rhizosolenia sp *
Rhoiocosphenia curvata
Ske I etonema pctarros
Stauroneis smithii v* minuta
Stephanodiscus alpinus
S tephanodi scus
Stephanod i sou s
Stephanod i scus
S te phano di sc us
S tephanodi sc us
Stephanod i scus
Stephanod i scus
Stephanodi scus
Stephanod i scus
Stephanod i sc us
Stephanod i scus
Stephanod i scus
Stephanod i scus
Stephanod i scus
Stephanod i scus
a I p i nus ?
D i nderanus
b inder anus?
hantzsch i i
m inu tus
n iagarae
sp*
sp* #0 3
sp* -auxospore
subt i I i s
tenu i s
tenu is v• #01
tenuis v* *02
tenu i s ?
transiIvanicus
Sur i r e 11 a angusta
Synedra amphicephaI a v. austrica
Synedra cyclopum
Synedra deIicatissima v* angustissima
Synedra f ante i I ica
Synedra filiformis
Hust •
Her i b.
H • L • S id •
Zach •
(Kutz.) Grun.
(Weber) Hasle £ Evens*
Haw*
Hust *
Hust *
(Kutz.) Kr i eg.
(Kutz*) Kr ieg.
Grun *
Gr un •
Ehr •
(Van Goor) A. CI *
Hust *
Hust*
Pant *
Kutz *
(Grun*) Hust*
Brut schy
Grun.
Kutz *
Grun •
-------
254
SPECIES LIST - LAKE MICHIGAN PhYTOPLANKTON I19b3)
DIV TAXON
AUTHORITY
bAC Synedra
Syned r a
Synedra
Synedra
Synedra
Synedra ulna
S ynedr a ulna
Synedra uIna
Synedra ulna
T a b e I I a r i a
Tabe I I ar i a
Tabe I I ar i a
Tabe I I a r i a
f i I i f crit i s
mini sou I a
parasitica
radians
sp.
e x i I i s
v• cha s eana
v . dan i c a
v. I on g i ss i ma
f e re s t ra ta
ferestrata
fIocclIo sa
fIocculb sa
geniculata
I i near i s
CAT Vacuolaria sp.
CHL Ankistrodesmus
Ank i strodesmus
Ank i strodesmus
Ank i st rodesmus
fa I c at us
ge I i factum
sp. #01
sp. ?
Ar thr odesmus
Botryococcus
Carteria sp.
ChIamydocapsa
ChIamydocap sa
Chlamydomonas
Ch I amy dorronas
Ch I amydotronas
CIosteri ops i s
CIo ster i um
C loster i u m
Coe lastrum
Coelastrum
Coe lastrum
Coenocyst i s
b i t i du s
b raun i i
pIank to n i ca
sp.
sp.
sp.
sp.
sp.
ac i cuIar e
gr ac i I e
cairbr icum
m i croporum
sp.
sp.
- ovoid
- sphere
Cosmar ium sp.
Crucigenia irregularis
Crucigenia quadrata
Crucigenia rectangu laris
Dictyosphaerium ehrenbergianum
D i ctyosphaer i urr pulchellum
Elakatothrix gelatinosa
Elakatothrix viridis
EIakato th r i x viridis?
G I oedact i n i um liirneticum
Golenkinipsis sp.
Green coccoid
Green cocco i d
Green cocco i d
Green coccoid
Green cocco i d
Green coccoid
0 C4
- aci cuIar
- bac i I I i f orm
- b i c e I I s
- fusiform
A. CI.
Gr un.
W. Sm.
Kutz.
(Nitz.) Ehr.
Thomas
(Kutz.) V.H.
( W . Sm . ) tir un,
Kutz .
A. CI.
(Roth) Kutz.
Koppen
(Cor da)
(Chod. )
Br eb .
Kutz .
Ra I f s
Bour r .
(m. £ G.S. West) Fott
T. West
Br eb .
Ar ch.
Nag. in A,
Braun
Wide
Mo r r en
A. Braun
Nag.
Wood.
W i I I e
( Snow) Pr i ntz
(Snow) Pr i ntz
G. M. S m.
-------
255
SPECIES LIST - LAKE MICHIGAN PHYTOPLANK TON (1983)
DIV TAXON AUTHORITY
CHL Green coccoid
Green coccoid
Gr een cocco i d
Green coccoid
Green coccoid
Green coccoid
K i r chner i eI I a
Monoraphid i um
Monoraph id i um
Monoraphid ium
Monoraph id i um
Monoraphid ium
Monora ph i dIum
Ne phr ocy t i um
Nephr ocyt i um
- fusiform bicells
- cocystis-IiKe biceli
- ova I
- reniform
- sphere
- sph er e (large)
co nto r ta
contor turn
i r regulare
rr i nut um
saxat i I e
set iformae
to r t i I e
Aga r chi a num
Ii mneti c um
Gedogonium sp.
Oocyst i s sp.
Oocystis sp. Ml
Oocyst is borge i
Oocyst is crassa
Oocyst i s I acustri s
Oocystis marscnii
Oocyst i s par va
Oocyst i s pus i I I a
Oocyst i s soli tar ia
Oocyst i s submarina
Pediastrum sp.?
Phacotus minuscula
Phacotus sp.
Planktonema lauterbornii
Planktonema sp*
Pteromonas sp.
Pyramidomonas sp.
Scenedesmus aclit. ina tus
Scenedesrrus
Scenedesrrus
Scenedesirus
Scenedesmus
Scenedesmus
Scenedesirus
Scenedesmus
Schro eder ia
Sphaerellocystis
SphaereI Iocyst i s
eccr n i s
quaori cauda
quadr i cau da v •
sccur if ormi s
s er r atu s
sp.
sp i nosu s
set i ger a
I a cu str i s
lateral is
I ongsp i na
Sphaerocystis schroeteri
Stichococcus sp.
Tetraedron caudatum
Tetraedron minimum
Tetraspora lacustris
Tetrastrum glabrum
Treubaria planktonica
Treubaria set igera
(Schirid.) Bohlrr.
(Thur.) Kom.-Legn.
(G.M. Sm.) Kom.-Legn.
(Nag.) Kom.-Legn.
Kom.-Legn.
(Nyg .) Kom.-Legn.
(W. i In.) Kom.-Legn.
Nag.
(G.M. Sm.) G.M. Sm.
Snow
Wittr. in Wittr. I Nord.
Chod •
Lemm.
West L West
Hansg.
Wittr. in Wittr. I Nord.
Lagerh.
Bourr.
Schm i dIe
(Lagerh.) Choa.
(Ra I fs) Chod.
(Turp.) Breb.
(Chod.) G.M. Sir.
PI ay f.
(Corda) Bohlm
Chod.
(Schroed.) Lemm.
Sku ja
Fott & Novak*
Chod •
(Corda) Hansg.
(A. Braun) Hansg.
Lemm.
(G.M. Sm.) Korch.
(Arch.) G.M. Sir.
-------
256
SPECIES LIST - LAKE MICHIGAN PHYTOPLANKTON (1983)
UIV T AXON AUTHORITY
CHR B i tr i ch ia chodat i i
Bitrichia oh r i d i ana
Ch romuli na s p.
Chrysococcus sp.?
Chrysolykos angulatus
Chrysolykos planktonicus
Chrysolykos sktjae
Chrysolykos sp.
Chrysosphaerella longispina
Dinobryon - cyst
Dinobryon acuminatum
ba va r i c um
bor ge i
cyI i nori c urn
divergens
eurystcma?
serttlaria
soc i a I e
soc i a Ie v
soc i a Ie v
sp.
st okes i i v.
tubaeformae
utriculus v. tabellariae
sp. ?
sp.
Dinobryon
Dinobryor
Dinobryon
Dinobryon
Dinobryon
Dinobryor
Dinobryon
Dinobryon
Dinobryon
D i nobr yon
D i nobr yon
Dinobryon
D i nobr yon
Halobryon
Haptophyte
arrer i canum
st i ptatum
ep i p lankton i cum
Kephyrion
Kephyr ion
Kephyr i on
Kepnyr i on
Kephyr ion
Kephyr i on
Kephy r i on
Kephyr i on
Mallomonas
Ma I Iomo nas
Ma I Iomona s
Ochr omona s
Oc h romona s
Ochr omonas
Ochromonas
Paraphysomonas
Paraphysomonas
Pseudokephyr i on
Pseudokephyr i on
Pseudokephyr i on
Pseudokephyr i cn
P seudokephyr i on
Unidentified
Un i dent i f i ed
cupul iforrrae
do I i cIum
rub i-caIu st r i
sp.
sp. *)1 -P seudokephyr i on
sp • HI
sp. #3
sp i ra I e
majcrensi s
sp.
sp. #3
sp •
sp.
sp.
sp.
en tz i i
- oval
- ovoid
- sphere
sp •
sp. ?
con i c urr
I at um
it i I I e r e n s e
sp. 0 1
undu I at i ss imum
coccoia - ovoid
coccoi o - spher e
(Rev.) Chod.
(Fott) Nich.
(Ki I I en ) Nauw.
Mack .
(Nauw.) Bourr.
Laut. em. Nich.
Rutt.
Imh o t
Lemm •
Imho f
Imhof
(Stokes) Lemm.
Eh r •
Ehr .
(Brunnth . ) Bac hm .
(Stein) Lemm.
Sku ja
Nyg.
Lemm.
Conr.
Conr •
Conr .
(Lack .) Conr .
Sku ja
( Sch iI I•) Schum.
( Sch i I I. ) Schum •
Nich.
Schert f.
Un ident i f i ed
Un i dent i f i ed
coccoi ds
I or i ca te -
sphere
-------
257
SPECIES LIST - LAKE MICHIGAN PHYTOPLANK TON ( 1983 )
UIV TAXON AUTHORITY
CHR Unidentified I oricate-fI age I I ate sphere
COL
CRY
CYA
Bicoeca campanulata
Bicoeca lacustris?
Bicoeca mitra v.?
6 i coeca sp•
B i coeca sp . #C4
Bicoeca tubifcrmis
Codonos i ga sp *
Colorless flagellate
Colorless flagellate
ColorJess flagellates
Mas t i geI I a sp.
Monos i ga ovata
Salpingoeca arrphcrae
Sa I p i ngoeca gracilis
Sa I p i ngoeca sp.
Stylotheca aurea
- ovoid
- sphere
Chroomonas
Ch r oomonas
Chroomonas
Chr oomonas
Cr yptomonas
Cr yp tomonas
Cr yptomonas
Cr yptomonas
Cryptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
C ryp tomonas
Cr yptomonas
Cr yptomonas
C r ypt omona s
Cryptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Cr yptomonas
Rhodomonas
Rhodomonas
a c l ta
c a uda ta
no r stedt i i
pochmanni
- cyst
brev is
brev i s?
caidata
er csa
ercsa v* reflexa
Iobata
marsson i i
rrarsson it v. ?
ovata
parapyrenoidifera
phaseolus
pus i I la
pyrenoi oi fera
reflexa v. er osa
rostrat if ormi s
sp.
tenu is
tetrapyreni od iosa
lacustris
lens
Rhodomonas minuta
Rhodomonas minuta
S ennI a parvuI a
Sennia parvula?
v• nannop lank t i ca
Anabaena flos-aQiae
Anabaena sp.
Anacystis marina
(Lack.) Bourr. em. Skuja
J. C t a r k
Skuja
Kent
Kent
Clark
(Bachm.} Boloch.
Ute r m•
Ge i t.
Hansg.
Hube r-Pest.
Sch iI I.
Schill.
Sch i I I •
Ehr .
Mar s s.
Korsch.
Skuja
Skuja
Ehr .
Skuja
Skuja
Bachir.
Gelt I.
Skuja
Pasch.
Skuja
Pasch. L Rutt.
Pasch. £ Rutt.
Skuja
Skuja
Skuja
Skuja
(Lyngb.) Breb•
(Hansg.) Dr• L Daily
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258
SPECIES LIST - LAKE MICHIGAN PHYTOPLANKTON (1983)
DIV TAXON AUTHORITY
CYA Anacystis montana
Anacystis montana v. minor
Anacyst is therrralis
Aphanothece gtlatinosa
Coccochloris elabans
CoccochJoris peniocystls
C oe I ospha e r i u rr. naegelianum
DactyIococccpsis Smithii
DactyIococcopsis sp.
Gloeothece ruprestr is
Gomphosphaeria lacustris
Lyngbya Ii mnet i cum
Oscillatoria acardhii
Oscil latoria
Osc iI latoria
Oscillatoria
Oscillatoria
OscilIato ri a
Oscillatoria
Oscil latoria
Oscillatoria
Un i dent i f i ed
EUG EugIena sp.
I irrtnet i ca
I imnet i ca?
rr i n ima
sp.
suobrev i s
tenuis
tenuis v• natans
tenu i s v . ter g i s t i ria
bIue-g r e ens
PYR Amph i d in i urn sp .
Ceratium hirundinella
0 i not I aye I I ate cyst
Gymnodinium sp.
Gymnodinium sp. #1
Gymnod in i urr sp . #2
Gymnod inium sp. #3
P er i d i n i um c i nc turn
Peridinium inconspicuum
Peridinium sp.
Dr. & Daily
Dr. & Daily
(Menegh • ) Dr
(Henn.) Lemm
Dr. £ Daily
(Kut z. ) Dr .
Unge r
Chod. £ Chod.
L Da i I y
I Daily
(Lyngb.) born.
Chod .
Lemm.
Gom.
Lemm.
Lemm .
G i ckIh •
Schm i d.
C . A . A g .
Gom .
( K ut z • ) Rab h .
(O.F.Mul I.) Schrank
(Mull.)
Lemm.
Ehr
UNI Unidentified ccccoid flagellates
Unidentified flagellate #01
Unidentified flagellate #03
Unidentified flagellate - ovoid
Unidentified flagellate - spherical
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259
GREAT LAKES ZDOP LANK TON SPECIES LIST
LAKE ERIE
(1983)
DIVISION TAXON
Calano ida
CIadocer a
Copepoda
Cyclopoida
Harpactlco ida
Rot i fera
Ca la no i d
0 Iap tomus
D i ap tomus
0 i ap tomus
DIap tomus
0 i ap tomus
Ep i schura
Eu ry temora
copepodi te
ash land i
m inutus
oregonens 1 s
s i c i t i s
s i cI Io i de s
lacustr i s
af f i n i s
LImnoca lanus macrurus
Senecella calanoides
Bosmina longirostris
Ceriodaphnia lacustris
Ceriodaphnia reticulata
Ce r i odaphn ia sp.
Chydorus sphaericus
Oaphnia catawba
Oaphnia gaiaeta mendota
Oaphnia retrocurva
Oaphnia schodIerI
Oaphnia sp*
Dlaphanosoma ecaudis
Diaphanosoma Ieuchtenbergianum
Eubosmina coregoni
Eurycercus lamellatus
Ho I opediurn gibberum
Ilyocryptus sptnifer
Leptodora k indt iI
SIoa crystal Iina
Copepoda NaupIiI
Cyclopoid — copepodite
Cyclops bicuspidatus thomasi
Eucyclops edax
Eucyclops prionophorus
Mesocyclops edax
Tropocyclops prasinus mexlcanus
HarpactIcoida
Alona quadranqularis
Ascomorpha ecaudis
Ascomorpha sp*
Asplanchna prlodonta
6delloId RotIfera
Brachionus bldentata
Brachlonus caudatus
Brachionus sp*
Co 11otheca sp.
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GREAT LAKES ZOOPLANKTON SPECIES LIST
LAKE ERIE
(1983)
DIVISION
k o t i f e r a
TAXON
Co no ch i Ioi des sp •
Conochilus unicornis
Eu ch Ian i s sp*
F i Ii na Iong i seta
Gastropus sp*
Gastropus stylifer
Keilicottia longispina
Ke ra teI I a co chI ear i s
Ke ra teI la crassa
Ke ra teI I a ear Ii nae
Ke ra teI I a hi emal i s
Keratella quadrata
Lepade I la sp.
NothoIca foIiacea
Notholca laurentiae
Notholca squamula
PIoesoma sp•
Polyarthra dolichoptera
Po lyar thra major
Po I yar thra remata
Polyarthra vulgaris
Synchaeta sp.
Trichocerca cyiindrica
Trichocerca multicrinis
Tr i choc er ca s imiIts
Tr ichoc erca sp.
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261
GREAT LAKES ZOOPLANKTON SPECIES LIST
LAKE HUkON
(1983)
DIVISION TAXON
Ca I ano i da
CIadoce ra
Copepoda
Cyc I opo i da
Mys i dacea
Rot I fera
Calanoid - copepodite
Diaptomus ashlandi
01ap tomus m i nutus
Diaptomus oregonensis
0 i ap tomus s i c iIi s
Diaptomus siciioides
Ep i s chu ra Iacustri s
Limnoca lanus macrurus
Senecella calanoides
Bo sm i na
Daphn i a
Daphn i a
Da phn i a
Daphn i a
Daphnia
Da phn i a
Da phn ia
Di aphanosoma
Oi aphanosoma
I ong i rostr i s
catawba
dub ia
gaiaeta mendota
puI i car i a
retrocurva
schodler i
sp.
leuchtenberg ianum
sp.
Eubosmina coregoni
Hoiopedium gibDerum
Lept odo ra k indt i i
Polyphemus pediculus
S i oa cr ystaI Iina
Copepoda NaupIi i
Cyclopoid - copepodite
Cyclops bicuspidatus thomasi
Cyclops vernalis
Mesocyclops edax
Tr opocycI ops prasinus mexlcanus
My si s re I I eta
Ascomorpha sp*
Asplanchna priodonta
Cephalodelia sp.
CoJiotheca sp.
Conochi lus unicornis
Eu ch Ian Is sp.
F i11na Iong i seta
Gastropus sp.
Gastropus sty Iiter
Kellicottia iongisplna
Keratella cochiearis
Keratella cochiearis hispida
KerateI la crassa
Keratella earlinae
-------
262
GREAT LAKES ZOOPLANKTON SPECIES LIST
LAKE HURON
(1983)
DIVISION TAXON
Rotifera Keratella hiemalis
Keratella quadrata
Mo no sty I a Iunar i s
No thoIca to Ii acea
Notholca laurentiae
Notholca squamula
P I oe soma sp .
Polyarthra dolichoptera
Po lyar thra major
Po I yar thra remata
PoIyar thr a vu I gar i s
Rotifer - soft body
Synchaeta sp*
Trichocerca cylindrica
Trichocerca multicrinis
Tr ichocerca sp*
Trichotria pocillum
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263
GREAT LAKES ZOOPLANK TON SPECIES LIST
LAKE MICHIGAN
( 1983 )
DIVISION TAXON
Calanoida
CIadocera
Copepoda
CycIopo i da
Harpact i coI da
Mys idacea
Rotifers
Cala no i d -
0 i ap tomus
D i ap tomus
0 iap tomus
D i ap tomu s
D i aptomus
Ep i s chu ra
Eu ry temora
copepodite
ash I ana i
m i nutus
oregonens i s
s i c i I i s
s i c iIo t de s
iacustr is
af f i n i s
Limnoca I anus macrurus
Senecella calanoides
A Iona af f i ni s
Bosmina longirostris
Camptocercus rectirostris
Ceriodaphnia lacustris
Chydor i dae
Chydorus sphaericus
Oaphnia catawba
Daphnia dubia
Daphnia galaeta mendota
Daphnia inmatures
Daphnia longiremis
Daphnia middendorffiana
Daphnia pu I i car ia
Daphnia retrocurva
Daphnia schodleri
Daphnia sp*
Diaphanosoma Ieuchtenbergianum
Eubosmina coregoni
Eurycercus lamellatu.s
Hoiopediua gibberum
Ilyocryptus spinifer
Leptodora kindtIi
Polyphemus pediculus
Copepoda Naup I i i
Cyclopoid - copepodite
Cyclops blcuspidatus thonasI
Eucyclops prionophorus
Mesocyclops edax
Tropocyclops prasinus mexicanus
Harpact ico i da
MysIs relIcta
Ascoaorpha sp«
Asplanchna priodonta
Brachionus quadridantatus
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264
GREAT LAKES ZOOPLANKTON SPECIES LIST
LAKE MICHIGAN
(1983)
DIVISION TAXON
Rotifera Cephalodella sp.
Co I Iotheca sp•
Co no ch i Ic i de s sp .
Conochilus unicornis
Encentrum sp.
Eli ch I an i s sp .
Fi Ii na Iong i seta
Ga strop us stylifer
Kellicottia longispina
Keratella cochlearis
Ke ra teI I a crassa
Ke ra teI I a ear Ii nae
Keratella hi emaI i s
Ke rate I la quadrata
Lecane tenu i seta
Monosty la sp.
Notholca acuminata
No thoIca f oIi acea
Notholca laurentiae
Notholca squamula
Notholca striata
PIoesoma sp•
Polyarthra dolichoptera
Po lyar thra major
Po lyar thra remata
Polyarthra vulgaris
Synchaeta sp*
Trichocerca cylindrica
Trichocerca multlcrlnis
Tr ichoc crca sp*
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-905/2-87-002
3. RECIPIENT'S ACCESSIOI*NO.
4. TITLE AND SUBTITLE
Phytoplankton and Zooplankton Composition, Abundance
and Distribution: Lake Erie, Lake Huron and Lake
Michi gan-1983
5. REPORT DATE
ADril 1987
6. PERFORMING ORGANIZATION CODE
5GL
7. AUTHORIS)
Joseph C. Makarewicz
8. PERFORMING ORGANIZATION REPORT NO.
GLNP0 Report No. 87-06
9..PERFORMIIMG ORGANIZATION NAME AND ADDRESS
State University of New Yorlc at Brockport
Department of Biological Sciences
Brockport, New York 14450
for the Research Foundation of State University of New
York
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
R005/72-01
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Great Lakes National Program Office
230 South Dearborn Street
Chicago, Illinois 60604
13. TYPE OF REPORT AND PERIOD COVERED
FINAL
14. SPONSORING AGENCY CODE
Great Lakes National Program
Office-USEPA, Region V
15. SUPPLEMENTARY NOTES
Paul Bertram
Pro.iect Officer
16. ABSTRACT
An in-depth comparison of phytoplankton and zooplankton from Lakes Erie, Huron
and Michigan is presented based on extensive lake-wide surveys during spring,
summer and autumn of 1983. This comparison was achieved by the application of
standard and consistent identification, enumeration and data-processing
techniques of plankton along north-south transects in Lakes Huron and Michigan
and east-west transects in Lake Erie.
For Lakes Erie, Huron and Michigan respectively, 436, 411 and 452 algal taxa
and 71, 61 and 73 zooplankton taxa were identified. Based on indicator species
and species associations, the plankton assemblage was consistent with a
mesotrophic-eutrophic designation for Lake Erie, oligotrophic designation for
Lake Huron, and mesotrophic-oligotrophic designation for Lake Michigan.
Species lists for each are provided. Original source data for each station
visit are provided in the attached microfiche.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. 1DENTIFIERS/QPEN ENDED TERMS
c. COSATI Field/Group
Lake, Michigan, Huron, Erie
Phytoplankton
Zooplankton
Picoplankton
through the National
Technical Information Service(NTIS)
Springfield, VA 22161
IS. SECURITY CLASS /This Report)
21. NO. OF PAGES
280
20. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (9-73)
* U S. GOVERNMENT PRINTING OFFICE: 1M7 744-960
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