Preliminary Results of the 1978-1979 Lake Erie
Intensive Study - Phytoplankton
by
David S. DeVault III
and
David C. Rockwell
For
U.S. Environmental Protection Agency
Great Lakes National Program Office
536 South Clark Street Room 102
Chicago, Illinois 60605 %
EPA-905-R-81-100
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Introduction
As part of the International Joint Commission's monitoring plan on the Great Lakes, intensive
surveys of Lake Erie were undertaken in 1978 and 1979 by the U.S. Environmental Protection Agency.
These surveys included monitoring of phytoplankton populations in the open waters on nine cruises in
each year (Table 1) to detect changes in the quantity and quality of phytoplankton reflective of changing
water quality and to provide data by which future changes may be measured. This report includes results
of the 1978-79 study as well as a discussion of changes occurring between 1978 and 1979.
Methods
Phytoplankton samples were collected according to the following sampling regime. When the
lake was thermally stratified, samples were collected from 1 meter, 1 meter above the metalimnion, at the
thermocline, 1 meter above the hypolimnion, and 1 meter above the bottom. When thermal stratification
was not evident samples were obtained at 1 meter, mid-depth, and 1 meter above the bottom. The
exception to this was on the March 1979 cruise when samples were obtained at the 1 meter depth from a
U.S. Coast Guard helicopter. Table 1 gives the cruise dates in 1978 and 1979. In 1978 phytoplankton
samples were collected from all stations on all cruises (Figure 1). In 1979 a reduced station network was
implemented (Figure 2).
Phytoplankton samples were obtained from the same opaque 8 liter Niskin bottles used for
nutrient-analysis. Following removal of water for nutrient analysis a 500 ml aliquot of sample was drawn
into an 540 ml polyethylene bottle and 10 ml of modified Lugols solution added. Samples were returned
to Chicago where analysis and quality control were carried out by USEPA's Central Regional Laboratory
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(CRL). In CRL the samples were shaken vigorously for several minutes and 10 ml poured into settling
chambers and allowed to settle for 35 to 48 hours. Organisms greater than 10 |o.m were enumerated and
identified at 250 with 2 perpendicular strips 13.6 mm long (10.93 mm2) counted. Organisms less than 10
\i.m were enumerated and identified at 500 X with 2 perpendicular strips 13.6 mm long (5.55 mm2) being
counted. All analysis was performed using Lietz Ultralux inverted microscopes. All data was expressed
as cell/ml.
Due to the large volume of samples generated and other commitments of Great Lakes National
Program Office (GLNPO); resources were not available for exhaustive station by station measurements
for the calculation of biovolumes. Instead the following regimen was used to generate approximate cell
dimensions for calculating biovolume. Organisms or cells were measured in surface samples from
stations 61, 84, 58, 50, 51, 86, 30, 79, 18, 80, and 5 on cruise numbers 4, 6, and 9 in 1978. At least 10
cells (usually many more) of each common species were measured. Less common species were measured
as they occurred. These measurements were combined and mean dimensions calculated for each species.
Geometric shapes were approximated and mean volumes calculated. When species not measured in this
process or were measured infrequently (n <10), biovolumes supplied by the Center for Lake Erie Area
Research at Ohio State University, State University of New York at Buffalo, or obtained from the
literature were utilized. Biomass was calculated assuming a density of 1.
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Results
Seasonal Variation 1978
In 1978 total phytoplankton biomass in the western basin ranged from 2.0 g/m3 to 9.1 g/m3. Total
biomass (Figure 3) decreased from 2.0 g/m3 to 1.1 g/m3 between May and June before increasing to the
observed maximum of 9.1 g/m3in August. Following the August peak, biomass declined to 1.25 g/m3 in
November. The population was dominated (Figure 4) in turn by Diatomeae (May), Cryptomonadinae
(June), Dinophycinae (July), cyanophyta (August), Diatomeae (September-October), and Cyanophyta
(October-November). The seasonal variations in biomass of major taxonomic groups are given in Figures
5 and 6.
Total phytoplankton biomass in the central basin in 1978 was less than that observed in the
western basin, ranging from 1.0 g/m3to 3.1 g/m3 (Figure 7). Biomass decreased from 2.8 g/m3 in May to
1.05 g/m3 in June before reaching the maximum observed value of 3.0 g/m3 in July. Following the July
maximum, biomass decreased steadily to the low of 1.0 g/m3 observed in November. The Diatomeae
dominated the plankton from May through late June (Figure 8). In July the population was nearly equally
dominated by the Chlorophyta (26%) and Dinophycinae (27%). The Chlorophyta continued to dominate
the central basin phytoplankton throughout the rest of the 1978 study period. The seasonal variations in
biomass of major taxonomic groups are given in Figures 9 and 10.
The lowest total phytoplankton biomass and least seasonal variation in 1978 occurred in the
eastern basin (Figure 11) where biomass ranged from a low of 0.4 g/m3 in November to a high of 2.2 g/m3
in May. The major group composition (Figure 12) resembled that of the central basin with the Diatomeae
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dominating the plankton on the May and June cruises and the Chlorophyto dominating from July
through early October. The summer dominance of the Chlorophyta was, however more pronounced in
the eastern basin where it comprised over 88% of the total biomass. The seasonal variations in major
taxonomic groups are given in Figures 13 and 14.
Seasonal Variation 1979
Caution should be exercised when considering seasonal variations in 1979. Vessel breakdown
and other technical difficulties resulted in data being available for seven cruises in the western basin, six
in the central and five in the eastern basin.
The most complete data set in 1979 is for the western basin where total biomass ranged from a
low of 2.0 g/m3 in April to a high of 17.3 g/m3 in November (Figure 15). Biomass remained relatively
constant (2.0 g/m3 to 2.35 g/m3) on the April, May, and July cruises. By early August phytoplankton
biomass had increased to 15.7 g/m3 primarily as a result of large increases in Diatomeae (5.8 g/m3)
(Coscinodiscus rothii 3.1 g/m3) and Cyanophyta (7.3 g/m3) (Aphanizomenon flos-aquae 3.6 g/m3)
biomass. Following a decrease to 12.3 g/m3 in September, total biomass again increased reaching 17.4
g/m3 in November. The November peak resulted from very high 14.1 g/m3 Diatomeae biomass (Melosira
sp. 6.7g/m3, Stephanodiscus binderana 2.8 g/m3, S. Niagarea 2.5 g/m3) as well as a high Cyanophyta
biomass (2.1 g/m3) (Aphanizomenon flos-aquae 1 g/m3). As in 1978, the western basin phytoplankton
was dominated by the Diatomeae on the early cruises while the Cyanophyta dominated the early to
mid-summer cruises (Figure 16) with the Diatomeae again dominating in September through November.
The seasonal variations in major taxonomic groups are given in Figures 17 and 18.
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The central basin was similar to the western basin in that large diatom populations occurred on
the October (2.2 g/m3) and November (7.5 g/m3) (Melosira sp 3.5 g/m3, S. binderana 1.2 g/m3, S.
Niagarea 2.5 g/m3) cruises. In 1979 total phytoplankton biomass in the central basin ranged from 1.5 g/m3
to 8.4 g/m3 (Figure 19). The spring (March and May) cruises were dominated by the Diatomeae, with the
Chlorophyta dominating the plankton on the July cruise and the Diatomeae dominating on the September,
October and November cruises (Figure 20). The seasonal variations of major taxonomic groups in the
central basin in 1979 are given in Figure 17.
Total biomass in the eastern basin in 1979 ranged from a low of 0.65 g/m3 in March to a high of
1.25 g/m3 in October (Figure 23). As in the central basin the spring cruise (March) was dominated by
Diatomeae. the summer (July through September) by Chlorophyta and the fall (October and November)
by Diatomeae (Figure-24). (Figures 25 and 26) give the abundance of major taxonomic groups.
Species Composition
The relative abundance of common species in 1978 and 1979 are given in Tables 2 through 7.
These tables also give the trophic preference of those species which have well defined trophic preference
(Stoermer and Yang 1970, Tarapchak and Stoermer 1976, Munawar 1981).
The 1978 spring cruise (May 18-25) in the western basin was dominated by Melosira sp. with
Tabellaria fenestrata and Closterium lunula as sub-dominants. The late spring (June 6-15 and June
23-July 2) cruises were dominated by Cryptomonas erosa and Covata with Mougeotia sp. and Ceratium
hirundinella sub-dominants on the June 23-July 2 cruise. The three summer (July 19-September 6)
cruises were dominated by Ceratium hirundinella, Aphanizomenon flos-aquae, and Coscino discus rothii.
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Sub-dominants during this period included Cosmarium spp. and Melosira, spp. The fall cruises (October
3-November 16) were dominated by Oscillatroia sp. with Melosira sp. and Coscinodiscus rothii as sub-
dominants.
In 1979 the early spring cruises (March 27-April 20) in the western basin were dominated by
Fragillaria sp. and Melosira sp. with Diatoma tenue and Stephanodiscus binderanus sub-dominate in
April. The summer period (July 11-August) was, as in 1978, dominated by Aphanizomenon flos-aquae
with Ceratium hirundinella and Coscinodiscus rothii as sub-dominants. The fall (September
11-November 16) cruises were dominated by Melosira sp., and Stephanodiscus niagarae with
Coscinodiscus rothii, Aphani zomenon flos-aquae, and Stephanodiscus binderanus as sub-dominants.
The 1978 spring (May 18-25) cruise in the central basin was dominated by Asterinonella formosa
with Melosira sp. a sub-dominant. By late spring (June 6-July 2) an unidentified non-green flagcallate
and Fragilaria crotonensis were the dominant phytoplankton organisms with Cryptomonas erosa and an
unidentified pennate diatom important contributors to the total biomass. The summer (July 19September
6) cruises were dominated by eutropic forms, such as Ceratium hirundinella and Oocystis borgei with
other eutrophic species such as Aphanizomenon flos-aquae. Stephanodiscus niagarae, and Scenedesmus
bijuga common. The fall (October 3-November 16) cruises were dominated by Stephanodiscus niagarae.
and Cryptomonas erosa. Oscillatoria sp. and Crvptomonas ovata were sub-dominates. Eutrophic
indicators such as Aphanizomenon flos-aquae, Oocystis borgei; and Oscillatoria sp. were, common.
In 1979 the central basin spring (March 27-May 26) cruises were dominated by the
Stephanodiscus niagarea with Stephanodiscus binderanus, Diatoma tenue var. elongatum, Fragilaria sp.,
Melosira sp., Tabellaria fenestrata, and Rhodomonus minuta common. The summer (July 11-August 4)
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cruises were dominated by Ceratium hirundinella with eutrophic indicators such as Coelastrum
reticulatum, Staurastrum paradoxum, Oocystis borgei, Aphanizomenon flos-aquae. and Coscinodiscus
rothii common. The fall cruises (September 11-November 16) were dominated by Stephanodiscus
niagarea in September and October while Melosira sp. dominated the November cruise.
In the eastern basin the spring 1978 (May cruise was dominated by Stephanodiscus binderanus
with Asterionella formosa a sub-dominate. By late spring (June 6-July 2) an unidentified pennate diatom
and Cryptomonas erosa were the dominant and subdominant species. Diatoms such as Fragilaria
crotonensis, and Tabellaria fenestrata were important.
The summer (July 19-September 6) cruises were dominated by eutrophic green and blue-green
species such as Anabaena flos-aquae, Scenedesmus bijuga, and Oocystis borgei. Other typically
eutrophic forms such as Ceratium hirundinella and Staurastrum paradoxum were common. By the fall
(October - November) cruises diatoms were becoming relatively more important in the plankton with
Tabellaria fenestrata and Stephanodiscus niagarea common. The fall 1978 cruises were dominated in turn
by Oocvstis borgei. Tabellaria fenestrata, and Cryptomonas erosa.
In 1979 only five phytoplankton cruises were completed in the eastern basin. Three of these
were clustered in the September-November period. The Spring (March) cruise was dominated by
Stephanodiscus niagarea which comprised over 78% of the total biomass. The summer and fall cruises
for which data is available indicates a successional pattern similar to that observed in 1978.
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Horizontal Variation
Figures 27 and 28 illustrate the horizontal distribution of total biomass in 1978 and 1979. In 1978
a growth pulse had apparently begun in the central and stern basins prior to our May cruise. A second
pulse began in the western basin on the June 28 cruise which spread into the central and eastern basins in
July. Throughout the 1978 study season total biomass tended to be higher near shore in all basins. The
western basin, particularly west of the Detroit River and southwest of the Bass Islands exhibited the
highest total biomass. Biomass concentrations in the central and eastern basins were surprisingly similar.
In 1979 total biomass at most stations in the western and central basins (from August through
November) was substantially higher than that observed in 1978 while eastern basin concentrations were
relatively unchanged from the previous year.
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Discussion
In both years of the study there was a west to east decrease in total biomass and change in
dominant groups. In 1978 mean total biomass ranged from 4.0 g/m3 in the western basin to 1.8 g/m3 in the
central and 1.2 g/m3 in the eastern basin. In 1979 the reduced station network and limited number of
cruises yielded mean biomass of 9.4 g/m3, 3.4 g/m3, 0.9 g/m3 in the western, central, and eastern basins
respectively. Between May and November, both years, the Cyanophyta was most common in the western
basin, the Diatomeae in the central and the Chlorophyta in the eastern basin. The large dominance of
diatoms on the April cruise in 1979 resulted in the Diatomeae being the dominate form in the, western
basin that year. (Munawar and Munawar (1976) reported similar dominance of major groups in the three
basins between April and December 1970.
The major observation of our study was the increase in phytoplankton biomass observed between
1978 and 1979 in the western and to a lesser extent in the central basin. This was particularly evident in
the western basin where a nearly complete data base in 1979 and similar station locations in 1970, 1978,
and 1979 allows a more direct comparison than can be made in the other basins. Figure 29 illustrates the
cruise means for total phytoplankton biomass in 1970 (Munawar and Munawar 1976), 1978, and 1979 at
stations 50, 51, 55, 58, and 61. The data indicates that western basin biomass between April and August
in both 1978 and 1979 was substantially below that observed in 1970. However, in the latter portion of
the 1979 season total biomass frequently equalled or exceeded that observed in 1970.
While the lack of May and June cruises in 1979 prevents direct comparison over the season, the
data can be compared for the July through November period. This is given in Table 8 and shows the large
biomass increase over 1978 levels that occurred in the later half of 1979. This increase is supported by
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field observations of visible blue-green algae blooms over large areas of the western basin in August,
September, and October 1979. We also observed blooms associated with whitings (Schelski & Callender
1970) probably as a result of CaCO3 precipitation, in August 1979.
Vollenweider (1968) has used maximum phytoplankton biomass as an indicator of trophic status.
He classifies lakes with maximum biomass <1.0 g/m3 as ultra-oligotrophic, 3 to 5 g/m3 as mesotrophic
and those >10 g/m3 as highly eutrophic. Based on this system, the western basin of Lake Erie would be
classified between mesotrophic and highly eutrophic (9.1 g/m3) in 1978 and as highly eutrophic (17.3
g/m3) in 1979. The central basin would be considered mesotrophic (3.1 g/m3) in 1978 and between
mesotrophic and highly eutrophic (8.4 g/m3) in 1979. The eastern basins with maximum biomass of 2.2
g/m3 and 1.25 g/m3 would be considered mesotrophic both years.
The above classification is consistent with the trophic preference of common species given in
Tables 2 through 7. In the western basin; between 44% (in 1978) and 62% (in 1979) of those species
comprising 5% or more of the total biomass have been classified by at least one author as eutrophic. In
the central basin 41% and 55% fall in this category in 1978 and 1979. The percentage of eutrophic
species in the eastern basin in 1979 may be influenced by the limited number (5) of cruises.
As the largest phosphorus loading and the most complete data bases are from the western basin,
the reminder of this discussion will be directed at that basin.
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Heterotrophic bacterial populations have been shown to be sensitive to minute changes in
nutrient concentrations and are thus sensitive indicators of nutrient changes (Godlewska and Lippowa
1976, Rao and Jurkovic 1977). Heterotrophic bacterial populations in the western basin increased from
an annual geometric mean of 478 organisms/100ml in 1978 to a geometric mean of 526 organism/lOOml
in 1979. The highest bacterial populations in both years were observed in the areas influenced by the
Detroit River, River Raisin, and Maumee River (stations 60, 61, 75, and 84). In 1978 the annual
geometric mean for the above stations was 1136 organisms/lOOml with a maximum observed population
of 21500 organisms/lOOml at station 60 during the October-November cruise. In 1979 the annual
geometric mean for these stations increased almost three times to 3150 organism/lOOml with a maximum
population of 115,000 organisms/lOOml observed at station 60 during the May cruise (#2). There were
three occurrences of populations >5000 organisms/lOOml in 1978 and seven in 1979 in this area (USEPA
- unpublished data). The increased bacterial activity observed in 1979 is in agreement with the larger
phytoplankton biomass and is suggestive of increased nutrient concentrations.
Unfortunately total phosphorus data is not available for a large portion of the 1978 study period.
However, during those periods for which data are available, western basin concentrations were higher in
1979. Total phosphorus concentrations from May through July averaged 18.8 ug/1 and 19.0 ug/1 in 1978
and 1979 respectively. This excludes the western basin mean of 98 ug/1 which was observed in April
1979, following severe storms. In 1979, a mean total phosphorus concentration of 29.3 ug/1 was observed
in the August through October period. While data is not available for this period in 1978, comparison of
the November cruises in each year suggests that total phosphorus concentrations in the later portion of
the 1979 season were as much as 50 percent higher than that observed in 1978. The mean western basin
total phosphorus concentration in November 1978 was 22.3 ug/1 compared to 32.7 ug/1 in 1979 (Fay and
Herdendorf 1981). Total phosphorus concentrations also increased from 1978 to 1979 in the central and
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eastern basins. During the periods for which data is available (May-November) total phosphorus in the
central basin averaged 8.4 ug/1 in 1978 and 12.1 ug/1 in 1978. In the eastern basin (May-August) total
phosphorus averaged 9.5 ug/1 in 1978 and 11.7 ug/1 in 1979 (Fay and Herdendorf 1981). The increase in
total phosphorus concentrations which occurred in 1979 supports, and probably contributed to, the
increased phytoplankton biomass.
It must be noted, however, that total phosphorus loads to the western basin decreased by 1075
metric tons (Yaksich and Melfi 1982) from 1978 to 1979. A period during which biological and chemical
data indicates that increased concentrations occurred, particularly in the western basin. Changes in lake
levels may be responsible for part of the concentration change. Water levels were 30 to 122mm below
1978 levels the first half of 1979, and 30 to 122mm above 1978 levels during the last six months of 1979.
As a result, the mean western basin volume for the two cruise seasons was relatively constant, averaging
24.41 Km3 in 1978 and 24.79 Km3 in 1979 (Fay and Herdendorf 1981). It is evident that while some of
the increase in total phosphorus concentration may be the result of complicated interactions between
loading and lake level, the majority must be explained by other mechanisms.
One possibility is that the increased loads of orthophosphorous (Table 9) in 1979 resulted in an
increase biologically available phosphorus despite the decrease in total phosphorus loading. The
bioavailability of the phosphorus from tributary loads ranges from 1 to 55 percent depending on the
contributing source of the phosphorus. Cowen and Lee (1976) reported that available phosphorus
comprised 5 percent or less of the total phosphorus in particulates in tributaries and from 1 to 24 percent
of the total phosphorus in urban run off to the Genessee River. Algal available phosphorus ranged from 0
to 50 percent (mean 22.7%) of the total particulate phosphorus in several tributaries to Lakes Erie and
Ontario (Maumee River, Sandusky-Honey Creek, Cuyahoga River, Cattaraugus Creek, Genessee River)
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(Martin et al 1982). If biologically available phosphorus comprised 13 percent or less of the total
tributary load to Lake Erie the 146 metric ton increase in the orthophosphorous load may have resulted
in an increase in biologically available phosphorus despite the decreased total phosphorus load.
That this may have occurred is suggested by the timing of the biomass increase, precipitation
events, and orthophosphate load in 1979 (Table 9). Precipitation was significantly above 1978 levels in
July, August, and November 1979. While Table 9 indicates that annual total phosphorus loads were
reduced in 1979, orthophosphorous loads were above 1978 levels from July through December 1979 with
the exception of October. In addition, during August and November 1979, total phosphorus loads
exceeded 1978 loads. Thus, probably not coincidently, total biomass increased dramatically from
mid-July to early August and remained high throughout the remainder of the 1979 season.
The results of the 1978-79 intensive study indicate that severe deterioration in water quality
occurred in the last half of the 1979 study. While chemical (phosphorus) data is lacking for a good
portion of 1978, the consensus of the data overwhelmingly indicates that deterioration in water quality
did occur. The increased phytoplankton biomass and bacterial activity in 1979 may have been a result of
the increased loads of bioavailable phosphorus that occurred in spite of the decrease in total phosphorus
loadings. Orthophosphorous loads to the western basin increased by 146 metric tons during the study,
from 3742 metric tons in 1978 to 3888 metric tons in 1979. The Detroit River contributed 116 metric
tons of this increase (Yaksich and Melfi 1982).
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The increase in orthophosphorous loading may have resulted from combined sewer overflows
and runoff due to the increased precipitation. Combined sewer, overflows from 25 major events
contributed 160 mt TP in the Detroit area (Giffels, Black, and Veatchs 1981) in 1979 (Table 9). This load
was estimated to be 50 mt above a normal rainfall year.
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References
Cowen, W. F. and G. F. Lee. 1976. Algal nutrient availability and limitation in Lake Ontario during
IFYGL. Part I. Available phosphorus in urban runoff and Lake Ontario tributary waters. USEPA
EPA600/3-76-094a. 217 p.
Fay, L.A. and C. E. Nerdendorf. 1981. Lake Erie water quality assessment of 1980 open lake
conditions and trends for the preceeding decade. CLEAR, Ohio State University. 161 p.
Giffels, L., J.R. Black and I.F. Veatch. 1981. Quantity and Quality of combined sewer overflows.
CS-806. Final Facilities Plan, Interim report. City of Detroit, Water and Sewage Department.
Martin, S.C., J.V. Depinto, and T.C. Young. 1982. Estimation of phosphorus availability for Great
Lakes tributary sediments using chemical and algal assay techniques. 25th Annual Meeting of the
International Association for Great Lakes Research. Abstract.
Munawar, M. 1981.Response of nannoplankton and net plankton- species to changing water quality
conditions. Canada Center for Inland Waters. 20 p.
Munawar, M. and I.F. Munawar. 1976. A lakewide study of phytoplankton biomass and it's species
composition in Lake Erie, April-December 1970. J. Fish Research Board, Canada 33: 581-600 pp.
Schelske, C.L., and E. Callender. 1970. Survey of phytoplankton productivity and nutrients in Lake
Michigan and Lake Superior. Proc. 13th Conf. Great Lakes Res., Int. Assoc. Great Lakes Res. 93-105 pp.
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Stoermer, E.F. and JJ. Yang. 1970. Distribution and relative abundance of dominant plankton
diatoms in Lake Michigan. Great Lakes Research Division, University of Michigan publication No. 16.
64 p.
Tarapchak, S. J. and E. F. Stoermer. 1976. Environmental status of the Lake Michigan region.
Vol. 4. Phytoplankton of Lake Michigan ANL/ES 40, Argonne National Laboratory. 211 p.
Yaksich, S.M., D.A. Melfi, D.A. Baker, and J.A. Kramer. 1982. Lake Erie nutrient loads 1970-1980.
25th Annual Meeting of the International Association for Great Lakes Research. Abstract.
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Table 1
Lake Erie Cruise Dates 1978 -1979
Cruise
Number 1978 1979
1 March 27-29
2 May 18-25 April 17-20
3 June 6-15 May 15-26
4 June 23 - July 2 sediments only
5 July 19-29 July 11-19
6 August 8-16 July 31-August 4
7 August 29- September 6 ship failure
8 October 3-12 September 11-21
9 October 24 - November 1 October 4-10
10 November 7-16 November 7-16
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Table 2
Seasonal Relative Abundance of Common (>5%)
Species in the Western Basin 1978
Cruise
May 18-25
June 6-15
June 23- July 2
July 19.-20
August 8-16
August 29 - September 6
Species
Melosira spp.
Tabellaria fenestrata
Closterium Lunula
Unidentified pennate diatom
Cryptomonas erosa
Cryptomonas ovata
Tabellaria fenestrata
Cosmarium spp.
Unidentified non-green flagellate
Rhodomonas minuta
Cryptomonas ovata
Cryptomonas erosa
Mougeotia spp.
Ceratium hinrundinella
Aphanizomenon flos-aquae
Ceratium hinrundinella
Cosmarium sp.
Aphanizomenon flos-aquae
Cryptomonas erosa
Cryptomonas ovata
Aphanizomenon flos-aquae
Coscinodiscus rothii
Melosira spp.
Coscinodiscus rothii
Aphanizomenon flos-aquae
Melosira spp.
Stephanodiscus niagarae
Oscillatoria spp.
Anabaena spp.
Percent of
Total Biovolume
34.43
16.28
15.11
7.57
32.74
12.63
9.20
7.16
6.11
5.41
14.57
12.89
12.84
10.03
7.30
53.79
11.99
7.99
7.11
6.07
49.50
14.38
11.88
28.62
14.13
11.58
9.28
6.58
5.14
eutrophic species
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Cruise
October 3-12
October 24 - November 1
November 7-16
Table 2 (Continued)
Species
Oscillatoria sp.
Melosira spp.
Coscinodiscus rothii
Anabaena spp.
Stephanodiscus niagarae
Pediastrum simplex
Oscillatoria spp.
Melosira spp.
Anabaena spp.
Mougeotia spp.
Oscillatoria spp.
Melosira spp.
Coscinodiscus rothii
Mougeotia spp.
Tabellaria fenestrata
Dinobryon spp.
Percent of
Total Biovolume
18.60
17.82
12.32
6.85
6.40
6.16
31.04
16.40
8.32
5.68
26.73
15.04
6.42
5.88
5.73
5.06
eutrophic species
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Table 3
Seasonal Relative Abundance of Common (>5%)
Species in the Western Basin -1979
Cruise
March 27-29
April 17-20
May 15-26
July 11-19
Species
Fragilaria spp.
Tabellaria fenestrata
Stephanodiscus niagarae
Melosira spp.
Stephanodiscus binderana
Unidentified Centric Diatom
Unidentified non-green flagellate
Diatoma tenue var. elongatum
Asterionella formosa
Fragilaria crotonensis
Melosira spp.
Diatoma tenue var. elonatum
Stephanodiscus binderana
Tabellaria fenestrata
Stephanodiscus niagarae
No data
Aphanizomenon flos-aquae
Ceratium hirundinella
Cryptomonas erosa
Coscinodiscus rothii
Cryptomonas ovata
Percent of
Total Biovolume
17.02
9.71
9.59
8.51
7.92
7.54
6.90
6.00
5.77
5.01
29.54
15.49
14.18
7.49
6.24
18.43
16.82
11.57
6.70
6.14
July 31-
August 4
Aphanizomenon flos-aquae
Coscinodiscus rothii
Anabaena spp.
Melosira spp.
Anabaena spiroides
23.10
19.48
9.95
8.18
7.49
eutrophic species
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Table 3 (Continued)
Cruise
September 11-21
September 4-10
October 7-16
Species
Melosira spp.
Stephanodiscus niagarae
Coscinodiscus rothii
Aphanizomenon flos-aquae
Anabaena spiroides
Anabaena spp.
Stephanodiscus niagarae
Melosira spp.
Aphanizomenon flos-aquae
Gyrosigma spp.
Pediastrum simplex
Stephanodiscus binderana
Melosira spp.
Stephanodiscus binderana
Stephanodiscus niagarae
Aphanizomenon flos-aquae
Diatoma tenue var. elongatum
Percent of
Total Biovolume
16.71
12.54
12.21
10.93
7.66
6.38
22.73
12.93
11.96
8.10
5.32
5.13
38.45
17.82
14.59
6.01
5.07
eutrophic species
Page -21-
-------
Table 4
Seasonal Relative Abundance of Common (>5%)
Species in the Central Basin 1978
Cruise
May 18-25
June 6-15
June 23 - July 2
July 19-29
August 8-16
Species
Asterionella formosa
Melosira spp.
Fragilaria crotonensis
Stephanodiscus niagarae
Stephanodiscus binderana
Unidentified non-green flagellate
Unidentified pennate diatom
Rhodomonas minuta
Tabellaria fenestrata
Cryptomonas erosa
Fragilaria crotonensis
Fragilaria crotonensis
Cryptomonas erosa
Unidentified non-green flagellate
Stephanodiscus niagarae
Rhodomonas minuta
Cryptomonas ovata
Tabellaria fenestrata
Ceratium hirundinella
Aphanizomenon flos-aquae
Stephanodiscus niagarae
Cosmarium spp.
Ceratium hirundinella
Aphanizomenon flos-aquae
Oedogonium spp.
Unidentified coccoid green
Scenedesmus bijuga
Percent of
Total Biovolume
31.92
18.08
6.44
6.40
6.39
27.95
13.06
9.48
8.70
8.54
7.25
15.72
11.42
12.21
9.64
8.32
7.32
6.77
29.34
8.00
7.59
5.10
21.93
13.30
9.61
5.49
5.13
eutrophic species
Page -22-
-------
Table 4 (Continued)
Cruise
August 29 -
September 6
October 3-12
October 24 -
November 1
November 7-16
Species
Oocystis borgei
Aphanizomenon flos-aquae
Unidentified coccoid green
Scenedesmus bijuga
Oocystis spp.
Oocystis pusilla
Stephanodiscus niagarae
Cryptomonas erosa
Aphanizomenon flos-aquae
Unidentified pennate diatom
Oocystsi borgei
Oocystis spp.
Cryptomonas erosa
Oscillatoria sp.
Cryptomonas ovata
Oocystis borgei
Stephandiscus niagarae
Unidentified coccoid green
Cryptomonas erosa
Cryptomona ovata
Oscillatoria spp.
Stephanodiscus niagarae
Percent of
Total Biovolume
17.68
11.53
8.79
8.79
7.60
5.75
12.53
6.56
5.81
5.71
5.60
5.22
13.85
11.44
9.74
7.80
6.55
5.53
17.10
12.21
11.79
6.22
eutrophic species
Page -23-
-------
Table 5
Seasonal Relative Abundance of Common (>5%)
Species in the Central Basin 1979
Cruise
March 27-29
April 17-20
May 15-26
July 11-19
July 31-
August 4
September 11-21
Percent of
Total Biovolume
36.03
10.81
8.89
7.59
7.32
Species
Stephanodiscus niagarae
Fragilaria spp.
Stephanodiscus binderana
Unidentified centric diatom
Gyrosigma spp.
No data
Stephanodiscus niagarae 15.55
Melosira spp. 12.29
Tabellaria Fenestrata 11.26
Diatoma tenue var. elongatum 10.65
Rhodomonas minuta 10.47
Unidentified non-green flagellate 7.09
Fragilaria crotonensis 5.99
Ceratium hirundinella 28.53
Coelastrum retic ulatum 14.67
Staurastrum paradoxum 7.21
Cryptomonas erosa 5.81
Rhodomonas minuta 5.53
Oocystis borgei 5.08
Represents only the western portion
of the basin
Ceratium hirundinella 25.30
Aphanizomenon flos-aquae 22.98
Fragilaria crotonensis 19.28
Coscinodiscus rothii 8.19
Stephanodiscus niagarae 28.05
Aphanizomenon flos-aquae 8.36
Pediastrum simplex 7.39
Ceratium hirundinella 7.28
eutrophic species
Page -24-
-------
Table 5 (Continued)
Cruise
October 4-10
November 7-16
Species
Stephanodiscus niagarae
Melosira spp.
Aphanizomenon flos-aquae
Melosira spp.
Stephanodiscus niagarae
Stephanodiscus binderana '
Percent of
Total Biovolume
30.63
18.40
8.23
41.76
29.97
14.69
eutrophic species
Page -25-
-------
Table 6
Seasonal Relative Abundance of Common (>5%)
Species in the Eastern Basin -1978
Cruise
May 18-25
June 6-15
June 23 - July 2
July 19-29
August 8-16
August 29 -
September 6
Species
Stephanodiscus binderana
Asterionella Formosa
Melosira spp.
Stephanodiscus niagarae
Fragilaria crotonensis
Unidentified pennate
Cryptomonas erosa
Tabellaria fenestrata
Closterium lunula
Cryptomonas erosa
Fragilaria crotonensis
Rhodomonus minuta
Unidentified flagellate
Asterionella formosa
Tabellaria fenestrata
Anabaena flos-aquae
Oocystsi borgei
Ceratium hirundinella
Staurastrum paradoxum
Cryptomonas ovata
Scenedesmus bijuga
Oocystis borgei
Ceratium hirundinella
Unidentified coccoid green
Oocystis borgei
Oocystis sp.
Scenedesmus bijuga
Unidentified coccoid green
Percent of
Total Biovolume
20.45
17.8
9.6
9.6
9.2
15.7
14.0
11.5
5.3
16.4
14.4
11.7
11.2
9.8
6.6
18.7
17.0
13.0
7.4
5.1
28.4
15.1
8.3
5.5
24.9
16.7
11.1
8.0
eutrophic species
Page -26-
-------
Table 6 (Continued)
Cruise
October 3-12
October 24 -
November 1
November 7-16
Species
Oocystis borgei
Oocystis sp.
Tabellaria fenestrata
Staurastrum paradoxum '
Unidentified coccoid green
Unidentified pennate
Tabellaria fenestrata
Stephanodiscus niagarae
Cryptomonas erosa
Oocystis borgei
Cryptomonas ovata
Staurastrum paradoxum
Cryptomonas erosa
Tabellaria fenestrata
Staurastrum paradoxum
Cryptomonas ovata
Cosmarium sp.
Percent of
Total Biovolume
13.9
11.1
10.4
8.6
6.3
5.8
21.9
14.7
13.3
7.2
7.0
5.1
18.1
15.2
12.8
10.6
5.2
eutrophic species
Page -27-
-------
Table 7
Seasonal Relative Abundance of Common (>5%)
Species in the Eastern Basin -1979
Cruise
March 27-29
April 17-20
May 15-26
July 11-19
July 31-
August 4
September 11-12
October 4-10
Species
Stephanodiscus niagarae
Unidentified Centric Diatom
No Data
No Data
Oocystis borgei
Ceratium hinrundinella
Rhodomonas minuta
Fragilaria crotonensis
Cryptomona erosa
No Data
Ceratium hirundinella
Staurastrum paradoxum
Oocystsi spp.
Cosmarium spp.
Coelastrum microporum
Stephanodiscus niagarae
Ceratium hirundinella
Microcystis aeruginosa
Staurastrum paradoxum
Percent of
Total Biovolume
78.33
8.17
19.31
17.49
11.06
7.30
5.70
27.78
10.02
8.72
7.50
6.78
35.73
10.54
10.49
5.02
November 7-16
Stephanodiscus niagarae
Cryptomonas erosa
66.87
5.24
eutrophic species
Page -28-
-------
Table 8
Mean Epilimnetic Biomass in the Western Basin1 of Lake Erie (mg/1)
July - November 1970,21978,1979
1970 5.18
1978 2.48
1979 7.70 (4.91)3
1) 1978 and 1979 mean for stations 50, 51, 55, 58 and 61 which correspond to those surveyed in
1970.
2) 1970 data from Munawar and Munawar 1976.
3) Mean biomass not including the large bloom observed on the November 11, 1979 cruise.
Page-29-
-------
Table 9
Mean Monthly Precipitation at Toledo, Ohio and
Tributary Phosphorus Load to the Western Basin
Precipitation (inches)
Difference
Month
January
February
March
April
May
June
July
August
September
October
November
December
1978
3.14
0.54
2.34
3.74
2.48
5.34
1.86
1.67
3.19
1.65
2.48
3.31
1979
1.24
0.70
2.55
4.03
3.15
4.23
3.96
4.71
2.90
2.02
4.25
2.46
30 year
(1979-1978
-1.90
0.16
0.21
0.29
0.67
-1.11
2.10
3.04
-0.29
0.37
1.77
-0.85
Normal
2.08
1.75
2.52
2.95
3.33
3.38
3.23
3.07
2.40
2.24
2.32
2.24
Month
Tributary Phosphorus Loads (Metric Tons)
to the Western Basin
Total Phosphorus
1978 1979
January
February
March
April
May
June
July
August
September
October
November
December
562
474
2099
1605
679
573
588
517
506
527
514
506
496
411
1245
1279
642
468
530
584
438
434
626
982
Orthophosphorous
1978
255
210
676
580
315
254
266
231
228
239
233
255
1979
259
225
522
539
315
251
284
304
234
235
301
414
Page -30-
-------
Figure 1
NEW YORK
CLEVELAND
PENNSYLVANIA
OHIO
FIGURE 1
SAMPLING LOCATIONS
1978
Page-31-
-------
Figure 2
NEW YORK
CLEVELAND
PENNSYLVANIA
OHIO
FIGURE 2
SAMPLING LOCATIONS
1979
Page -32-
-------
Figure 3
Seasonal Fluctuation in Total Phytoplankton Biomass
in the Western Basin of Lake Erie in -1978
S
r*
"r*.
Jr
IG.o
is.fl
T4.0
13-0
12.0
n,o
IO.O
9.fl
DJO
3.O
2.D
u
a
j^t I Fab ~"[~tf or I A>»» | May | Jime j jjtj T| ftun
Pel
Page -33-
-------
Figure 4
Seasonal Fluctuation in the Major Group Composition
of the Phytoplankton in the Western Basin in 1978
Cyanophyta
, Chlorophyta
Diatomeae
Cryptomonadinae
Dinophycinae
Unidentified Flagellate
Page -34-
-------
Figure 5
Seasonal Variation in the Diatomeae, Chlorophyta,
and Cyanophyta in the Western Basin -1978
*.*
i.eo
gCI'T | QCT | MOV l| PEC
Page -35-
-------
Figure 6
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Western Basin -1978
4.0
IAPR I MAY TJuNE | ju~v| "Joi [septIOCT I NOW DEC
C hrysomorMHl iJiiva « * mm u m
Page -36-
-------
Figure 7
Seasonal Fluctuation in the Total Phytoplankton
Biomass in the Central Basin of Lake Erie in -1978
o
03
17.0
16.0
15.0
14.0
13.0
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Jan I Feb
Mar I April | May
June I July
Aug Sep Oct Nov {Dec
Page -37-
-------
Figure 8
Seasonal Fluctuation in the Major Group Composition
of the Phytoplankton in the Central Basin in 1978
100 B
JAN FEB MAR APB MAY
Cyanophyta
Chlorophyta
Diatomeae
Cryptomonadinae
Dinophycinae
Unidentified Flagellate
Page -38-
-------
Figure 9
Seasonal Variation in the Diatomeae, Chlorophyta,
and Cyanophyta in the Central Basin -1978
2.4
I
s
1.60
1.5O
1.4O
30
1.2O
1.10
1.OO
0.90
O.80
0.70
O.60
O.BO
0.40
O.3O
O.20
0.10
O.OO
JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC
Cyanophyta
Chlorophyta
Diatomeae ^jt
Page -39-
-------
Figure 10
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Central Basin -1978
1.6O
1.SO
1.40
1.30
1-.2O
1.10
1.OO
O.9O
0.8O
S 0.70
0.30
O.20
O.1O
O.OO
JAN FEB 1 MAR APR 1 MAY JUNE JULY AUG SEPT OCT NOV DEC
Dinophycinae
Chrysomonadinae !
Cryptomonadinae v^^'W.'ur'
Page -40-
-------
Figure 11
Seasonal Fluctuation in the Total Phytoplankton
Biomass in the Eastern Basin of Lake Erie in 1978
E
o
2
17.0
15.0
15.0
14.0
13.0
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Jan Feb Mar April I May June July Augl Sep Oct | New [ Dec
Page-41-
-------
Figure 12
Seasonal Fluctuation in the Major Group Composition
of the Phytoplankton in the Eastern Basin in -1978
1 1 1 ^r,p»rrn^i
FEO I M1AR | ARH | J.
-------
Figure 13
Seasonal Variation in the Diatomeae, Chlorophyta, and
Cyanophyta in the Eastern Basin 1978
1.8
r
x,
o>
1.6O
1.50
1.4O
1.30
1.20
1.10
1.OO
0.30
O.8O
5 0.70
O.6O
O.5O
0.40
O.30
O.2O
O.1O
0.00
JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT | NOV DEC
Cyanophyta mmmaaBffmaaBmm
Chlorophyta
Diatomeae jrjr*r*r*'*rJ
Page -43-
-------
Figure 14
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Eastern Basin -1978
1.6O
1.5O
1.40
1.3O
1.20
1.1O
1.OO
" 0.90
en
« 0.8O
(0
6
.2 0.70
CO
0.6O
0.50
O.40
0.30
0.20
O.10
0.00
_
_
_
_
_
- . "~~
; A ^_ ;
JAN | FEB | MAP | APR j MAY JJUNE | JULYJ AUG | SEPT | OCT | NOV | DEC
Dinophycinae
Chrysomonadinae
Cryptomonadinae rjrjr^rjrjrjrjr
Page -44-
-------
Figure 15
Seasonal Fluctuation in the Total Phytoplankton Biomass'
in the Western Basin of Lake Erie in -1979
y,
n
o
m
Q.
a
17.0,
I
16,0
15.0
14.0
13.0.1
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4,0
3.0
2.0
1.0
0.0
Jan
Feb
Mir
April
Msy |June | July | Aup | Sep
Del | Nov
Die
Page-45-
-------
Figure 16
Seasonal Fluctuation in the Major Group Composition of
the Phytoplankton in the Western Basin in -1979
Diatomeae
Cryptomonadinae
Dinophycinae
Unidentified Flagellate
Page -46-
-------
Figure 17
Seasonal Fluctuation in the Diatomeae, Chlorophyta,
and Cyanophyta in the Western Basin -1979
2.O6
1.60
1.50
1.4O
1.3O
1.20
1.1O
1.OO
O.90
0.80
9 0.70
CO
O.6O
o.so
O.4O
0.3O
0.20
^
O)
JAN | FEB 1 MAR | APR | MAY JJUNE | JULYJ AUG | SEPT | OCT | NOV | DEC
Cyanophyta i
Chlorophyta
Diatomeae ^^jr^^jr^r*^
Page -47-
-------
Figure 18
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Western Basin -1979
1.5O
1.4O
1.30
1.20
1.10
1.OQ
O.90
O.6O
O.5O
O.1O
0.30
0.2O
O.1O
JAN FED MAR APR I MAY JUNE JULY AUG SEPT OCT NOy DEC
Dinophycinae
Chrysomonadinae !
Cryptomonadinae jr**rjr^*r^jr
Page -48-
-------
Figure 19
Seasonal Fluctuation in the Total Phytoplankton Biomass
in the Central Basin of Lake Erie in -1979
^o
5
\Jan Feb Mar 1 April May June July Aug 1 Sep dot I Nov Dec
0.0
Page -49-
-------
Figure 20
Seasonal Fluctuation in the Major Group Composition
of the Phytoplankton in the Central Basin in -1979
JAM 1 FEB ! MAW 1 APR I MAY lJUNE [JULY
Cyanophyta
i
Chlorophyta
Diatomeae
Cryptomonadinae
Dinophycinae
Unidentified Flagellate
Page -50-
-------
E
o
1.00
i.so
1.4Q
1.30
1.20
1.10
1.OO
0.90
0.60
O.50
O.4O
O.3O
O.20
o.io
0.00
Figure 21
Seasonal Variation in the Diatomeae, Chlorophyta,
and Cyanophyta in the Central Basin -1979
2.1
\
22 X
i
,X'7
.6
I J 'tf
% / S,
JAN FEB
MAV I JUN£ | JUtr
SEPT OCT IOOV
Cynnophyta
Diatornooo ^&^if*r4f!*K4r*t*r
Page-51-
-------
Figure 22
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Central Basin -1979
FED I MAR I APft MAY IJUNE I JULY | AUG
O.OO
Dinophycinae
ChrysomonBdinae
Page -52-
-------
Figure 23
Seasonal Fluctuation in the total Phytoplankton Biomass
in the Eastern Basin of Lake Erie in -1979
o
S
17.0
16.0
15.0
14.0
12.UB-
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Jan Feb Mar April I May |June | July | Aujj
Sep
Oct
Nov
Dec
Page -53-
-------
Figure 24
Seasonal Fluctuation in the Major Group Composition of
the Phytoplankton in the Eastern Basin in 1979
JAN j FEE | MAR I APR I MAY I.JUNE
Cyanophyta
i
Chlorophyta
Diatomeae
Cryptomonadinae
Dinophycinae
Unidentified Flagellate
Page -54-
-------
Figure 25
Seasonal Variation in the Diatomeae. Chlorophyta,
and Cyanophyta in the Eastern Basin -1979
E
-^
en
O
£
JAN I FEB |"MAR | APR | MAY [JUNE | JULY AUG | SEPT | OCT | MOV | DEC
0.20
0.10
Cyanophyta
Clorophyta «
Diatomeae ^i*o*o*ur^ur^o«c<
Page -55-
-------
Figure 26
Seasonal Variation in the Dinophycinae, Chrysomonadinae,
and Cryptomonadinae in the Eastern Basin -1979
**.
o>
v&o
1.BO
1.4O
1.3O
5 20
1.10
1.OO
O.9O
°-BO
ra
S 0.70
tt>
O.6O
O.5O
o.*o
O.3O
O.2O
0.1O
000
JAN I FEB | MAR \ APR. [ MAY
JULVl AUO
[ 5EPT I DCT I NOVJ PEC
DmopKycinae
Chrysomonadlrieo *
Cryptomonadlnae "fjfjffjtrjf^f^
Page -56-
-------
Figure 27
Seasonal Variation in the Horizontal Distribution of Total Phytoplankton Biomass in the
Epilimnetic Waters of Lake Erie -1978
- *».-
r^
fj "=" » *.-...
_/*3 .-,-. '* '"".V-.'.^r
/A-j
Seasonal Variation
in the Horizontal Distribution
of Total Phytoplankton Biomass
in the Epilimnetic Waters
of Lake Erie-1978
Data represents means for e)l samples
(rom 1-15 meters.
Sample date is cruise midpoint.
g/m>
< 2 2-S 5-1O 1O-2O >2O
Page -57-
-------
Figure 28
Seasonal Variation in the Horizontal Distribution of Total Phytoplankton Biomass -1979
" "/ ' c......
t . -o~1
'"
-
* ; f'**?1!!
f i__ ' MwiuriwA*;*
Seasonal Variation
In the Horizontal Distribution
of Total Phytoplankton Biomass -1979
Data represents means (or all samples
from 1-15 meters.
Sample date is cruise midpoint.
© ^^
<2 2-5 5-10 10-20 >20
Page -58-
-------
Figure 29
Mean Epilimnetic Biomass in the Western Basin
of Lake Erie in 1970,1978 and 1979
IB.ao
i.eo
t.so
1.40
1-3O
1,80
1.10
l.OO
* O.90
E
"x,
en
« O.DQ
O ^ -a«
i O.7O
OB
O.60
Q.SO
o.«o
O.3O
0.20
O.1O
O DO
\
\
\
\
\
- s
s
s
- V
s
S
%
~ ^
;
i S
5
% s »
5 i ^ «
J ? < 3
F I
js 5 5 i^i
~ i i JM'I1 M
JAN 1 FEB j MAR j APR | MAY j JUNE | JULY |
"~~
g .
v
i :
H m
s » *» ~
k m \
i 8 S
\ ^
x. ? S
W " ? N
5 54 S
^ -5 ^
Ullr
1 iu il I r
AUG SEPT | OCT | NOV DEC
1.970 v^^*nnrjr***Mnr.
1978 BBMMBBBBMBHBHBBM
1979 ittmmttmmmmmmmmm
1976-79 M«M» *r« colculitod uting
«t»tion» 50.51, 55. E8, *nd 61 which
f*pr*i«ni tUniEnr Qtoeraptlte erens
fo Mh*t sampled In 197O.
197D DpIB from Mtlrfl»w»r and MunBW»r, 1976.
Page -59-
------- |