Environmental Protection
Agency
Research and Developmen
Gulf BVeeze FL 32561
Middle Atlantic Region 3
6th and Walnut Sts
Philadelphia PA 19106
Chesapeake Bay Program
EPA 600/8-80-040
JUNE 1980
BIOSTRATIGRAPHY OF CHESAPEAKE BAY
AND ITS TRIBUTARIES
A Feasibility Study
Mill
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EPA 600/8-80-040
JUNE 1980
BIOSTRATIGRAPHY OF CHESAPEAKE SAY
AND ITS TRIBUTARIES
A Feasibility Study.
by
Grace S. Brush, Frank W. Davis, and Sherri Rumer,
Department of Geography and Environmental Engineering
The Johns Hopkins University
Baltimore, Maryland 21218
Grant Number R 805962
Thomas Nugent, Project Officer
Chesapeake Bay Program
U. S. Environmental Protection Agency.
Mid-Atlantic Region III
and
Office of Research and Developent
2083 West Street
Annapolis, Maryland 21401
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports.
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U.S. ENVIRONMENTAL PROTECTION AGENCY
CHESAPEAKE BAY PROGRAM .
In response to Congressional directive, the U.S. Environmental Protection
Agency established the Chesapeake Bay Program (CBP) to conduct an in-
depth study of the Chesapeake Bay and its resources. The Program was
initiated in 1976 as a five-year, $25,000,000 program to conduct
interdependent scientific and management investigations addressing the
environmental quality of the Chesapeake Bay. Major responsibilities
are defined as follows:
p to assess the principal factors having adverse environmental impact,.
o to direct and coordinate research and abatement programs,
o to collect research data and institute a monitoring program, and
o to define Bay management structures
Within EPA, the Chesapeake Bay Program is a coordinated effort between
the Office of Research and Development and the Mid-Atlantic Region III
Office and is administered from a field station in Annapolis, Maryland.
Initial CBP efforts established strong working relationships with the
Bay area States, the scientific community and the citizenry. The Program
involves active participation from Maryland, Virginia, Pennsylvania and
Bay region citizens.
Programs are underway to research toxic substances, submerged aquatic
vegetation (SAV), eutrophication (excessive enrichment), and environmental
management. To support all Program efforts, including the interpretation
of data, computer modeling, and long-term data storage and retrieval
a data management system capable of meeting CBP needs is being developed.
The products of the four program areas will provide important tools
aiding in defining management alternatives to improve the environmental
quality of the Chesapeake Bay. Citizens, managers, scientists and Bay
users will all input to the development of alternative control strategies.
The coordinated efforts of the Chesapeake Bay Program provides a founda-
tion of interdependent scientific and management criterion important to
managing the environmental health of the Chesapeake Bay.
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DISCLAIMER
This report has been reviewed by the Chesapeake Bay Program, 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
.A major objective of the Chesapeake Bay Program submerged aquatic
vegetation study is to ascertain if a decline in baygrass populations has
occurred over time and if natural population cycles can be identified.
The biostratigraphic technique may represent a tool by which submerged
aquatic seeds can be detected in bottom cores and through presence/absence
seed analysis, aquatic plant cycles identified. '! • /
This project was conducted to demonstrate the feasibility of this
approach and to develop preliminary information concerning the historical
trends of aquatic grass populations in the Chesapeake Bay.
iii ; :;;
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ABSTRACT : ;
Seeds of submerged aquatic vegetation (SAV), diatoms and poll-en of ter-
restrial plants, extracted from sedimentary cores 1 to 1.4m long in -estuarine
tributaries, yield information regarding changes in SAV populations, eutro-
phication and sedimentation since European settlement.
Eeres taken from undisturbed depositional areas represent regional con-
ditions wsrth^ejSjpjeerfb^^^ , because di atoms and
pollen are affected by estuarine transport processes in such a manner that
>OGafc^atcMiiess^tsseKas^^ Ver-
t4§£jJihi;S*0rica3^^
described d'-ofeaywhofl^^ because the data from one
sample at a locale is representative of the whole locale.
§AV«seeds, however, are not transported as far because they are
Hence their s^a£4afadis*r4tofftTOns^
;to^^^ In reconstructing the
history of SAV, this requires that a few locales where environmental changes
are well documented be studied in detail, thus allowing ge^er^l^^afet-oiw^tbCHijb
toe^fifectson35$V^popu3?atTO^
MVsseedis extracted from cores in the €ppejfeBay, even though highly vari-
able, eensiifStent^yrrefilee^^
and show mago^obaTiges^w^poprta^ofls^of^^
meat. .,.•••• . •• - • .. , •.••--;
of terrestrial plants extracted from 12 cores in
and one from the Bayqrcopev indicate that sedsmenitaMofe^a^eswVra*^ from
apd vaT^^-ith^^^eoTse^rom^t^Cfflyfr^^^ in.dicatinga
This vaT'tabaMtyrappeaFS^ is i
^Diatoms extracted from cores in the g~orgafl4c^-14y
^i nGreased=4romM;he«?826=^sto^tieKpresent , ref lecti rig the i n'f 1 u-
ence of increased human occupation of the watershed on the aquatic environment.
IV
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. CONTENTS . . . ./ . ; _, V. •'
Foreword...... ......................................'. iii
Abstract... , iv
Figures. vi
Tables ? :'..'..... ix
Acknowledgments x
1. Introduction and Objectives......... .^.>......................... 1
2. Conclusions and Discussion................../.,..;............... 4
3. Study Area .................;.......... 7
Description ;.. •'.......................'. 7
Hi story .........;;... 11
4. Submerged Aquatic Vegetation.... ......v..i............ 20
Introduction 20
The SAV Fossil Record.. 21
Distibutions of Seeds in Sediments.. 24
SAV Biostratigraphy of Upper Chesapeake Bay;'...-:;.; 35
5. Sediment Transport and Deposition. .......,.........*... 53
Introduction ..i............... ^. 53
Spatial Distributions of Pollen in Estuarine Sediments..... 54
Vertical Distributions of Pollen in Estuarine Sediments 72
6. Eutrophication .^ 79
Introduction 79
Methods •.'.'•'. 79
Resul ts 81
7. References 90
Appendix ; 96
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FIGURES
Number • Page
1" Location of study area .......................;.. 8
2 Locations of cores taken in Susquehanna Flats.. 9
3 Locations of cores taken in Furnace Bay...........;........;.».. 10
4 The Susquehanna River drainage basin......................... ^.. 12
5 Reported lumber production in Pennsylvania for selected years... 15
6 An example of the SAV fossil record 23
7 Locations of surface sediment transects in Leeds Creek*......... 25
8 Seed concentrations of ZanichelHa palustris in surface sedi-
ments of Leeds Creek .-....'-.-. •..<..........-'. 27
9 Seed concentrations of Ruppia maritima in surface sediments of
Leeds Creek. ...-....... *....... 28
10 Seed concentrations of Potamogeton peotinat-us in surface sedi-
ments of Leeds Creek .... 29
11 Upper Chesapeake Bay cores showing levels analyzed for SAV
seeds .......:..*....:..... 36
'12 Seed concentration of Vallisneria americdna in cores from
'Susquehanna Flats ....*'.................... 37
13 Seed concentrations of Najas flexiUs in cores from Susquehanna
Flats 38
14 Seed concentrations of Elodea canadensis in cores from
Susquehanna Flats........ ........*.. 39
15 Seed concentrations of Potamogeton spp. in cores from ;<
Susquehanna Flats 40
16 Seed concentrations of Myriophyllwn spiaatwn in cores from :
Susquehanna Flats.. 41
" 17 -.... Seed flux of Vallisneria amerioana in cores from Furnace Bay.... _44
-•• • . > . (Continued)
''•'
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FIGURES (Continued)-, .
Number • . . ., . .'""..!.'.'. Page
18 Seed flux of Najas spp. in cores from Furnace Bay................ 45
19 Seed flux of Elodea canadensis in cores from Furnace Bay........ 46 '''.
20 -Seed flux of Potcanogeton spp. in cores from .Furnace"Bay....... ..47
21 Seed concentrations of Myriophyllum sp-icatum in cores from
Furnace Bay 48
22 Locations of surface sediment transects for. pollen distributions _
in the Potomac River and locations of quadrangles used; as the .:'..'
vegetati on source for the pol 1 en..:.....................'..............". .56
23 Distributions of pollen types in surfacesediments throughout^
the tidal stretch of the Potomac River denotes channel samples.. 57
24a Percent pine of total basal area, in vegetation versus lati-
tudinal and longitudinal distance with .95 percent confidence '
intervals ..........:... 68
24b Percent pine of total pollen in channel samples versus distance
downstream .,....'.................... 68 .
25a Percent sweet gum of total bas^al area^ iri vegetation^y.ersus
latitudinal distance with 95 percent confidence intervals.,...... 69
25b Percent sweet gum of total pollen in channel saitiples versus , ;
distance downstream........;,.... .-.,.•,'••.. ....>......;............:. 69
26 Stratigraphic pollen profile of Core I from FurnaceBay and.the : < '
flux of pollen of oak, ragweed, pine and'hemlockV.'................... 73
27 Stratigraphic pollen profile of Core II from Furnace Bay and
the flux of pollen of oak, ragweed, pine and hemlock............ 75
28 Stratigraphic. profile of the total number of genera and species
of diatoms in cores from Furnace Bay and Susquehanna Flats...... 80
29 Stratigraphic profiles of total diatoms and total .numbers and
percent of total diatoms of Aclvvanthes*.Coccpnei,s3. Cymbella,
Gomphonema, Naviaula and Nitzschia in cores from Furnace Bay,... 82
30 Stratigraphic profile of total diatoms, and total, numbers and . ;
percent of total diatoms of Coscinodiscus; Cy.ctetella>..EwT0tia3 ..'.""'••
Epifhemia, Fragitaria and Synedra in cores from Furnace Bay...../ 83.
(Continued)
vn
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FIGURES (Continued)
Number ' . Page
31 Stratigraphic profiles of total diatoms and total numbers and
percent of total diatoms of Achnahthes, 'Coeconets, Cynibella,
Gomphonema, Navicula and NitzscHia in'cores from Susquehanna
Fl ats ;.....; 84
32 Stratigraphic profiles of total diatoms and total numbers and
percent of total diatoms of Coscinodiscus, Cyclotella, Eunotia3
Epithemia, Fragilaria and Synedra in cores from Susquehanna
Flats .... 85
vm
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ACKNOWLEDGMENTS
Dr. Owen Bricker and Robert M. Summers assisted us in collecting the
sedimentary cores. Ed Schiemer helped to improvise the coring device for
estuarine sediments. Richard Maldeis provided us with vegetation data from
Leeds Creek and also contributed to field work in Eastern Bay. Peter Christie
assisted in seed identifications, particularly in the Leeds Creek Study.
James Stasz assisted in diatom extraction, identification and enumeration.
We thank Dr. Ruth Patrick for inviting one of us (SR) to her laboratory
for a short course in diatom taxonomy and ecology.
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•'. TABLES :.••'•"•"• . .-•
Number . . '; : ' Page
1 Agricultural Statistics for Selected Years in the Southern
Susquehanna River Basin............,......;....... 11
2 Production of Pennsylvania Anthracite for Selected Years....... 16
3 SAV Seeds and Pollen in the Stratigraphic Record.•'..-...i .... 22
4 . .SAV Seed Concentrations in Leeds Creek Surface Sediments....... 30
5 Analysis, of Leeds Creek SAV Seed Concentrations using
Krus'kaT-WalTis Nprtparametric test.......'..:.....'..^............ 32
6 . Number of Samples Required for Estimating Mean SAV Seed
Concentrations.... 33
7 Results of the 1978 Leeds Creek SAV Survey... ....... .i.;.... 34
8 Percent bf Total Tree Pollen in Channel Samples and Percent of
'Total Basal Area of frees > 0.001 Percent in Designated Source
Area 59
9 Percent of Total Pollen of All Shrub and Herbaceous Types. 60
10 Matrix of Index of Similarity in Percent pf Pollen in Surface
Sediments from the Potomac River..............*....... 61
11 Degression of Percent of Total Pollen in the Surface Sediments
on Distance Downstream in Nautical Miles... 64
12 Regression of Mean Basal Areas in Latitudinal and Longitudinal
Section in the Vegetation on Distance of Section from North to
South or West to East in Miles • 65
13 Mean Total Basa] Areas and Mean Percent Basal Areas in the
•Vegetation.....7................................. .....•* 66
14 Summary of Sedimentation Rates Based on Palynological Indica-
tors Thus Far Obtained for Chesapeake Bay and Tributaries 78
15 .Summary of Stratigraphic Data on Diatom Zones in Cores from
Furnace Bay and Susquehanna Flats 86
IX
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SECTION 1_
INTRODUCTION AND OBJECTIVES.
INTRODUCTION
The vegetation occupying a watershed,, its-land.use, and the transport
and rate of sediment deposition have an important influence on the biological
and chemical composition of the receiving water, body, determining in large
measure the amount and frequency of runoff, chemical and nutrient input and
turbidity. Any assessment of the effects of .current land.use, runoff and
sedimentation is difficult to evaluate without
There are very {faewshi-s^or4ca^sda*a , unfortunately, that can be used for
such comparative studies. Even where biological and chemical parameters have
been monitored, standard procedures have not been used in all cases; cover- .
age has been limited to a few specific problem areas and in -very few instan-
ces have the data been collected for more than a decade. Even where the
records are reasonably complete for a particular tributary, the information
cannot be generalized to all other tributaries .because the soils and drain-
;age of the watershed and the morphometry of the tributary are specific to
the tributary and its watershed. Very few tributaries are sufficiently simi-
lar so that interpretations based upon data collected from one can be applied
to others, much less to the main stem of the Bay. :
\ Nevertheless, a eompHation^l^cfra^^^
• the^oOTgysrandachem^sl^ woul d pro-
vide an ev;emW^4ew^jf~the:^f4eetfeof^^
and would indicate whether present conditions are unique, a repetition of
jrecurrent conditions or are continuous with the past.
: Although historical records are not adequate for such an evaluation,
the s-trAbag^apfltG^qnethorcb can be used to provide such a data base. The
stratigraphic method is valuable also because the sediments can extend the
; record beyond the time of human settlement so that it is possible to eorapbajse
|Ccmdit4oj«^i^4;43e^aquato^ of
ithe watershed. •,
I ' j. .' .-,- .. ...•;..-...• .-.,,. .- . '' '
' The stratigraphic method should be feasible for compiling long histor-
iical records of the Chesapeake Bay because the Bay and its tributaries are
'depositional basins in which are entrapped and preserved some aquatic organ-
: isms (e.g., diatoms, cladocerans), parts of organisms • (.e»g., sponge spicules,
pollen and seeds of terrestrial and aquatic plants) and metabolic products ...._
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of organisms (e.g., chlorophyll degradation products, amino acids). These
fossil organisms and remains of organisms represent a portion of the estu-
arine biota at the time of deposition. Historical changes in the composition
of the biota as well as in biomass can be quantified by identifying and
enumerating the fossil remains. Thus dianges^M^^Pesence^n^bseiiee and
in the s^e^test^corapQs^tionjsef^u at different
stratigraphic horizons ^cesen^efeawpsc^B^
(SAV) at the time of deposition. Similarly,
where preserved can yield
and hence are po$eflt^a&4fid
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This study was undertaken to investigate thVfeasib.il ity of the strati-,
graphic method for describing-changes in SAV, eutrophication ar\d sedimenta-
tion rates in the Chesapeake Bay estuary over long periods of time.
OBJECTIVES --: ••'
i jne objectives of the study were:
1. to vdeivttfy the organisms and parts or products of organisms that
are the besfcf;0ss;3:fc3:nd.fefcto^ by observing which
fossils are present most consistently from cores taken in several tribu-
taries, and to idefAify^he^chaiig estate that would serve
shociizons ;
2 . to tfeteTTOwep^tvesriumber^
dataa by observing variations in spatial distributions in closely spaced
samples taken in surface sediments of the fossils chosen as indicators;
•-- 3 . to determine whether or not there are
'-, and
4. to deftCTe^e^eso3:U:tion=o^ttoe^
spati^sapea^sr-eppesentetbxby^aiscor-fe (or series of cores) taken at a location
by studying one area in some detail.
The manner in which each of these questions is addressed is described
in the following sections on Submerged Aquatic Vegetation, Sediment Trans-
port and Deposition Rates, and Eutrophication. Laboratory methods that are
the same as those described in the Quality Assurance report for this project
are not repeated here., However, methods which have been modified are
described in Appendix A.
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SECTION 2
"CONCLUSIONS AND DISCUSSIONS"
The record left by organisms and parts of organisms in estuarine sedi-
ments is sufficiently complete to provide adequate data for reconstructing
some of the chemical, physical and biological conditions of the estuary over
long time intervals. The fiossijtesusexteafcii^i^tore of these parameters must
be ctiosen^eavefari^ysain^teTms^oS their afe*^^^te=ppeser-we , thei r 55ITsT4-t4mi;tys
;t0™en;v4siy)ntneiJtafacl>ange, and tti5esknowfe^gercifethe=t»s^co3t)^. Once a particu-
lar indicator is chosen, §amp±mg^des35tfc,musi~take^fento-aceoti»t? the
and the
on its final distribution in the sediments.
teeattons must be selected also from areas of wwlJsifeijriietWepostfci^on) so that
.the historical record is not distorted by scouring, erosion and mixing, ;
including resuspension and bioturbation. ;
In this study we attempted to identify the fossil indicators and estab-
lish sampling designs to describe regional trends or changes over long time
periods in SAV, eutrophi cation and sedimentation rates. In order to accomp-
lish this objective, we used the Upper Chesapeake Bay as a study area because
lit has a diverse depositional environment, thereby allowing us to compare the
ibiostratigraphy of different depositional basins in the same area. \
: The
in order
The sediments also contain fos-
Isil indicators of othei^popufl'at^sas , e.g., species of sponges and carapaces
I of cladocerans. These populations can pw>Ad^esd:nfiOCTia^^)n^v«'thEapeg»r-d«3t© \
;«a^^%^an^^h^sbto^X)gy-20fcthe=w:atei^ A more detailed and complete history :
jean be compiled by studying fossils of a greater number of different popula- ,
itions. However, since the analysis of a sedimentary core is time-consuming,
I careful consideration should be given to the kind of information being sought
jand to the knowledge of the ecology of the organisms represented by the fos-
jsils. If nothing is known of the existing distributions and ecological j
| requirements of a particular organisms, it will be difficult to interpret j
I fossil distributions in terms of their response to environmental change
juntil their present day distributions, requirements and limitations are
I understood. , .
LAST LifiEi
OF TEX
faf^ that the
$es^a«y3^ Acorn-
parison of pollen distributions in surface sediments with distributions of
jtrees in a wi'de band adjacent to an estuary sampled for pollen suggest that.
' ' •'"'
_ _
; TFiATiGNS.
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estuarine processes disperse the pollen in the estuary to a greater or
lesser extent depending upon the settling velocities of the individual
grains. Es^aimie^repersTOns^enre
due to patchiness of tree distributions, uneveness of pollen production, etc.
that were not eliminated by atmospheric dispersion, but it cteesWjafcraask
<^ci0na^-d=i^p4:buMeflS"0&^:e§eifeafeiea. Since pollen behaves in water simi-
larly to particles with small Reynolds numbers such as silt and clay, results
suggest that fine-grained sediments are transported similarly within the
estuary. That is, sediments are not likely to move very far from their
source, except when and where conditions are extremely turbulent, such as
during intense storms and at the mouths of the tributaries. Consequently, in
most cases, it can be expected that s^raeni-aMon^AtHesaaj^
age^*ea:=and:dloeafcl:andriise-. Our data, though preliminary, substantiate this
expectation. The large degree of variation in sedimentation rates between
cores suggests that local sediment inputs are not homogenized into an even
deposition of sediment throughout a tributary. Within the cores we have
studied, sedimentation rates are much higher during agricultural periods in
tributaries with large drainage areas than in tributaries draining small
areas; in the latter, there is little fluctuation in rates.
The above observations are preliminary in that they are based upon data
from a total of 12 cores from five tributaries and one core from the Bay
proper. It is necessary to measure the rates in most of the major tribu-
taries in order to delineate the importance of all factors involved in the
transport and deposition of sediment in the estuary as precisely as possible.
The «imi:te;r^ysiflsve»^ cores taken in
indicates that waietequaMty^s^goveisned-'by
The settling velocities of diatoms are
such that it is unlikely the populations of the two areas are mixed. More
likely, they represent in situ populations which may have been transported
short distances within each area. Susquehanna Flats and Furnace Bay are
quite different from each other hydrologically. However, water chemistry in
both areas is probably influenced more by the character and use of the water-
shed and therefore may be similar in both places. The diatoms, which are
sensitive to water chemistry, appear to be responding predominantly to a more
regional pattern of water quality. Thus, we can expect to obtain historical
data representative of the effect of watershed use on regiona.1 water quality
by studying vertical diatom distributions in one or two cores from a good
depositional area.
The ddssim^^arttysbetween^veirtflXia^^nofii^ressofcSAV^seeds3"^ i-n-cores from
Susquehanna Flats and Furnace Bay as well as the va^at^Wl^bet-ween-eores
within each area recognizes the htgfedegKeesofKpatchi^ness characteristic of
SAV. SAV is represented best in the sediments by seeds. Because of their
size (1 to 3 mm) and low buoyancy, they usually are not transported far from
the parent beds. Since these beds can change position from year to year,
they are characterized by a temporal patchiness as well as spatial patchi-
ness. In contrast to diatoms and pollen, the variability that characterizes
SAV and the ineffectiveness of transport processes to.erase this local
variability requires that a few strategic locations, where specific impacts
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are documented clearly, be sampled intensively. Past regional conditions
can then be inferred from observations of changes in populations in a few
areas'that are. obtained from a sufficient number of samples that regional
changes can be separated from natural variability and local effects.
LA:
OF
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SECTIONS
STUDY AREA
extracted from
and FtmnaeeEBa$ (Figure 1). The decision was made to do a detailed study of
one area in order to determine the resolution of the information contained in
the sediments. After examining cores from all of the areas listed above, the
Susquehanna Flats-Furnace Bay area in the Upper Chesapeake Bay was chosen
because depositionally it comprises two entirely different zones: one an
undisturbed depositional basin and the other a zone characterized by scouring
and redeposition. This study was to determine whether the history of changes
in SAV, eutrophication, and sedimentation in the Susquehanna Flats and the ;
Upper Chesapeake Bay—where the depositional history is complicated by scour-
ing and redeposition—would be reflected accurately in a small embayment such
as Furnace Bay, where the sediments once deposited. remain essentially undis-
turbed
DESCRIPTION
The SM&queha-imarf3;a;bs is a broad shallow estuary of roughly 90''km2
located at the juncture of the Susquehanna River and Chesapeake Bay
(Figure 2).
i The average depth of water at mean low tide is 1.2 m. The Flats are
^influenced very little by the tide and receive a ter;g*^^es^a*epsf4-4Dw from
the Susquehanna River. Consequently, the water is essentially fresh except
during very dry periods. fH^boflows from the Susquehanna River during storms
result in ^]i^.43^^^^^^n^,^d^^^^Qs4M-Qn^f^^^me^&. Since the Flats
are dominated by the Susquehanna River, their history should reflect the
historical effects of events in the Susquehanna watershed or, at least some
part, on the water of the Upper Bay.
; €u«nacesBay is a small embayment on the northern edge of the Susquehanna
Flats and is fed by Principco Creek (Figure 3). Unlike the Susquehanna
Flats, it is an exc€lsteii;bz^epo;S3iteitj»aisba;S5TO with a substrate consisting
[entirely of silt and clay. It experiences minimal scouring and redeposition.
JThe eastern side of Furnace Bay's watershed is forested to a larger extent
jthan the western side which is cleared mostly for agriculture (Figure 3).
iThe water is uniformly shallow, never deeper than 2 m. Furnace Bay may be
•somewhat more enriched than Susquebanna Flats because of local sewage dis-
charge into Mill Creek and subsequently into Furnace Bay.
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CHESAPEAKE BAY
o 5 10 NAUTICAL MILES
Figure 1. Location of study area.
1 8
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FLATS
Figure 2. Locations of cores taken in Susquehanna Flats (map from Bayley et
al., unpublished manuscript). Broken lines represent MBHRL SAV
survey transects.
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FORESTS
SAND AND GRAVEL
Figure 3. Locations of cores taken in Furnace Bay. Areas with dashed lines
are forested and hatched areas are sand and gravel quarries.
10
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HISTORY
In this section, we present synopses of trends and events in the
Susquehanna River Basin and Furnace-Bay watershed which relate directly to
the stratigraphic records from Susquehanna Flats and Furnace Bay.
The Susquehanna River Basin
The Susquehanna River drains a 25,510 mi2 basin which extends well into
New York State (Figure 4). Despite its size, practically every acre of the
watershed has been altered at some point in the past 3 centuries to meet
demands for food, lumber, coal, residential and industrial space (Susquehanna
River Basin Study Coordinating Committee 1970).
The land-use history of the watershed is extremely complicated. The "
task of reconstructing that history has been simplified by focusing upon
major statewide trends in the lumber and anthracite coal industries. The
analysis of agriculture in the watershed emphasizes those counties in the
southern basin which are adjacent to the Susquehanna River (Table 1).
TABLE 1. AGRICULTURAL STATISTICS FOR SELECTED YEARS IN THE SOUTHERN
SUSQUEHANNA RIVER BASIN*
1844
18845
1925
1964
Acres of
improved landt
2,448,160
2,958,510
2,482,920
2,524,812
% of total area
51.3
61.9
52.0
52.9 . .
Acres i n
principal
.field cropst
. not available
1,266,010
1,195,570
13161,780
% of
total area
26.5
25.0
24.3
* Includes Federal Census data for Harford arid Cecil Counties, Maryland,
plus the following counties in Pennsylvania: Chester, Cumberland,
Dauphin, Juniata, Lancaster, Lebanon, Mifflin, Montour, Northumberland,
Perry, Snyder, Union and York.
t Includes total cropland, pastureland, orchardland, vineyards, etc.
t Corn, wheat and oats. .
§ Average of 1880 and 1890 census data. .
We have distinguished, for purposes of this study, the following major
periods and events which are described in the accompanying text.
11
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N
I PENNA. •
"Two".
BEGiN
LAST LiN
OF TEXT
f'igure 4, Th.e SusqueKanW River drainage basin.
_i FOR TABLES
M-AND (LLUS-
, TRATiO?\iS
-------
1. The Lumber Industry:
1700-1840 - Hardwood Lumbering in the Pennsylvania Piedmont for
cropland and charcoal.
1830-1860 - Peak production of white pine from West Branch and upper
watershed.
1869-1900 - Peak production of eastern hemlock in upper watershed.
1910-1930 - Decline of American chestnut in eastern Pennsylvania.
2. Anthracite Industry:
1803-1850 - Development of the industry.
1875-1885 - Beginning of coal particle deposition in Upper Bay
sediments.
1890-1915 - Peak production. — -— - - --- — —
1920-Present - Acid mine drainage in central-eastern watershed.
3. Agriculture:
1700-1760 - European occupation of southeastern Pennsylvania.
1760-1820 - Establishment of stable agricultural system.
1790-1820 - Rise of ragweed in Upper Bay pollen record.
1870-1890 - Peak number of farms and peak crop acreage in south-
eastern Pennsylvania. Farm abandonment, in the Upper
Basin.
I
1950-Present - Suburbanization of river watershed with modest
decrease in farmland.
4. Major Floods:
October 1786 March 1904 j
March 1846 \. March 1936 • \
March 1865 j May 1946 I
June 1889 j March 1964 ;
May 1894 ;' June 1972 \
March 1902 .J
13
-------
The Lumber Industry—
Lumbering in the state before 1700 matched the need for cropland. Indi-
ans and pioneer settlers typically girdled trees to clear one or several acres
for planting. Fires were occasionally set to drive out .game and to create
forage (Defebaugh 1907). • , .
Between 1700 and 1760, an expanding population of European immigrants
spread northward and westward from Philadelphia. The area into which they
migrated contained mixed deciduous forests (white oak, red oak, black oak,
chestnut, pignut hickory, and black walnut) interrupted by occasional stands
of yellow pine and, on steeper river banks, hemlock (Lemon 1972). During
this time, scattered sawmills sprang up as far west as the Susquehanna River
to provide lumber for developing towns and homesteads. During this period,
iron furnaces fired by hardwood charcoal consumed substantial tracts of for-
est.outside the towns and in rural areas (Bining 1938). Nonetheless, in
1760, large tracts of open forest still characterized most of the watershed.
During the next 40 years, existing farms and towns in the southern basin
expanded considerably. The valleys east of the Allegheny Mountains were set-
tled at densities of 20 to 40 persons per mi2 (Lemon 1972). Deforestation
for cropland, charcoal and lumber continued, but it was piecemeal and thus
difficult to assess.
Charcoal manufacturing declined quickly when charcoal was replaced by
coal and coke (c. 1840) as the fuel for blast furnaces (Bining 1938). By the
mid-19th century, much of the timberland of the. Piedmont valleys and flood-
plains was cleared for agriculture, and upland slopes were cut for fuel and
pasturage.
Softwood lumbering in the Middle and Upper Basin,, especially along the
West Branch of the Susquehanna, was systematic and devastatingly thorough
(Tonkin 1940). Between the late 18th century, when speculators first began
buying up tracts along the West Branch, and 1900, white pine and eastern
hemlock were harvested faster than they could regenerate on both sides, of the
Allegheny Mountains. Pine production declined steadily after reaching its.
peak during the 1850's. Hemlock grew scarce within another 40 years but not
before Pennsylvania had led the nation in lumber production for nearly two
decades (Steer 1948).
The demise of Pennsylvania's forests, which can be inferred from :
Figure 5, is reported by the state forester in the 1880 U.'S. Census:
"Merchantable pine has now almost disappeared fromthe State, ';
and the forests of hardwood have been replaced either by second
growth or have been so generally culled of their best trees that . . I
comparatively little valuable hardwood timber now remains. Large !
and valuable growths of hemlock, however, are still standing in •;
northwestern Pennsylvania." . !
The spread of the chestnut blight (Endothia papasitica) from an epicen-
ter near Philadelphia was so rapid that by 1930 nearly every tree in the
State was infected, and the majority of trees east of the Allegheny Mountains
14 ._. .„._ _
-------
YEAR
1940
920
1900
1880
I860
TOTAL
EASTERN
HEMLOCK
WHITE
PINE
AMERICAN
CHESTNUT
-\
IxlO9 bd.ft.
IxlO9 bd.ft. 5xl08 bd.ft. 5xl05 bd.ft,
d 1 umber production in Pennsylvania for selected years_(Stee.nJ.94.8U
-------
were dead. Infection rates of 77 percent in 1912 and 88 percent in 1913
were reported for 1,637 trees examined in the vicinity of Philadelphia
(Commonwealth of Pennsylvania 1915). Because infection rates were high in
the southeastern corner of Pennsylvania by 1910, it seems likely that «ekes-ir
nttfcpotten began declining at this time in the poll-en assemblages of the
Upper Bay and probably disappeared altogether by
The Anthracite Coal Industry— -
The anthracite coal industry in Pennsylvania was centered on deposits
in Lebanon, Dauphin, Schuylkill, Northumberland and Luzerne Counties — in
other words, the central eastern section of the Susquehanna watershed. From
its beginnings in the early 19th century to its peak and subsequent decline
in the early 20th century (Table 2), coal mining had prodound effects on the
culture and the landscape of this region. The urbanization of northeastern.
Pennsylvania accompanied anthracite output. Mining was also responsible for
"acidic streams, scarred landscapes, underground fires, land subsidence, and
abandoned mine buildings and breakers" (Susquehanna River Basin Study
Coordinating Committee 1970).
TABLE 2. PRODUCTION OF PENNSYLVANIA ANTHRACITE FOR CERTAIN SELECTED YEARS
(from Susquehanna River Basin Coordinating Committee 1970)
Year
1825
• 1837
•1859
1 1891
M917 ]
1923 ;
! 1933 .
I 1944
; 1960 !
; 1964
Production (million of tons)
0.04
1.2
10-1
50.7
99.6
93.3
49.5
63.7 j
18.8 ;
17.2 ;
The £mt+>pae*tes«i?ndtist-py is reflected in the sedamewtis of the Upper Bay.
a^t-i«4«s^oraa«a*e»some«bott42ons in the Susquehanna Flats sedi-
ments. They began accumulating sometime in the second half of the 19th
16
-------
century, probably around 1880 (S. Lintner, personal communication), thus
providing a dateable horizon in the sediments of the Susquehanna Flats.
Agriculture—
The earliest farms in Pennsylvania appeared over 300 years ago. It was
not until the 18th century, however, that settlers spread. out from the
Delaware River basin and .Philadelphia westward into Lancaster County. By
1760, settlers had occupied land east of the Susquehanna River at average
densities of 20 to 29 persons per mi2. The best farmlands west to Cumberland.
County were only slightly less populous. During the next 40 years, the occu-
pied lands were cleared for farmland and fuel and were connected by roads
and political institutions. Despite movements of persons westward towards
Ohio, the population densities east of the Alleghenies doubled between 1760
and 1800 (Lemon 1972).
Benjamin Latrobe's map of the Susquehanna River, the product of a
survey performed in 1801 between Columbia, Pennsylvania and Havre de Grace,
Maryland, provides a general impression of the extent of farmland along the
River. At that time, long reaches of river are still enclosed by dense
forest, but cropland dominates other stretches, particularly along the
approach to Columbia (for a summary description of the map, see Lintner,
unpublished manuscript).
Apparently, enough land was cleared in the southern Susquehanna water-
shed in the latter 18th century to promote the rise of Ambrosia (ragweed)
pollen in the pollen assemblage borne by the river. We have assigned rough
dates of ^790^nd^820 to the fci^s^appeaT'ane
in the pollen record of the Upper Bay.
Table 1 (shown previously) shows trends in the acres of improved land
in selected counties of the Susquehanna Basin since 1844 (U.S. Census 1844,
1884i 1924* 1964). These Census data suggest that the amount of improved
land is roughly the same now as it was in 1844. Land in crops, orchard,
pasture and other. improvements (i.e., improved land) peaked during the 1880's
and then declined gradually to approximately 2.5 million acres in 1920
(Johnson 1929). Seventy-five percent of the reduction between 1880 and 1920
is in. orchards, vineyards and pasturelands. The number of farms and the
average size of individual farms also drops appreciably during this time.
The late 19th and early 20th century was an era of widespread farm
abandonment throughout the Piedmont, largely due to soil exhaustion
(Trimble 1974, Craven 1926). Though there was abandonment in the upper
Susquehanna watershed, the farms of the Pennsylvania Piedmont were excep-
tionally stable. This stability was partly due to the unusually fertile
soils of the area and to its topography, as well as its proximity to major
marketplaces such as Philadelphia (James 1928). Corn, wheat, oats and hay
are the principal crops of the region much as they were during the early
years of agriculture in southeastern Pennsylvania (Lemon 1972).
Floods— •-.-•••
The dates of major floods in the basin since 1784, as recorded at a
gauging station at Harrisburg, Pennsylvania (70 miles from the mouth of the
17 ..._._ .....
-------
river), are listed on page 13. The six largest floods which have occurred
at Harrisburg since 1889 are those of June 1972, March 1936, June 1889, May
1894, March 1964 and May 1946 in order of decreasing intensity.
Furnace Bay Watershed
The name Furnace Bay refers to a furnace built by the Principio Iron
Company in 1724. This company operated one of the region's first iron works
on Principio Creek between 1724 and 1787 (Bining 1938).
Some of the local historical events which might have affected the bio-
stratigraphic record in Furnace Bay sediments are outlined below:
Pre-1900
1658 George Simcoe built a small farm on the western shore of
Furnace Bay. Other settlers probably established themselves
on Perry Point. Certainly some forest acreage was cleared
for crops (Johnston 1881).
1724 The Principio Furnace was completed, along with a grist mill
and housing for colliers and other employees. Large tracts
of hardwood must have been cut for charcoal to fuel the
furnace. Cropland was probably developed to provide food
for company employees (Miller 1949).
1750 Some plantation homes were established on Perry Point around
this time, notably the Thomas mansion.
1750-1900 During most of the 18th century, the principal source of
income for local inhabitants was trapping and fur trading.
These were generally replaced as an economic base by agri-
culture around the turn of the century. In particular, the
western shore of Furnace Bay was continuously planted in
corn, wheat, hay and other crops throughout the 19th century
(County Directors of Maryland 1956).
Post-1900
1918 The local population remained small and agriculturally based
until 1918, when an ammonium nitrate (explosives) plant was
built on Perry Point adjacent to Mill Creek. The construc-
tion included "water, sewer and stream underground conduits,
streets, railroads, large machinery installations, a village
of more than 300 houses and theatre" (County Directors of
Maryland 1956).
In 1922, the entire complex was converted to a U.S.
Veterans Hospital. Sewage from the facility, as well as
from a rapidly expanding population in Perryville, was (and
••-•- still is) discharged into Mill Creek, and was probably
18
-------
responsible for the substantial organic enrichment of Mill
Creek and Furnace Bay still evident today (Upper Chesapeake
Watershed Association 1970).
1952 Beginning in 1952, sand and gravel were excavated from four
locations in the Furnace Bay watershed (Figure 3, page 10).
One pit was situated against Principio Creek at the head of
Furnace Bay. .
Excavation for sand and gravel has now exposed extensive
areas of the Furnace Bay watershed, and undoubtedly affects
both the character of sediments and their rate of deposition
into Furnace Bay.
19
-------
SECTION 4
SUBMERGED AQUATIC VEGETATION (SAV)
INTRODUCTION
Extensive beds of submerged aquatic macrophytes (SAV) have been a famil-
iar, and variously appreciated, aspect of most tributaries and shoal areas of
Chesapeake Bay. Though they can be a nuisance to recreational boaters, the
beds provide food and/or shelter to a wide variety of organisms, including
waterfowl, fish and a host of invertebrates. Additionally, SAV communities
remove some toxins from the water, stabilize sediments and dampen waves
responsible for shoreline erosion (Stevenson and Confer 1978).
Research on SAV ecology and distribution in the Bay has been sporadic.
Dramatic events such as the spread of water chestnut (Trapa natans) throughout
the Potomac in the 1920's, or the decline of eelgrass (Zostera marina) in the
southern Bay during the 1930's, have drawn attention to SAV communities.
Waterfowl biologists have provided descriptions of and investigations into the
grasses since the turn of the century.
Not until 1958, however, with the initiation of a SAV survey in the
Susquehanna Flats (Bayley et al. 1978), has there been systematic monitoring
of grass beds. Since then various investigators (Anderson 1972, Southwick
and Pine 1975, Steenis et al. 1962, Stevenson and Confer 1978) have docu-
mented the explosive spread and sudden decline of Eurasian milfoil
(Myriophyllum spicatum) throughout the Maryland tributaries during the late
1950's and early 1960's, and the startling disappearance of grass beds
throughout the northern Bay in the wake of Hurricane Agnes in 1972. The
post-Agnes decline of SAV beds in the Upper Bay coincided with the rapid
deterioration of eelgrass beds in the Lower Bay (Orth 1976).
At present, the most extensive SAV communities occupy the tidal rivers
of the central Eastern Shore. Vegetation is gradually returning to a few
Western Shore rivers, notably the Severn, Gunpowder, and the Bush Rivers, but
so far it is not recolonizing extensively the Susquehanna Flats, the Elk,
Bohemian or Sassafras Rivers. SAV is conspicuously absent from the Patuxent
River and most of the Potomac River. In Virginia, eelgrass beds remain
greatly reduced compared to 1971, but there have been no significant declines
in the past 2 years.
The recent record suggests that SAV communities are unpredictable and
prone to large swings in abundance and in species composition. \
Our 1-year feasibility study grew out of a desire to know more about the
broad history of SAV populations in different tributaries of Chesapeake Bay.
20
-------
It was felt that such information would complement ongoing ecological studies
in providing perspective on the behavior of grass beds over the course of
decades and centuries, rather than months or years.
naques^avedaeerteexprlroeed:^
thed M^^cfxmwm^^s^^e^^^^e^re^eo^oma^Ba^^GQsy&^eB^ Hew=has— SAfo
In order to address these questions, an attempt was made this year to
determine (1) the parts of SAV that are best preserved in the sediment and
that are most readily identifiable and whether or not there is selective
preservation,' and (2) the amount of variability in the spatial distribution
of the seeds in the sediments.
The biostratigraphic record of SAV in Bay sediments includes pollen,
leaf and rhizome tissue and seeds. Depending upon their state of preserva-
tion, the leaves of Elodea canadensis , Vallisneria americana, Myriaphyllum
spicatum , Zostera marina , Potamogeton. perfol-iatus , P. crispus and
Ceratophyllum demersum may be identifiable. Leaves of the genus Najas are
also recognizable. Unfortunately, leaves are often, fragmented beyond recog-
nition, and they are difficult to quantify. Nonetheless, leaves present a
record of presence or absence which may provide the best available informa-
tion for some species.
Seed and pollen production of major SAV species is summarized in
Table 3. Note that only, five species produce pollen with a persistent exine.
Members of the genus Potamogeton and Myriophyllum spioatum produce aerial
flowers and the pollen is wind-dispersed. Pollen of Elodea canadens-is and
ValHsneria americana is released at the water surface and distributed
locally. None of the SAV species produce enough pollen to figure signifi-
cantly in the pollen assemblage, although pollen grains of Myrioptyllum and
Potamogeton appear consistently in some of the cores analyzed.
^t^-most^^
toeomma rcfctJes , and they tend to be well preserved in most sedi-
ments. Fragments are recognizable to genus and usually to species. However,
seed profiles in the sediment are not easily interpreted. As underlined by
Watts (1967), tfp^liesiaeeidifjfe^ the fossil record so
that the prolific seed producers and those whose seeds are well preserved are
overrepresented compared to those species which produce few seeds or do not
preserve well. There is variation in the distance over which different seeds
are transported and in the palatability of different species to waterfowl,
fish and invertebrates. Finally, the ecology of a macrofossil community must
be known in order to draw meaningful inferences from the fossil record. ;
21
-------
TABLE 3. SAV SEEDS AND POLLEN IN THE BIOSTRATIGRAPHIC RECORD
•
Pollen with
Salinity persistent
range:(ppt) Pollination exine
Zostera marina
Potamogeton pectinatus
Potamogeton perfoliatus
Ruppia maritima
Zannichellia palustris
Najas qualalupensis
Najas flexilis
Etodea oanadensis
Vallisneria americana
Myriophyllum spicatum
10
0
2
5
0
0
0
0
0
0
- 35
- 8
- 25
- 35
- 8
- 10
- 10
- 10
- 1
- 20
hydrophily
anemophily +
anemophily +
ephydrophily
hydrophily
hydrophily
hydrophily -
ephydrophily +
ephydrophily +
anemophily +
Representation
in seed record
?
poor
poor
good
good
good
good
poor
good
poor
An example of SAV fossil assemblage is shown in Figure 6. The core is
from Furnace Bay. Five species occur in the profile. The assemblage suggests
that:
1. None of the species provide consistent records of seeds, pollen and
leaf tissue.
2. Myriophyllum spicatum and Vallisneria americana show good agreement
between seed and tissue presence, while Najas spp., Potamogeton spp. (in
this case predominantly P. gramineus) and Elodea oanadensis show a poor cor-
relation.
3. Of the four genera, Potamogeton is most poorly represented in the
seed record. This is probably due to poor preservation or the exceptional
palatibility of Potamogeton seeds to waterfowl and not to low seed production
(Stark 1971). Leaf fragments are the best markers of former beds of this
genus.
4. Pollen is not a useful parameter in the SAV record, since the species
represented are anemophilous, making it difficult to identify the location of
former beds. Also, the pollen records show poor agreement with seed and leaf
records.
22
-------
SEEDS/cm3 OF SEDIMENT
PRESENCE OF IDENTIFIABLE LEAVES
POLLEN PRESENT
I I
0 0.2 0.4
00.1 00.1 OO.I
A- VALLISNERIA AMERICANA
B- NAJAS SPP. .
C- POTAMOGETON SPP.
D- MYRIOPHYLLUM SPICATUM .
E- ELODEA CANADENSIS
Figure 6. An example of the SAV fossil record (Core FB-II from Furnace Bay)
23
-------
5. For most species, seeds afford the best fossil parameter for study-
ing the past history of SAV.
DISTRIBUTIONS OF SEEDS IN SEDIMENTS
In order to interpret the occurrence of seeds in the sedimentary record,
the decision was made to investigate the distribution of seeds in surface
sediments and to try to relate the seed populations to populations of SAV in
existing beds.
SAV reproduce asexual ly by rhizomes, turions, tubers and in many genera
(e.g., Myriophyllwn and Elodea) by any fragment of the plant axis bearing a
dormant lateral bud (Sculthorpe 1967). Typically, senescent plants fragmen- •
tize at the end of the growing season and drift in rafts that may accumulate
against the shore. Seeds may travel and settle with such rafts, or they can
become detached to be moved by waterfowl, wind and water currents (Stevenson
and Confer 1978, Sculthorpe 1967). The unique productivity, palatability and
dispersal mechanisms of the seeds of each SAV species suggest that it may be
difficult to make many generalizations about the transport of seeds. However,
empirical evidence from this study, described below, as well as that of Stark
(1971), Birks (1972), Praeger (1913), and Ridley (1930) suggest that seeds of
many SAV species do not travel far from the parent bed.
Area of Study
is a tidal tributary of the Miles River (Figure 7). It is
approximately 5 km long and its width decreases from about 500 m near the
mouth to 125 m near the head. A channel running up the center of the creek
rises from a depth of 4.5 m near the mouth to 2.4 m just south of the Tunis
Mills Bridge.
The SAV of Leeds Creek has been surveyed during the summers of 1976, 1977
and 1978 by the Youth Conservation Corps in collaboration with the Chesapeake
Bay Foundation (Fenwick, unpublished manuscript). Additionally, an aerial
survey outlined the location of SAV beds during the 1978 growing season
(Figure 7) (Anderson et al., in press).
Since 1976, the distribution and composition of SAV communities in Leeds
Creek have remained relatively stable compared to other SAV communities in the
•area.* . ' ;
Leeds Creek was chosen for a study of the dispersal and deposition of the
seeds of a few SAV species because of the work described above. In March
1979, surface sediments were collected from 77 locations along nine transects
inside the creek and from three locations just outside the creek (Figure 7). ':
The spatial distribution of seeds was compared to the distribution of SAV beds
in the previous growing season to see how far seeds of different species were
transported and whether they were concentrated at certain water depths. The
*Fenwick, G. 1979. Personal communication.
24
-------
Figure 7. Locations of surface sediment transects in Leeds Creek. Black areas
represent locations of SAV beds in 1978 outlined by aerial photogra-
phy (Anderson, in press). Bracketed numbered areas denote areas
sampled for SAV in 1978.
-------
1978 ground cover estimates for each SAV species were checked also against
seed data to see how the different species were represented in the sedimentary
seed record.
The results of the study are used in interpreting SAV biostratigraphic
profiles and in designing future studies.
Methods
The surface samples were collected with a piston corer 5.4 cm in diameter
that was designed for this project. A short core was drawn from which all but
the upper 28 cm3 (± 3 cm3) were discarded. Samples Were stored in plastic
bags and refrigerated as soon as possible.
The methodology for seed extraction and enumeration has been described in
detail in the EPA Quality Assurance Report for this project.
Samples were located by transect and water depth (Figure 7). At loca-
tions A, B and C paired samples on a line from the creek channel into the
Miles River were taken. Along transects 0 through G, samples were collected
under 0.6, 1.2, 1.8 and 2.4 m of water as well as in the deepest part of the
channel (approximately the center of the creek). These four transects were
separated by 122 m in an area that had extensive SAV beds the previous summer.
Along transects H through L samples were collected from 0.6, 1.2, and 1.8 m
water depths as well as in the center of the creek.
Results
Seed data for Zanni^ohell-La palustris, Ruppia maritima and Potamogeton
peotinatus are illustrated in Figures 8, 9, and 10. Table 4 lists the sample
data in seeds/cm3 of sediment for each species.
Homogeneity of Seed Distributions-
Data for Zannichellia palustris and Ruppia maritima are used separately
to test two hypotheses: (1) seed concentrations do not .vary between water
depths, and (2) seed concentrations do not vary between transects.
Potamogeton peotinatus is not included in the analysis because 68 percent of
the samples do not contain Potamogeton seeds.
Seed concentrations are strikingly low in the channel sediments.
Taroiiahellia seeds occur in 58 out of 60 (97 percent) of the nonchannel
samples and in 8 out of 20 (40 percent) of the channel samples. Ruppia seeds
are present in 58 out of 60 (88 percent) of the nonchannel samples and 3 out
of 20 (15 percent) of the channel samples.
The Kruskal-Wallis nonparametric test (Hollander and Wolfe 1973) was used
to determine whether the seed concentrations of the seven populations from the
sediments at 0.6 m, 1.2 m, and 1.8 m water depths on both sides of the creek
and from channel sediments vary with depth of water.
The Kruskal-Wallis test is similar to a rank-sum test for more than two
populations. It tests the probability, in this case, that the seed data are
26
-------
SOURCE
ii i
OF TEXT
05 12 1.8 24
DEPTH IN METERS
c
B
A
4.2
4.2
eo
2.4
00
1B
24 18 12 Q6
MOUTH
Figure 8. Seed concentrations of Zan-lohellia palustris in surface sediments
of Leeds Creek.
27
BOTTOM OF
IMAGE AREA:
OUTSIDE
DIMENSION
FOR TABLES
AND ILLUS-
TRATIONS
-------
BEGin
LAST LiN;
OF TEXT':
Q6 1.2 1.8 2.4
DEPTH IN METERS
c
B
A-
4.2
0-
4.2
00
2.4 1.8 12 Q6
MOUTH
24
oo
1.8
Figure 9. Seed concentrations of Ruppia maritima in surface sediments of
Leeds Creek.
' .••"'-'•'•' 28
IMAGE AREA;
FOR TABLES
AND !LLU£-
T RATIONS
-------
Q6 1.2 1B 2.4
DEPTH IN METERS
c
B
A
42
oo
4.2
oo
2.4 1.8 1.2 0.6
MOUTH
24
00
1.8
LAST UMF.J.Figure 10. Seed concentrations of Potamogeton pectinatus in surface sedi-
^ T~VT ments of Leeds Creek.
29
PAGf- .'-iljM^EH
BOTTOM Or
'MAGE APE'
-------
TABLE 4. SAV SEED CONCENTRATIONS IFlEEDS CREEK SURFACE SEDIMENTS
CO
o
Seeds/cm3
. West side
Species Transect
Zannichellia palustris A
B
C
D
E
F
G
H
I
0
K
L
Ruppia maritvna A
B
C
D
E
F
6
H
I
J
K
L
Potconogeton pectinatus A
B
C
D
E
F
G
H
I
J
K
L
Cl
0.00
0.00
0.03
0.06
0.03
0.03
0.08
0.03
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.03
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
C2
0.00
0.00
0.03
0.06
0.00
0.00
0.00
0.00
0.03
0.00
0.00
0.00
0.00
0.03
0.00
0.00
0.00
0,00
0:00
0.00
0.00
0.00
0.00 .
0.6 m
0.04
0.13
0.36
0.17
0.00
0.28
0.23
0.60
0.17
0.00
0.03
0.07
0.17
0.00
0.20
0.00
0.07
0.00
0.00
Q.,03
0.00
0.07
0.00
0.04
0.00
0.00
0.00
T.2 m;
0.47*
0.32
0.86
0.45
0.31
0.20
0.46
0.66
0.30
0.00*
0.00
0.10
0.19
0.34
0.08
0.09
0.07
0.19
0.05*
0.03
0.10
0.00
0.00
0.00
0..05
0.00
0.04
at water
of creek
1.8 m
0.34*
0.33
0.76
0.47
0.41
0.12
0.20
0.11
0.24*
0.06
0.10
0.33
0.14
0.24
0.20
0.04
0.02*
0.00
0.00
0.03
0.04
0.00
0.04
0.00
2.4 m
0.06
0.27
0.28
0.54
0.07
0.03
0.06
0.25
0.03
0.00
0.03
0.00
2
1
0
0
0
0
0
0
0
0
0
0
0
depths sampl
East side
.4 m
.0
.13
.62
.23
.30
.27
.42
.23
.00
.07
.00
.00
1.8 m
1.12
0.37
0.16
0.83
0.07
0.12
0.13
0.04
0.39
0.10
0.10
0.47
0.04
0.12
0.03
0.04
0.07
0.03
0.00
0.00
0.00
0.00
0.00
0.04
ed
of creek
1.2 m
0.26
0.37
0.13
0.22
0.29
0.18
0.32
0.64
0.35
0.19
0.17
0.10
0.32
0.13
0.04
0.18
0.03
0.18
0.07
0.17
0.10
0.03
0.00
0.00
0.00
0.030
0.04
0.6 m
0.07
0.11
0.11
0.00
0.04
0.27
0.04
1.70
0.17
0.04
0.07
0.04
0.00
0.04
0.08
0.04
0.12
0.08
0.04
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Actual depths greater than 1.2 m and 1.8 m due to steep-sided sand bar.
-------
derived from the same population using a statistic that is chi-square distrib-
uted.
Based upon this test, the hypothesis is rejected that seed concentrations
at 0.6 m, 1.2 m, 1.8 m and channel depths and at 0.6 m, 1.2 m and 1.8 m depths
are derived from the same population. The hypothesis is accepted that seed
concentrations at 1.2 m and 1.8 m are derived from the same population
(Table 5).
Results of the test are the same for seed concentrations of both Ruppia
and Zannichellia.
In order to test the second hypothesis that seed concentrations at all
transects are derived from the same population, transects D through K includ-
ing data from 0.6m, 1.2m, 1.8m and channel depths were compared again using
the Kruskal-Wallis test. The hypothesis is accepted for both Zarm-iohellia and
Ruppia, although not as strongly for Ruppia (Table 5).
The test results for the first hypothesis indicate that seeds are depos-
ited more consistently in sediments between 1 and 2 m of water than at 0.6 m,
where there is a lot of variability in concentrations, or in the channel where
they are virtually absent. Their absence in the channel suggests that the
seeds are not transported far in a lateral direction from their source because
the channel is the farthest location from the parent beds.
The results of the test for the second hypothesis, that seeds from all
transects are from the same population, suggest that either the plants are
uniformly distributed along the creek, thus producing uniform seed distribu-
tions, or that the seed distributions were homogenized longitudinally by
transport process. The distribution of plants for 1977-1978 is not suf-
ficiently detailed to indicate how uniformly the beds were distributed.
Aerial photographs and field data from 1978 indicate that the parent beds may
have been patchily distributed with denser beds below transect J, suggesting
that longitudinal transport mechanisms are responsible for the similarity of
seed populations between transects. The presence of seeds at transect L,
where no vegetation was mapped in 1978, supports this expectation.
The data from transects D through 6 were used to calculate the number of
samples needed to estimate (± 10 percent) the mean seed concentration in sur-
face sediments of that area at three different levels of confidence for each
species (Table 6). This is one way of examining the amount of variability in
seed concentrations among the samples from a small area of the creek. The
large sample sizes recommended by the test emphasize the degree of scatter in
the data. Sampling only at 1.2 m and 1.8 m depths, where the seeds are depos-
ited more consistently, reduces the necessary sample size, but still many
samples are required.
If the spatial variability in seed flux is the same roughly from year-to-
year, then there is little chance of obtaining quantitative trends in SAV pop-
ulations by observing seed concentrations in only a few cores. Spatial vari-
ability in seed flux could obliterate any temporal trends in SAV populations.
On the other hand, the samples are sufficiently similar in the presence and
31
-------
TABlE'"!5\~WALY"SiS"OrrEEbS'"CREE'R"SA'V"'SEED' CONCENTRATIONS USING KRUSKAL-WALLIS NONPAR/METRIC TEST (HOLLANDER
AND WOLFE 1973) . : ;•;.:.;::. , ."•_.. . _j
Hypothesis
Species
Sample
Result
il. [Seed concentrations do not
1 vary between depths.
Zanniohetlia palustris
Transects D-K
0.6 m, 1.2 m, 1.8 m,
and channel
I
Transects D-K
0.6 m, 1.2m, 1.8 m
Transects D-K
1.2 m, 1.8 m
Ruppia maritima
c^.L.
ro.-:
Transects D-K
0.6 m, 1.2m, 1.8 m,
and channel
Transects D-K
0.6 m, 1.2 m, 1.8 m
Transects D-K
1.2 m, 1.8 m
reject (p < 0.01)
reject '(p < 0.01)
accept (p = 0.30)
reject (p < 0.01)
i
reject (p < 0.01)
i
accept (p = 0.20)
2.
Seed concentrations do not
vary between transects.
Zannichellia palustris
Ruppia maritima
Transects D-K
0.6 m, 1.2 m, 1.8 m,
and channel
Transects D-K
0.6 m, 1.2 m, 1.8 m,
and channel
> 'ri O O — cb
~- p r: C" •> O
IIW&
* m & ;,, ,,
accept (p = 0.80)
accept (p = 0.70)
-------
absence of major SAV species, especially samples from 1.2 m and 1.8 m, that
presence-absence records of dominant SAV species in Leeds Creek could be
assembled from a much smaller number of samples.
TABLE 6. NUMBER OF SAMPLES REQUIRED TO BE 80, 90, and 95 PERCENT CONFIDENT OF
ESTIMATING (WITHIN 10 PERCENT.) MEAN SAV SEED CONCENTRATIONS IN TRANSECTS D-G
(SNEDECOR AND COCHRAN 1976)
Plant species
ZannichelZia
Zannidhellia
Zannichellia
Zannichellia
Zannichellia
Zannichetlia
Ruppia
Ruppia
Ruppia
Ruppia
Ruppia
Ruppia
Potamogeton
Potamogeton
Potamogeton
Potamogeton
Potamogeton
Potamogeton
Water depths Mean
included in mean seeds/cm3
0.6
0.6
0.6
1.2
1.2
1.2
0.6
0.6
0.6
1.2
1.2
1.2
0.6
0.6
0.6
1.2
1.2
1.2
- 1.8 m +
- 1.8 m +
- 1.8 m +
- 1.8 m
- 1.8 m
- 1.8 m
- 1.8 m +
- 1.8 m +
- 1.8 m +
- 1.8 m
-1.8m
- 1.8 m
- 1.8 m +
- 1.8 m +
- 1.8 m +
- 1.8 m
-1.8m
- 1.8 m
channel
channel
channel
channel
channel
channel
channel
channel
channel
0.309
0.309
0.309
0.466
0.466
0.466
0.139
0.139
0.139
0.215
0.215
0.215
0.037
0.037
0.037
0.056
0.056
0.056
Variance
0.079
0.079
0.079
0.074
0.074
0.074
0.025
0.025
0.025
0.029
0.029
0.029
0.005
0.005
0.005
0.007
0.007
0.007
Level of
confidence
(%)
95
90
80
95
90
80
95
90
80
95
90
80
95
90
80
95
90
80
No. of
sampl es
necessary
331
223
138
137
92
57
518
348
215
251
169
105
1461
983
608
893
600
372
33
-------
BEGIN
i f-A '; T ; ;
OF TEX-
Comparisons of Seed Distributions in Surface Sediments with the 1978
Vegetation Survey—
The results of 1978 field sampling at five locations (Figure 7) in Leeds
Creek are summarized in Table 7 (Fenwick and Maldeis, manuscript in prepara-
tion). Five SAV species are recorded in Leeds Creek in 1978. Three of the
five species are present in the seed record. These three species (Ruppia
maritima, Zannicheilia palustris and Potamogeton pectinatus) account for 98.9
percent of the ground cover (as visually estimated) in the areas sampled in
1978. Data in Table 7 suggest that Zannicheilia is overrepresented in the
seed record (compared to Ruppia) since Zannicheilia seeds occur in consis-
tently higher concentrations than Ruppia seeds, despite 87.3 percent ground
coverage by Ruppia and only 8.5 percent by Zannicheilia. The 1978 ground
cover data may underestimate the extent of Zannicheilia in the creek since
they were collected in July, and Zannicheilia populations often decline by
late June (Stevenson and Confer 1978). Additionally, Zannicheilia beds may
have a higher seed output than Ruppia beds, or the seeds may suffer less
predation by waterfowl and other organisms than Ruppia seeds. Both species
preserve well in the sediments.
TABLE 7. RESULTS OF THE 1978 LEEDS CREEK SAV SURVEY (FENWICK AND MALDEIS,
MANUSCRIPT IN PREPARATION).
.Stations
with
Ground Cover
\ Stations Vegetation Ruppia Zanniahellia Potamogeton Elodea Potamogeton
Area (n) (%) maritima palustris pectinatus canadensis perfoliatus
38
48
57
28
32
Average:
.58
83
;79
i
79
50
i
69.8
83.9
72.4
95.6
85.3
99.1
87.3
11.8
12.0
3.3
14.7
0.9
8.5
15.6
4.1
1.1
0.2
3.1
1.0
< 0.1
Potamogeton 'perfoliatus and Elodea canadensis are minor components of
the 1978 plant community. They do not appear in the seed record of the sur-
face sediments. • I
' i
i
I Because Ruppia and Zannicheilia beds were scattered through the creek,
jit was difficult to estimate the distances over which their seeds might have
been transported by water currents. Seeds did occur in appreciable numbers
:250 m upstream from the nearest reported beds. Potamogeton pectinatus seeds
occurred as far as 3.5 km from the beds at the mouth of the creek, though the
BOTTOiv"
IMAGE P
-_•' O ! *J i L-' v.
viMEMS!
CUR TAB
TRATiOriS
-------
majority of seeds occurred along the four transects (D-G) in proximity to
where the species was growing in 1978. Waterfowl may have played a role in
the broad dispersal of Potamogeton seeds.
LAST L.ii-
OF T2XT
of SAV seeds are h^^^f^mb^^n^^M^e-se^mes^ but
^are^
eep. The distributions are not unexpected in view of
the fact that distributions of SAV species are extremely patchy and the size
of the seeds (disregarding floating mechanisms) determines that they are not
likely to be transported any great distance by estuarine processes. The a/Adfe-
abttrtj that is characteristic of these distributions ^§§es;t-Sjdfeteat data from
a large^uWer^ofecoEes^^
anyasiis:ni:fe However, majiOKstiEenjcteEiaJBdons-
SAV BIOSTRATIGRAPHY OF UPPER CHESAPEAKE BAY
i
The Susquehanna Flats was chosen as a site for a study of SAV biostratig-
raphy because the area has had a diverse and extensive SAV community, in the
past. Also, since 1958, the vegetation has been sampled along 37 km of tran-
sects by scientists from the Migratory Bird Habitat and Research Laboratory •
,(MBHRL). The results of this survey are summarized by Bayley et al. (1978).
from the SusquehannaEftats and foinfecoieesu from t
were analyzed for SAV seeds. Our.objectives were: (1) to see how variable
the seed record is between cores within each area, (2) to compare the SAV ;
records of two areas closely related spatially but different hydrodynamically,
(3) to test the SAV record of recent sediments against the distribution of SAV
beds during those years as established by the MBHRL Survey, and (4) generally,
to gain some measure of the resolving power of the biostratigraphic approach
as applied to SAV populations while examining trends in SAV populations of the
Upper Chesapeake Bay before and after European settlement.
i :
The Susquehanna Flats j
Core locations in the Susquehanna Flats are in the v.icintiy of the MBHRL
sampling transect which ran between Havre de Grace and Spesutie Island (see
Figure 2). It was hoped that the locations would be far enough south of the
Susquehanna River so sediments would be free from periodic scouring, as im-
plied by the U. S. Army Corps of Engineers (1975). Using a piston corer
5.42 cm in diameter two cores from site 1, two from site 2, and one from
site 3 were collected (Figure 2). One core from each site has been analyzed
.(Figure 11). : j
_i The methodology for seed extraction and enumeration is provided in the
:EPA Quality Assurance Report. Results are plotted as seeds per.cm3 of sedi-
ment in Figures 12 through 16.
BOT
IMA
OUT
TOM Cr
GE AREA:
SIDE
Q 3/8"
TABLES.
D iLLUS-
-------
FB-I F8-2 FB-3 FB-4
E
u
Q.
UJ
Q
H-
z
Id
Q
LJ
Cfl
20
40
60
80
100
120
140
XXX
7-7-7
xx/
Y7/
7/
x/
VZ
x
XXX
zz:
'XX
SF-I SF-2 SF-3
777
.XX,
zz
//
//x
//x
Y7,
SAMPLE ANALYZED FOR SAV SEEDS
Figure 11. Upper Chesapeake Bay cores showing levels analyzed for SAV seeds,
36
-------
SF, I
SF2
SF 3
CO
u
to
20
I30
H40
a.
UJ
°50
60
70
80
*
#
*
*
*
*
b
3
*
*
*
*
*
1 — I I — J —
0 O.I 0.2 0.3
SEEDS/cm3 SEDIMENT
0
10
20
_ 30
E
U
i40
fL
iu 50
o
6O
70
80
90
*
j
*
F'
*
*
*
*
3
*
1 , ,
0 O.I 0.2
u
10
20
30
40
50
—
§ 60
x
t- 70
Q.
UJ
O
80
90
SEEDS/cm3 SED. 100
110
120
• NO SEEDS
130
i /in
*
•
*
*
]
*
*
*
*
|
*
]
*
*
]
* i i.
0 O.I 0.2
SEEDS/cm3 SED.
Figure 12. Seed concentrations of Vallisneria americana in cores from Susquehanna Flats.
-------
U)
00
0
10
20
I 3°
x
Q.
UJ
O
40
50
70
80
*
tJ
SF I
0 O.I 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
SEEDS/cm3 SEDIMENT
SF 2
u
10
20
-30
u
h-
0.
UJ50
o
6O
70
80
90
*
*
*
1
I
ID "? '
H
*
*
* 1 1 1 J 1
0 O.I 0.2 0.3 0.4 0.5
SEEDS/cm3 SEDIMENT
• NO SEEDS
SF 3
V
10
20
30
40
50
I60
fro
Q.
UJ
°80
90
100
no
120
130
tan
h
^i
*
—LI
T~^
*
D
i
*
H
ID
l , ,
SEEDS/cm3 SED
Figure 13. Seed concentrations of Sajaa flexilis in cores from Susquehanna Flats
,, ,. ,, ;, ,,, £ -
-------
oo
vo
SF I
SF 2
u
10
20
E 30
I
I- 40
Q.
LL!
°50
60
70
80
*
*
*
*
*
*
*
*
*
*
*
D
*
1 i i
0 O.I 0.2
SEEDS/cm3 SED.
u
10
20
,. 30
E
u
i40
o.
uj 50
o
60
70
80
90
*
*
I)
*
*
*
*
*
* i i
0 O.I 0.2
SEEDS/cm3 SEO.
« NO SEEDS
Q.
UJ
O
0
10
20
30
40
50
60
70
80
90
100
'110
120
130
140
SF 3
0 O.I 0,2
SEEDS/cm3 SED.
Figure 14. Seed concentrations of Elodea oanadensis in cores from Susquehanna Flats.
-------
SFI
SF 2
SF3
.£»
O
0
10
20 3
5 30
0.
UJ
o
40
50
60
70
*
k
80H
0 O.I 0.2
SEEDS/cm3 SED.
u
10
20
"E
u
~ 40
X
& 50
o
6O
70
80
90
*
*
*
]
*
*
*
*
* i 1
0 O.I O.2
SEEDS/cm3 SED.
« NO SEEDS
u
10
20
30
40
5O
E 60
* 70
o.
IU
o
80
90
100
110
120
I3O
140
r
*
1*
L
b
*
*
Oe •
p
1
n
1
]
0 O.I 0.2
SEEDS/cm3 SED.
Figure 15. Seed concentrations of Potcmogeton spp..in cores from Susquehanna Flats.
-------
SFI
SF2
SF 3
0
10
20
I30
£ 40
Q.
UJ
°50
60
70
80
*
*
id
*
*
3
=3
i
*
*
*
*
' *
it
" * 1 1
Up
10
20
_ 30
E
u
~* 40
X
V-
Q.
ui SO
o
60
TO
80
0 O.I O.2
SEEDS/cm3 SED. 90
*
*
*
n,
?
]
*
*
'
*
*
* 1 1
0 O.I O.2
SEEDS/cm3 SED.
» NO SEEDS
u
10
20
30
40
50
1 60
570
Q.
UJ
O
80
90
100
110
120
130
I4D
*
b
*
*
*
*
»
*
*
*
*
*
i'
*
*
*
*
* i i
SEEDS/cm3 SED.
Figure 16. Seed concentrations of Myriophyllwn spioatwn in cores from Susquehanna Flats,
-------
~ ...... The cores contained seeds from. 10 species out of 18 SAV species reported
for this area (Bayley et al. 1978). Najas quadalipensis, Heteranthera dub-la,
Ceratophyllwn dem&csvm, Potamogeton peot-inatus and P. pusitlus each occurs
only once, Najas flexilisj P. gramineus^ Vall-isneria amer-icana, Elodea
oanadensis and Myriophyllwn spicatum appear more regularly.
.'" The greatest seed concentrations in Cores 1 and 2 coincide with a thick
band of coal particles. The Core 1 band lies between 32 and 42 cm; the Core 2
band is between 24 and 32 cm. In both cores, this coal zone occurs directly
above a band of. coarse sand and below a layer of silt and terrestrial detri-
tus. This pattern has been interpreted as the product of a major storm event,
most likely the 1972 Hurricane Agnes. SAV seeds that were resuspended with
upstream sediments apparently settled with the coal particles, producing a
distinct peak in the seed profiles. The peak is especially prominent in the
profiles f or Najas flexilis (Figure 12).
; In Core 3, the largest concentration of coal particles occurs between 3
and 7 cm though coal particles are apparent in all sediments above 98 cm. [
There is no abrupt climb in seed concentrations comparable to those in SF-1
and SF-2. Najas flexiHs and ValHsneria americana appear consistently
throughout the core. Seeds of Potamogeton spp. and Elodea canadens-is occur '.
sporadically, and Myriophyllum is limited to the top 12 cm.
I The major shifts in local SAV populations which have been documented in
field surveys since 1958 are not consistently depicted in the SAV record of
the Susquehanna Flats. The dominant species are the same in both (Najas sp.3
Myriophyllim sp-ioatum, Vallisneria amerl'cana, and Elodea canadensis ) , but
there is nothing in the cores comparable to the simultaneous rise of j
Myriophyllvm and decline of native grasses described in the MBHRL Survey dur-
ing the early 1960's. The disappearance of SAV after Hurricane Agnes, on the
bther hand, is indicated by the absence of SAV seeds in surface sediments of
all three cores. \ ;
'; • •
! It has been concluded that 6priynwf!@aBaFrH?s^^
because:-
; 1 . Sfedime«t-at40jtepat-ter5ws appear to
As seeds would not be deposited uniformly under such conditions, an unreal is-
tically large number of cores might be needed to reconstruct the long-term
behavior of SAV. ;
j : |
I 2. At a site, S'edaffleraifeai-a«n«:RaTbes=»also ^:»G%aat-e!S5tlramait2i5eaWf» making it
difficult to distinguish changes in seed concentrations due to changing sedi-
mentation rates from changes which reflect trends in SAV populations. The j
possibility of periodic scouring of sediments at a location makes interpreta- '
tions of seed assemblages still more difficult. I
| 3. Po^4e«^ewpsM*»«sac4rf«w^con€eRt^at^n5 that palynologically derived
sedimentation rates are difficult to obtain, and hence it may not be possible
BEGIN to compute a SAV flux in this area.
j FOR TABLES
•ID iLLUS-
-------
'".... Similarity of diatom stratigraphy of the Susquehanna Flats and Furnace
Bay implies that water quality is comparable in the two areas (Section 6).
Furnace Bay is a good depositional area making it appropriate for biostratig-
raphic studies. Thus there may be indirect information on trends in SAV of
the Flats which are related to changing water quality that can be inferred
from Furnace Bay data. This is true only if SAV, which contribute to the
Furnace Bay seed record, is responding to changes in water quality in a_way
that is representative of SAV in the area as a whole. " "~ .......
Furnace Bay is a broad, shallow embayment north of the Susquehanna Flats
and east of the Susquehanna River (see Figure 3). Sediment enters Furnace
Bay via Principio Creek, Mill Creek, Chesapeake Bay, and small streams which
drain the immediate watershed. The sediments in all six cores taken from
Furnace Bay are fine-grained (99 percent silt and clay) and relatively rich
in organic matter. Unlike the sediments from the Susquehanna Flats, there is
very little variation in sediment character with depth, which suggests that
the cores are taken from undisturbed depositional areas.
Four of the six cores were analyzed. FB-I and FB-II were taken at
sites 1 and 2; FB-III and FB-IV were taken less than 3 m apart at site 3
(Figure 3). All cores were collected with a 5.4 cm diameter piston corer.
FB-III and FB-IV were X-rayed by the Maryland Geological Survey; core •
sections X-rayed in FB-III showed banding patterns suggestive of undisturbed
stratigraphy. Comparable sections in FB-IV had no distinguishable zonation.
When all of the cores were split for subsampling, the gross structures of
FB-I, FB-II and FB-III were generally similar but differed from FB-IV.
! FB-I and FB-IV were divided into slices 2 cm thick and two slices were
analyzed within every 10 cm along the core. Because seed concentrations were
low, FB-II and FB-III were divided into 4 cm slices. In this pair of cores
every sample was analyzed (Figure 11).
;
I The methodology for seed extraction and enumeration is described in our
Quality Assurance Report. FB-I and FB-II were analyzed for pollen and dia-
toms as well as seeds (Sections 5 and 6). FB-III was partially analyzed for
pollen. , ' i
r i <
j The seed data are presented as seed flux per 10 cm2 per year in
Figures 17 through 22. The seed flux is obtained by multiplying seed con-
:centrations by sedimentation rates which were established through pollen
ianalysis. , j
i ' I
! Seed data for FB-IV have been included and are adjusted to a sedimenta-
tion rate of 0.6 cm per year, even though sedimentation rates were not actu-
!ally obtained for this core. Because FB-IV unquestionably has been mixed
vertically, it is not included in the following discussion of Furnace Bay
JSAV stratigraphy. j
TEXT ,i-;»
BOTTO
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:'•:' 'x
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60
70
80
90
I
FBI
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3- 1
... .. . -i
— — ,
Z3
g f
> 1.0 2.0
SEEDS/ 10 cm* /YEAR
DATE
.978 0
to
.930
20
.923 J0
40
900 so
,873 I60
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Figure 17. Seed flux of ValHsneria conericana in cores from Furnace Bay.
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Figure 18. Seed flux of Najas spp. in cores1 from Furnace Bay.
-------
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Figure 19. Seed flux of Elodea canadensis in cores from Furnace Bay.
-------
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Figure 20. Seed flux of Potamogeton spp. in cores from Furnace Bay.
-------
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Figure 21. Seed flux of Myriophyllwn sp-iaatwn in cores from Furnace Bay.
-------
ValHsneria americana —
Seeds of ValHsneria americana occur regularly in relatively high con-
centrations in FB-I, FB-II and FB-III. There are few sediment depths at
which ValHsneria seeds are low in all three cores.
s:co^
nteriva^
1;93:6 and^:889i. Total pollen flux in FB-I and FB-II does not change apprec- •
iably at these depths, so the drop in ValHsneria seed concentrations is
probably not a function of sedimentation rate.
In 41 of 80 Furnace Bay samples, ValHsneria seeds occur in concentra-
tions comparable to a flux rate of 0.5 seeds/10 cm2/year or more. If these
figures are representative, then over 500 seeds per m2 per year have been
deposited more or less regularly at the Furnace Bay coring sites during the
past 300 years. In view of the relatively low seed production and localized
dispersal patterns of SAV, it is believed that such a seed record could only
derive from dense beds of ValHsneria growing inside Furnace Bay.
In general it appears that toZ^isnei^^as^grown-corvtinuotts^ (or nearly
so) ^^^•.the^yf€i^~3'W^^^e^:s^^^^Gen!tury. This implies that the species
has persisted across periods of increased sedimentation (e.g., the late 19th
century) and increased nutrient levels (following the onset of sewage dis-^
charge into Mill Creek). Steenis (1970) has found ValHsneria to be tolerant
of "muddy roiled water" (Stevenson and Confer 1978).
Najas spp . —
The data for Najas flexilis and N. quadalupensis are grouped together in
Figure 18 even though seeds of the species are easily distinguished. The pro-
files of the two species in FB-I, FB-II and FB-III are very similar, and their
seeds occur in roughly equal numbers. Another reason for lumping the data is
that field surveys usually group the two species since they are difficult to
tell apart unless fruits are present.
are pnesenfei^ifcttje^orldest-^ediTnent* of all three cores. They
disappear simultaneously in the cores a«)trnd=3;S4:03<75-80 cm). They do not
appear in concentrations comparable to pre-1840 until 1910 (above 42 cm). The
failure of Najas to recolonize former habitats after Hurricane Agnes is shown
by the afasene* of seeds from the
The -Najas seed profiles could be interpreted several ways depending upon
the dispersal characteristics of the seeds. At one extreme, the Furnace Bay
sediments could collect seeds from the Susquehanna Flats, Mill Creek and
Furnace Bay itself, in which case a decrease in seed concentrations at a par-
ticular sediment depth would most likely describe a general decline of the
species in the area. At the other extreme, the source of seeds could be vege-
tation in the immediate vicinity of the coring sites, in which case the seed '•
flux would change dramatically with shifts in the distributions of Najas beds
as well as with decreases in abundance in local beds. ____ .....
49
-------
" Several observations suggest that the
^Eefe-a^-prndustsso^ SAV beds, and that
species of Najas were less abundant between 1840 and 1910 in an area at least
•'.7.'.-.." as large as Furnace Bay. These observations are:
; : 1. The same trends in the Najas seed flux are apparent in all three
; Furnace Bay cores.
2. If the Najas record were extremely local, one would expect some
amount of reciprocity in the seed records of Najas and ValHsneria. In fact,
the seed records of Najas spp. and ValHsneria act independently or similarly,
probably as a function of changing sedimentation rates.
3. Najas flexilis reproduces primarily sexually. It therefore produces
many seeds that are capable of being dispersed over large distances (Birks
1972, Stark 1975). N. guadalupensis apparently behaves similarly (Stevenson
and Confer 1978). Thus in spite of high sedimentation rates in the
Susquehanna Flats, the cores from that area (SF-1 and SF-3) contain
N. flexilis seeds in relatively high concentrations. The moderate to low con-
centrations of Najas spp. seeds in Furnace Bay sediments lead us to suspect "
that Najas spp. if present, have not dominated the vegetation in the vicinity
of the coring sites. Consequently, the seeds could be coming from a more
distant part of Furnace Bay or perhaps floating in from the Susquehanna Flats.
4. The decrease in Najas seed flux continues for 70 years.
! In circumspect, the Najas profiles might represent the disappearance from
and eventual return to Furnace Bay of small local populations. They also
could represent a decline in the species over a larger area than Furnace Bay-
perhaps over an area extending into the northern Susquehanna Flats.
• The decline in the abundance of Najas spp. coincides with a period when
suspended sediments were probably at high levels in the Susquehanna River as a
result of extensive deforestation in the watershed. We know of no data that
suggest Najas spp. are especially intolerant of increases in turbidity. In
fact, Najas spp. can grow in lower light conditions than many other SAV
species (Martin and Uhler 1939). There may have been associated changes in
water or sediment quality of the area which adversely affected the Najas pop-
ulations. Species of Najas occur on a wide variety of substrates, although
they thrive in predominantly sandy sediments (Stevenson and Confer 1978).
• .' ' i
Elodea aanadens-is— \
\ With the exception of one seed, at 8-12 cm in FB-III, the recent sediments
of Furnace Bay do not contain any seeds of Elodea (Figure 19). Seeds occur
consistently in low numbers in FB-II until 1780 (95 cm), sporadically until
f!890 (55 cm), and then disappear altogether. In FB-III, the species disap-
pears from the record by 1760 (97 cm). No Elodea seeds are contained in FB-I.
i(Sediments from this core are younger than 1810.) S07~
| ! . i !
BtGir.; j Elodea was a prominent member of SAV communities of the Susquehanna Flats
LASj_LIN£ between 1958 and 1971 (Bayley et al. 1978). Judging by the seed profiles, the ...IMENSIO';
Or iLxr -plants which .grew in the .Flats .during that, .time .didjiot_<:ontrj bute.]much _to J FOP TABLES
-------
Furnace Bay seed assemblages. This is probably due in part to Elodea's low
seed output (the species reproduces primarily asexually). Thus the seed
--..-. .:: record from 18th century sediments probably describes relatively dense beds
of E-L0J&&, in or near Furnace Bay which deeMned^TOmd^he^4me^t^e^urs
;:".-;..; Pound:i:ngKareaswas--e4eaved»for--ag:feieu^tuti«. This is somewhat enigmatic since
Efodea^ene^a3%^oesirwe,l3lH^^ (Stevenson and
7 Confer 1978). _ _ _ •
Potamogeton spp. —
The Potamogeton species have been grouped because fragments of seeds are
not always identifiable to species. Most of the seeds which can be identified
belong to P. gramineus (Figure 20).
Seeds are probably not a good indicator of former Potamogeton beds, since
they suffer high rates of predation by waterfowl and may not preserve well in
the sediments. There are no sediment depths which show consistent trends in
all cores. However, the leaf record indicates that p. gramineus may have had
a long tenure in the area.
Myriophyllum"spioatum— ; "" •''";
Myriophyllum did not figure prominently in the SAV communities of the
Upper Bay until the late 1950's, despite its introduction into the United
States in 1895. Between 1957 and 1959, the percentage of sampling stations
at which Myriophyllum was recorded jumped from 0 to 47 percent (Bayley
et al. 1978).
; The first Myriophyllum seeds appear in FB-II at 30 cm and in FB-I and
FB-III at 26 cm and 24 cm (the Myriophyllum seed at 64 on in FB-IV is taken \
as further evidence that this core has been vertically mixed). If 1959 is
considered as the year Myriophyllum first appeared, then the seed record from
Furnace Bay implies a sedimentation rate of 1.3 cm/year which is twice as
high as the rate determined for Furnace Bay by pollen analysis. If we accept
the sedimentation rates provided by pollen analysis, then Myriophyllum would
have occurred in Furnace Bay as early as 1930.
CONCLUSIONS \ • \ . :
i SAV seed assemblages in sediments from Leeds Creek, the Susquehanna Flats
and Furnace Bay reflect former beds of dominant SAV. The assemblages are a
function of the species composition of former beds as well as the local hydro-
logical patterns influencing seed deposition. The data show that the SAV
record represents local populations and that there is large variability in the
annual SAV seed flux within a locale. ', ' •
\ In designing a sampling program to study past distributions of SAV,
there is a trade-off between the number of cores that can be studied from
an area and the resolution at which any single core can be analyzed. This
jis so because considerable time is involved in the analysis of any one core
BEGIN for SAV seeds. Since spatial variability may mask any minor temporal trends,
LAST_>--•:£-the recommendation is to take several cores from a locale and divide each —
Ur i t
core into a practically small number of ..samples ,so ..the major .trends jn.
BOTTOM OF
IMAGE AREA
FOR TABLES
-------
dominant SAV over time are defined. The number of samples needed to divide
the core into such time intervals will vary with the sedimentation rates
characteristic of the study area.
The results also suggest that an impractically large number of cores
would be required to study the history of SAV populations using a sampling
program designed on a regional scale. Instead, sites should -be chosen within
a tributary that are likely to reveal responses of local SAV populations to
regional changes in water quality due to increased sedimentation, eutrophica-
tion, etc. This means that cores should be taken from good depositional
areas strategically located within the tributary (e.g., upstream and down-
stream from point sources of nutrients, in areas now devoid of SAV which had
good SAV populations in the past, etc.). If the same dominant SAV popula-
tions show similar trends in a few local areas subjected to similar regional
impacts, some conclusions may be drawn about the effect of different kinds of
watershed disturbance (land use) and water quality on SAV.
52
-------
U-; " ."_ _ _________ ________ _____ SECTION 5 _________ ______________________________ ~ 7
SEDIMENT TRANSPORT AND DEPOSITION
INTRODUCTION ;
The fate of toxics and other substances transported into the tributaries
and main stem of the Bay are governed to a large extent by the transport of
sediment and its rate of deposition. Sedimentation rates indicate which areas
are filling in, how rapidly, and the influence of land use in different water-
sheds on the amount and rate of sediment deposited in the receiving water. ;
Sedimentation rates are necessary also for calculating the true deposition
rate" (flux) of seeds and diatoms. ..... ~ " ~ " --••••«,
: Sedimentation rates can be obtained by measuring the decay rates of
210Pb and ^C in the sediments. They also are calculated from exact dates
assigned to sedimentary horizons where there is a major change in the com-
position of the pollen assemblage originating from terrestrial plants. Pollen
grains of terrestrial plants are well preserved in sediments and reflect
major changes in the composition of the vegetation caused by climatic change,
disease and land use. Since the time of European settlement layers of sedi- ;
ment deposited that exhibit vegetational changes resulting from changing land
use often can be dated from historical records. Where the land use has been
manifold, several horizons may be dated in a core if it extends to presettle-
ment time or includes sediments deposited since early settlement. While the :
maximum resolution of 210Pb is approximately 1 to 100 years and llfC approxi-
mately 500 to 100,000 years, pollen does afford a means of dating sediments ;
too old or too young to be dated radiometrically. In this study, all sedi- ;
mentation rates were based upon pollen analyses. Cores are being analyzed ;
also that are dated by 210Pb from both the Potomac River and Chesapeake Bay \
in order to compare the two methods of dating. ;
l In this study, two of three questions were addressed, more or less j
fundamental to establishing a data base of sedimentation rates for the j
Chesapeake Bay system. It was sought to determine (1) the number of cores at
a location and throughout the length of an estuary necessary for obtaining \
data representative of the pollen deposited at a given time, and (2) the j
integrity of the vertical distributions of pollen as well as the number of j
horizons that can be dated using changes in sedimentary pollen assemblages. I
So far, the question of the effect of compaction of estuarine sediments on 1
Sedimentation rates has been left unanswered. This problem is being inves- j
tigated with the object of determining whether or not correction factors for ; IMAGE AREA
BEGIN (compaction of different sediment types are necessary for describing a true j OUTSIDE
LASTLINC- sedimentation rate. j — j DIMEHS.CN
OF TcX i '----" _ , ___ I _ _ j pQpj TABLES
-AND iLLUS-
TRATIONS
-------
In addition to providing information on the variability between samples,
the data obtained for determining the necessary number of cores also provided
information on the distance some sediment is transported within the estuary.
>2EGiN
LAS'" LiN
Or TEXT
SPATIAL DISTRIBUTIONS OF POLLEN IN ESTUARINE SEDIMENTS
Pollen distributions and hence the spatial variation of pollen in estua-
rine sediments are governed by (1) the distribution, pollen production, time
of flowering and pollination mechanisms of the source vegetation, (2) the
processes operating in the atmosphere and within the river including the
dynamics of transport, deposition, resuspension and redeposition, and (3) the
physical characteristics of the pollen controlling its susceptibility to the
transport phenomena.
An interpretation of pollen assemblages in surface sediments in terms of
| the interaction of these three factors will allow a better understanding of
:what a pollen assemblage at any one locality in the estuary represents in
;terms of vegetation type and land use. Thus, this would provide a basis on
which to interpret vertical changes in pollen assemblages with respect to •-•;
vegetation and land use in the past.
; In order to accomplish this objective, the spatial distribution of
pollen in surface sediments in the tidal stretch of the Potomac River is
described in order to .(1) identify the best depositional locations and the
number of samples necessary to obtain data representative of the vegetation,
•(2) determine the area of source vegetation represented by pollen in the sur-
; face sediment at any one location including the accuracy of the representa-
ition so that we might know the area for which historical records are needed
to date changes in the vertical pollen profile, and (3) determine the effect
of estuarine transport processes on the pollen distributions.
: In order to accomplish the first objective, comparisons were made of the
;total number of grains per gram dry sediment in the channel and nonchannel
•samples, the percent of total pollen of all the tree pollen types identified
iin channel and nonchannel samples; the degree of similarity with respect to
•=-percents of all pollen types between all channel samples was examined, and :
;the amount of variability that occurs between samples taken at the same Toca-
;tion was tested. Addressing the second objective, the degree of abun-dance of
the pollen types whose source vegetation occurs far upstream of the surface
:sediment samples was observed, percents of total pollen were compared with
I the respective percents of total basal area in the adjacent vegetation and
iefforts were made to detect any spatial trends in the pollen and/or vegeta-
|tion. Finally, with regard to the third objective, the degree of scatter
! observed in the pollen of the surface sediments was compared with the degree
iof scatter in the vegetation and the distribution of the poll-en in relation
!to their physical characteristics was investigated.
j The tidal Potomac River was chosen for this phase of the study because
!additional support was obtained from the U. S. Geological Survey for the
ELStudy, including collection of samples, which required 1 week of boat time, ._
;.-v*and analysis of samples. It was felt that results from the tidal Potomac
OfTTTO- • f,i-
i.JV_( f 1 v^..i •„';
OUTSIDE
DiMENSiO.1
54
'^ANO ILLU'J
: [RATIONS
-------
River with regard to the movement of small particles such as pollen and their
spatial distributions in the sediments would be applicable generally to all
tributaries, and it would at the very least provide guidelines for sampling
in the other tributaries.
Surface sediments were collected with a Shipley sediment sampler at 139
locations in 28 transects across the Potomac River from Alexandria, Virginia
to Point Lookout where the river enters the Chesapeake Bay. "This stretch "
includes almost all of the tidal Potomac. Triplicate samples were taken at
two transects. Of the samples collected, 48 from 13 transects and one set of
triplicates were analyzed (Figure 22).
Vegetation data used were collected in 1974 for compilation of a map of
the woody vegetation of Maryland (Brush et al., in press). The data consist
of basal area measurements of trees greater than 2 cm dbh* in 132 400 m2
plots located in 43 7-1/2 minute quadrangles (Figure 22). Plots are located
more or less randomly within the quadrangles; the number of plots in each
quadrangle is given later in Table 13 (page 66). The area chosen as a
source for the pollen is adjacent to the stretch of the river studied and
extends eastward to the Chesapeake Bay (Figure 22)."Forest associations are
separated by the presence or absence of loblolly pine, basket oak, willow
oak, blackjack oak, post oak, tulip poplar, river birch and sycamore. (See
Brush et al., in press, for the distributions and species composition of
forest associations throughout Maryland.) Although many of the forest asso-
ciations are separated on the basis of different species of the same genus
and most pollen are not identifiable to species, the potential exists for
identifying in the pollen assemblages those associations that are character-
ized by different genera. For example, sweet gum is closely associated with
loblolly pine. Both types drop out of the vegetation further north and west
where the forest associations include entirely different genera such as bass-
wood, hemlock and sugar maple. The latter do not occur in our designated
source area. Unfortunately, similar data do not exist for the Virginia side
of the Potomac, but the major species are more or less similar. The area
studied is approximately 40 percent forested. Pollen types are plotted in
Figure 23. ;
Deposition of Pollen in the Estuary
The first attempt was to assess whether there is a difference between
the channel and nonchannel zones of the river with respect to pollen depo-
sition. Out of the 20 channel samples analyzed, all contained sufficient
pollen grains to produce pollen assemblages while 19 out of 28 (68 percent)
of the nonchannel samples contained an adequate amount. An arbitrary number
of 5,000 to 10,000 grains per gram dry sediment was chosen as the minimum
amount of pollen upon which to compile an assemblage. In one case, 5,000 was
adequate because numerous types were present; in other cases 8,000 to 9,000
were considered inadequate because the assemblage included only one or two
types and the grains were broken.
grains were included in the study.
LAST
OFT:
*dbh r...diameter_at breast.height.
: : !
; 5.3/0- „
All samples containing greater than IU,UUU
'. !
1
|
! • —
!
; 1 . v.
m&s :.-£%
BOTTOM Of:
IMAGE AHEA
OUTSiD:
DIMENSION
FOR "A3LES
"AND ILLUS-
TRATIONS
-------
Figure 22. Locations of surface sediment transects for pollen distributions
in the Potomac River and locations of quadrangels used as the
vegetation source for the pollen.
-------
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1.8
6.6
2.7
T.5
1*8
9.5
I*4
2.1
32.7
3*5
V
•V
6.9
12*4
2.8
2.2;
2*3;
2J-
2*5
1.6;
i*
'i5:
7*r]
2*6;
5.0-
K
V:
4.2;
2.2:
Ji
1.4-
2.5;
2.7:
2.5;
11.4-
17.3-1
9.V
NO
Figur
tidal
-i ,'~\ — m
?°>l
£ w O -J
?. p, rn O •
.} i'*.' f)
^^B
NO POLLEN
IM^PII^^^
•»
NO POLLEN
•«••••
NO POLLEN
•^•M*
^^^••^^•^
•^••••^
^^•••HMB*
" NO POLLEN
i. io8
grelnt ptr gn
dry itdlmtnl
e 23. Di
stretch
—
NOP
NO P
^
NO P
~NO P
JLLEN
3LLEN
3LLEN
)LLEN
•
—
^
— —
-
'NO PC
NOP(
NO PC
"NO PO
LLEN
LLEN
LLEN
LLEN
™^~™
—
50% 50% 50% 50% 5% 5% 5% 5% 5% 5% 5% 5%
im PERCENTAGE OF TOTAL POLLEN (NOTE DIFFERENT SCALES)
-
~
5%
- ' .
5%
stributions of pollen types in surface' sediments throughout
of the Potomac River. * denotes channel samples.
the
-------
The next test was whether there is selective deposition of the tree •
pollen between channel samples and those nonchannel samples with adequate
numbers of pollen for the compilation of assemblages.
The results of a rank-sum test (Hollander and Wolfe 1973) performed for
each-tree pollen type, where the null hypothesis is that the percent of
total pollen of each type in the nonchannel samples is from the same popula-
tion as the percent of total pollen for each type in the channel samples,
indicates that percents of total pollen of hickory, beech, holly and cherry
are higher at the 0.06 significance level in the nonchannel samples. The
percent of total pollen of ironwood-hazelnut is lower in the nonchannel
samples at the 0.09 significance level. For the remaining types the null
hypothesis is accepted, i.e., there is no significant difference between
populations in channel and nonchannel samples.
The observation that only a few pollen types may be selectively
deposited, along with the consistent occurrence of large numbers of pollen
grains in the channel samples, indicates that the channel is the favorable
zone of deposition in the estuary for most pollen grains. Consequently, we
restrict all analyses relating pollen to vegetation to data from channel
samples.
The degree of similarity between pollen assemblages in the channel
samples when considering all of the identified pollen types from Tables 8 and
9 together, irrespective of their frequency of occurrence was next considered.
Table 10 shows Sorensen's similarity indices, which range between 0 (no
similarity) and 100 {complete similarity). For values greater than about 75,
the two samples may be considered replicates {Mueller-Dombois and Ellenberg
1974).
Since the index of similarity between all the channel samples taken
within the same transect (boxed values in Table 10) are greater than 75, it
is inferred that it is not necessary to take more than 1 sample at any one
transect. Furthermore, most of the similarity indices between samples from
Transects I through XVI and between samples from Transect XVI through XXVII
are greater than 75. Thus, taking only two samples, one in the vicinity of
Transect I - XVI and one in the vicinity of Transect XVI - XXVIII, would
yield a fairly adequate picture of the pollen assemblages in this stretch of
the river. Local effects, such as sporadic pollen input from the vegetation
or localized deposition, do not, to any great extent, mask the pollen repre-
sentation of the regional vegetation at any one locality and thus would not
mask regional changes in land use. Therefore, pollen in the tidal portion of
an estuarine depositional basin may provide an overall view of the regional
vegetation without the necessity of analyzing numerous samples.
The degree of similarity that occurs between samples taken at the same
location was then tested. Three sets of four samples were taken at ;
Transect VII by running the boat across the transect three times and attempt-
ing to sample each of the locations at the identical place each time. The
two triplicate samples taken in the nonchannel zone did not contain an
adequate number of pollen grains to analyze. The indices of similarity for
58 . . .. ._.
-------
TABLE 8. PERCENT OF TOTAL POLl
AREA OF ALL TREE SPECIES WITH >
i IN CHANNEL SAMPLES AND PERCEN^OTAL BASAL AREA IN THE DESIGNATED SOURCE
0,001 PERCENT BASAL AREA
tn
0.001% of total basal area are listed. Pollen cannot
be identified to species generally. Therefore a pollen type (qenus) can include species other than those
listed that occur outside of the designated source area.
and
wprp r.nmhinpri because the oollen is difficult to separate.
-------
Or TEX"
TABLE 9. PERCENT OF TOTAL POLLEN OF ALL SHRUB AND HERBACEOUS TYPES
Total pollen (%)
(n=20)
Scientific name
Ambrosia . —
Capri fo liaceae
Caryophy I laceae
Chenopodium
Cruciferae
Cyperaceae
Drosera
Equisetum
Ericaceae
Filicineae .
Galium
Gramineae
Jmpatiens
Leguminosae
Ligustrum
Ligu lifloreae
Lonicera
Lycopodiim t-i
Myriophyllum
Nympheaceae
Osmunda
Plantago
Polygonaceae
Potamogeton
Popov eraceae
Primulaceae
Ranunculaceae
Rhamnus
Rhus
Rosaceae
Rumex
Sambucus
Saxifragaceae
Salix
Solanaceae
Solidago
Sphagnum
Tubuliflorae
Typha
Vmbelli ferae
Urtica
Vaccinium
Viburnum
^Violaceae
Zed
• ! •g ,
Common name
ragweed
honeysuckle family
pink family
pigweed
mustard family
sedge family
sundew
horsetail
heath family ;
ferns
bedstraw
grass family
_ . jewel weed ... ... _..
legume family
privet
composites '-,
honeysuckle
3 ' club moss
milfoil
water-lily family
flowering fern
plantain
buckwheat family
pondweed i
poppy family [
primrose family \
buttercup family
buckthorn
sumac
rose family
sorrel •
el derberry
saxifrage family
willow
nightshade family
goldenrod
sphagnum moss
composites
cattail
parsley family
nettle
blueberry
viburnum
violet family
corn
.-. .-. . . .-
; ;x:x;x;x60
r r e^ucin-y MI —
channel samples (%)
100 . -
5
10
100
45
50
5
5
15
30
5
100
1 5
25
45
20
5
25
40
10
10
100
30
15
5
10
25
60
35
45
85
5
5
85
15
5
40
75
45
55
5
5
15
20
15
Mean
-16.1
0.02
0.02
1.0
0.2
0.17
0.01
0.01
0.04
0.2
0.01
5.0
0.07
0.09
0.2
0.9
0.015
0.06
0.14
0.05
0.025
1.0
0.18
0.04
0.01
0.1
0.09
0.3
0.15
0.4
0.7
0.03
0.015
0.5
0.06
0.02
0.11
0.6
0.2
0.2
0.02
0.01
0.03
0.16
0.05
S.D.
- 4.5
0.09
' 0.06
0.3
0.3
0.2
0.04
0.04
0.11
0.35
0.04
3.3
0.2
0.16
0.3
3.6
0.07
0.1
0.3
0.11
0.08
0.5
0.3
0.09
0.04
0.5
0.17
0.4
0.2
0.5
0.5
0.13
0.07
0.4
0.16
0.09
0.15
0.5
0.2
0.2
0.09
0.04 BOTTOM OF
0.07 IMA(^E A!—
0.4 ' OUTSIDE ^
0.13 ^••'"Eil'2iOI<-i
. .I 1 Ai-.i !->.
^.!":3 i L-L'.J-L'.'-
! "RATIONS
PAGi}
-------
TABLE 10. MATRIX OF INDEX OF SIMILARITY IN PERCENT FOR CHANNEL SAMPLES
(INDEX OF SIMILARITY = 2W/A+B, WHERE A = SUM OF ALL VALUES OF PERCENT OF TOTAL POLLEN FOR ALL TYPES,
: B = SUM OF ALL VALUES OF PERCENT OF TOTAL POLLEN FOR ALL TYPES IN SAMPLE BEING COMPARED. W = SUM OF
I SMALLER OF THE TWO VALUES OF THE PERCENT OF TOTAL POLLEN FOR ALL TYPES IN THE TWO SAMPLES BEING COM-
' PARED. BOXED VALUES INDICATE THAT THE INDEX OF SIMILARITY IS BETWEEN SAMPLES TAKEN IN THE SAME
: TRANSECT.)
00
CM
I
co
I
Sample
1-2
III-2
V-2
VII-2
VII-3
X-2
XII-2
XV I -2
XVI-3
XVII-2
XV 1 1 -3
XIX-8
XX-2
XXIII-8
XXVI-2
XXVI-3
XXVI-4
XXVIII-2
XXVII 1-3
XXXVI 1 1 -4
CM
1
»— i
94
90
76
79
79
78
75
72
66
62
64
69
66
58
66
65
58
67
57
.9
.6
.2
.5
.6
.7
.6
.1
.1
.9
.5
.8
.0
.1
.5
.9
.2
.6
.0
CM
1
i— <
1— 4
1— 1
77.2
61.5
65.3
62.9
60.2
62.7
55.5
61.9
58.1
63.0
63.7
55.6
60.3
47.9
59.8
64.2
54.1
59.1
CM
1
S>
71
76
73
69
72
66
65
64
60
68
64
62
62
65
61
48
60
.5
.8
.2
.8
.7
.9
.8
.8
.5
.3
.3
.4
.5
.3
.7
.7
.6
CM
1
i— i
i— i
>•
86
81
78
77
71
73
70
69
72
66
64
66
67
62
64
65
.0
.4
.0
.0
.4
.0
.0
.4
.0
.3
.5
.2
.9
.0
.2
.8
CO CM CM CO 1 1 CO f-i |
•-* li-i>;>>>H-ixxx
>xxxxxxxxxx
Sample 2A 2B .
2A
2B 79.6
87.1 2C 78.9 84.0
82.6 84.5
82.7 83.4 88.5 3A
75.7 77.7 83.4 84.4 3B
75.2 73.7 79.8 79.1 76.2 3C
70.8 68.9 74.4 75.5 76.2 80.3 Index of
71.9 71.9 77.0 78,2 79-2 77.2 76.5 for triplicate
77.9 78.2 82.9 86.1 81.5 81.6 77.6 82.9
72.0 74.7 81.5 81.2 82.8 72.4 78.5 79.4 83.2
65.1 66.7 70.6 63.3 72..6 74.4 84.8 81.4 80.6 81.5
73.1 73.8 81.1 83.6 87.6 76.3 77.7 80.1 84.1 77.1 76.8
76.3 74.6 80.1 83-9 84.0 80.6 80.2 82.2 84.7 85.9 82.6
66.4 66.1 72.1 74.2 74.7 78.4 76.9 78.6 80.7 81.3 79.4
70.3 72.3 78.7 80.2 81.8 74.2 85.0 78.1 79.1 87.1 83.6
64.6 65.5 71.2 73.8 78.4 76.2 84.2 76.9 80.3 81.1 88.4
\ • i
\
X
X
2C
•xi
>
X
X
i— i t— i i— <
>• >• >
XXX
XXX
3A 3B 3C
79
78
similarity
sampl
87.7
78.7
84.8
79.2
es at
'83.4
85.7
82.6
.4
.1 88.6
in percent
Transect VII
75.9
78.4 84.2
-------
the triplicate samples at the two channel locations are all greater than 75
(see Table 10), indicating that the data from one sample at a location may be
representative of the pollen assemblage at spot.
Relationship Between Pollen in Sediments and Source Area
- Only tree species were used in analyzing relationships between pollen
assemblages and source vegetation because the vegetation data are restricted
to tree and shrub species.
In order to estimate the areal extent of the source vegetation, the ob-
servation was made that the distributions of the pollen of maple (other than
red maple, the pollen of which is easily distinguishable from other species),
basswood and hemlock occur in very low frequencies in the pollen assemblages.
These trees are not present in the area chosen as the source vegetation
(Table 8). This indicates that pollen is not being transported into the tidal
Potomac from the Upper Potomac which drains the Appalachian province in
Maryland where sugar maple constitutes approximately 35 percent of large for-
ested areas, hemlock approximately 17 percent, and basswood approximately
7 percent (percent basal area of total basal area of these particular associ-
ations). Maple pollen, not identified as red maple, probably represents sil-
ver maple which grows on floodplains in the area studied. Although sediments
have not been sampled in the Upper Potomac in the vicinity of the sugar
maple - basswood and hemlock - birch forests, sediments from the Upper
Chesapeake Bay draining similar forest regions in Pennsylvania (via the
Susquehanna River) contain large amounts of maple , hemlock, and birch pollen
(described later in this section). In the Potomac sediments, birch pollen
occurs in low numbers, although consistently, comparable to the percent basal
area of river birch growing along the river. Thus the pollen occurring in
the sediments appears to represent fairly closely the vegetation of the area
chosen as the source. This provides justification in the expectation that
the vegetation of the study area bears some relation to the pollen in the
sediments, and it would constitute the area where changes in the vegetation
due to land use would be reflected by changes in the stratigraphic pollen
assemblages. ;
I Tables 8 and 9 listed all of the pollen types occurring in the channel
samples with their frequency of occurrence and percents of total pollen. Per-
cents basal area for each tree species greater than 0.001 percent of total '
basal area are listed. Frequency of occurrence and percents of total pollen
of shrub and herbaceous pollen are listed in Table 9. Total grains per gram
dry sediment and percents of total pollen of pollen types occurring in at ;
least 90 percent ofthe channel samples are plotted on Figure 23. i
\ .. \ \
\ Except for tulip poplar and sweet gum, there is a reasonably close cor- ;
respondence between percent basal- area of many of the species occurring in }
the source area and percent of total pollen of respective pollen types in the
sediment. Some of the less abundant trees are over and underrepresented • sorrow Of
!(Table 8). The result is surprising in the light of differential pollen pro- IMAGE ARE
duction both between and within tree types and the differential transport arod OUTSIDE
-deposition of pollen grains (Brush and Brush 1972, Davis, Brubaker and -
Beiswenger 1971). -A comparison of these values with those shown-for .other ,_ NJ*TABLES
;D ILLUS-
-------
depositional environments (e.g., Davis and Goodlett 1960, Livingstone 1968,
Crowder and Cuddy 1973) indicate that R-values (pollen-tree ratios) are rela-
. : ted strongly to depositional environment as well as to pollen production. The
.•'.:.".'--. generally lower standard deviations for the mean percents of total basal area
. are an indication that the mixing process, either in the river or in the at-
mosphere or in both, smoothes out the variability in the pollen distributions
compared to the distributions of the trees. _
Next the spatial variations in the total number of pollen grains per
gram dry sediment and percents of the tree pollen were compared with the
spatial variation in total basal area and percents basal area of the respec-
tive trees to observe whether similar gradients corresponded in the tree types
and their respective pollen types. A gradient is considered a true gradient
if both the t-value and the correlation coefficient are significant. Table 11
presents results from regressions of total number of pollen grains per gram
dry sediment and percents of total pollen for the tree species present in the
channel samples. There is no significant correlation between distance down-
stream and total number of pollen grains per gram dry sediment or on percents
of beech, ironwood-hazelnut, birch, hickory, blackgum, oak, walnut, red cedar,
dogwood, holly and cherry, while there is a significant correlation for per-
cents of elm, ash, sycamore, sweet gum, maple, red maple and pine. The
t-values for the latter types show that distance does have an effect on the
percent of total pollen (the slope of the lines is different from 0). Ac-
cording to the slopes of the regression lines, the distance effect is slightly
negative (percent of total pollen decreases with distance downstream) for elm,
ash, sycamore, maple and red maple, slightly positive (percent of total pollen
increases with distance downstream) for sweet gum, and relatively much more , :
pronounced in the positive direction for pine.
' Table 12 shows the results from regressions of mean total basal area and
percents of total basal area of each tree type for each latitudinal section .
on longitudinal distance from north to south, and it shows the regressions of
mean total basal area and percent of total basal area of each tree type for
each longitudinal section on latitudinal distance from west to east. These
mean values are presented with their standard deviations and numbers of obser-
vations in Table 13. There is no observable trend, i.e., significant t-value
and correlation coefficient, in the vegetation in either the latitudinal or
longitudinal direction except for pine which increases relatively greatly
from north to south, sweet gum which increases slightly from north to south,
hickory which decreases slightly from west to east, and red cedar which
decreases from west to east and increases from north to south, in .both cases
very slightly. The southward increase of pine and sweet gum in the vegetation
is observed also in the pollen distributions (Figures 24 and 25) but the
eastward decrease in hickory and red cedar is not present in the pollen dis-
tributions because the gradients in the vegetation probably are very slight.
The differences that appear in the pollen assemblages of all other types which
Show no vegetational gradient must be attributed to the differential effect of
transport and depositional processes, j | BOTTOM OF
i | ! . ! IMAGE ARE
CEGiN J I I j OUTSIDE
LAST LiS'-lc: ! j • j njMCMcir-^
OF TEXT -J-__ j I ! pcJffTABLES
,-,,,,,., J,,,,,,,,. '">AND iLLUS-
V m^63":'-::M ! TRATICM?
-------
TABLE 11. REGRESSION OF PE'RCENT OF TOTAL POLLEN {.y) IN THE SURFACE SEDIMENTS
(n=20) ON DISTANCE DOWNSTREAM IN NAUTICAL MILES (x)
Total pollen
grains per gram
dry sediment (%)
Acer
Acer rubmm
Betula
Carya
Carpinus - Corylus
Cornus
Fagus
Fraxinus
Hex
Juglans
Juniperus
Liquidambar
Nyssa
Pirtus
Platanus
Prunus
Quercus
Ulmus
Correlation coefficient is
tt-value is significant at
sion line is significantly
•[correlation coefficient is
St-valup is sianifirant. at
«
Regression Equation
y = €1426.8 + 222.8 x
y = 1.14 - 0.013 x
y =0.43 - 0.005 x
y = 3.79 - 0.002 x
y = 2.45 + 0.001 x
y = 0.92 + 0.004 x
y = 0.05 + 0.00006 x
y = 0.29 + 0.001 x
y = 2.97 - 0.034 x
y = 0.05 + 0.001 x
y = 0.905 - 0.002 x
y = 0.26 + 0.004 x
y = 0.392 + 0.015 x
y = 0.16 + 0.0004 x
y = 9.16 + 0.22 x
y = 5.01 - 0.05 x
y = 0.08 + 0.0008 x
y = 24.10 '+ 0.05 x
y = 3.62 - 0.039 x
significant at 0.05 level
0.01 level indicating that
different from zero
significant at 0.01 level
O.fl5 IPVP! . ...
r
0.182
-0.473*
-0.564|
-0.223
0.017
OJ51
0.014
0.103
-0.608+"
0..245
-0.198
-0.255
0.527*
0.042
0.844I
-0.713!
0.092
0.324
-O.SOO+"
the slope of the
t-value
1.45
- 3.55+
- 5.23t
- 0.30
0.19
1.17
0.11
0.63
- 6.06t
1.77
1 .28
2.06
4.98+
0.37
12.32t
- 7.98t
0.76
2.67§
-10.23+
peg res -
: '..., ,.,;J ."-..-
•64
-------
TABLE 12. REGRESSION OF MEAN BASAL AREAS IN LATITUDINAL AND LONGITUDINAL SECTION (y) IN THE VEGETATION ON
DISTANCE OF SECTION FROM NORTH TO .SOUTH OR WEST TO EAST IN MILES (x)
Ul
Regression equation
\ of mean basal areas
| in longitudinal sections
i Total basal
area (%)
(cm§)
Acer
Acer rubrum
Betula
Carya
Carpinus - Cory lus
Cornus
Fagus
Fraxinus
Hex
Jug Ions
• Juniperue
Liquidambar
Nyssa
Pinus
Platanue
Prunus
Quercus
Ulmus
on distance from
west to east (n=9\
y = 11078.4 + 1.7 x
y = 0.95 - 0.008 x
y =4.46 + 0.023 x
y = 2.26 - 0.007 x
y = 7.56 - 0.152 x
y = 0.118 + 0.022 x
y = 0.56 + 0.009 x
y = 2.43 + 0.012 x
y = 0.73 - 0.0002 x
y = 3.87 - 0.042 x
y = 0.004 + 0.001 x
y = 0.57 - 0.010 x
y = 7.54 + 0.024 x
y = 6.35 - 0.063 x
y = 6.12 + 0.303 x
y = 1.15 - 0.011 x
y = 0.56 - 0.004 x
y = 40.58 - 0.068 x
y = 0.438 + 0.026 x
r
0.018
-0.100
0.153
-0.069
-6.36*
0.490
0.310
0.093
-0.005
-0.512
0.274
-0.599*
0.100
-0.266
0.569
-0.160
-0.188
•-0.114
0:262-
t-value
0.09
-0.50
0.76
-0.33
-4.03t
2.76f
1.54
0.46
-0.02
-2.91-t
0.08
-3.64t
0.49
-1 .34^
3.371=
0.83
-0.90
-0.01
1.32
Regression equation
of mean basal areas
in latitudinal sections
on distance from
north to south Jn=10)
y = 10928.0 + 9.3 x
y = 1.83 - 0.026 x
y = 5.53 - 0.014 x
y = 1.91 + 0.029 x
y = 1.88 + 0.002 x
y =0.38 + 0.012 x
y = 1.39 - 0.012 x
y = 4.30 - 0.035 x
y = 1.45 - 0.014 x
y = 0.81 + 0.028 x
y = 0.02 + 0.0002 x
y = 0.004 + 0.003 x
y = 5.39 + 0.089 x
y = 3.38 + 0.020 x
y = 2.53 + 0.378 x
y = 0.63 + 0.010 x
y = 0.34 + 0.002 x
y = 35.61 - 0.051 x
y = 1.52 - 0.009 x
r
0.176
-0.392
-0.16
0.191
0.037
6.272
-0.462
-0.291
-0.312
0.454
0.058
0.547*
0.572*
0.246
0.732§
0.207
0.106
-0.169
-0.153
t-value
-1.68
-2.23
-0.60
1.04
0.19
1.48
-2.7&
-1.61
-1.68
2.64t
-0.02
-3.24t
3.68t
1.37
5.64t
1.08
0.60
-0.90
0.83
Correlation coefficient is significant at 0.10 level
tt-value is significant at 0.01 level, indicating that the slope of the line is different from zero
rt-value is significant at 0.05 level
§correlation coefficient is significant at 0.05 level
-------
TABLE 13. MEAN TOTAL BASAL AREAS AND MEAN PERCENT BASAL AREAS IN THE VEGETATION
BY LATITUDINAL SECTION
Quad Nos. In each
latitudinal section
1-3
4-8
9-11
12-16
17-21
22-27
28-35
36-39
40-42
43
Distance of section
north
No. of
to south 1n miles
plots
Mean total basal. area (cm2)
Mean %
Mean *
Mean %
Mean %
Mean %
Mean %
\
\
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
Mean %
S. D.
Acer
S. D.
Acer rubrum
S. D.
Be tula
S. 0.
Carya
S. D.
CarpinuB-Cory lua
S. D.
Comua
S. D.
Fogua
S. D.
Froxinus
S. D.
JZar
S. D.
Juglans
S. D.
eftmiperue
S. D.
Liquidambar
S. D.
Nyssa
S. D.
Pinws
S. D.
Platnus
S. D.
PrtmKG
S. D.
§ucrcus
S. D.
Ulmua
S. D.
0
5
8172.8
2657.2
-0-
-0-
2.8
2.2
-0-
-0-
0.4
0.9
-0-
-0-
1.6
3.6
-0-
-0-
-0-
-0-
1.4
2.2
-0-
-0-
-0-
-0-
2.0
4.5
5.8
11.3
5.0
8.3
-0-
-0-
-0-
-0-
47.7
46.5
-0-
-0-
8.7
18
12399.9
4075.2
4.9
20.8
2.6
5.4
2.3
6.9
1.0
2.0
0.1
0.2
6.7
1.1
1.6
6.1
0.1
0.2
0.6
1.5
-0-
-0-
-0-
-0-
8.4
15.1
2.5
3.4
18.7
27.3
0.2
0.7
0.9 '
3.3
43.4
32.3
0.2
0.7
17.4
12
11125.5
5214.2
-0-
-0-
10.6
18.3
5.8
17.8
1.8
3.3
0.2
0.6
1.5
2.0
4.5
15.3
2.4
6.3
0.8
1.4
-0-
-0-
-0-
-0-
4.2
5.9
3.0
4.2
5.9
17.8
0.2
2.3
0.3
u.6
19.6
32.1
0.8
2.3
26.1
16
12415.8
4153.7
-0-
-0-
1.9
3.4
0.6
2.3
4.9
10.7
0.3
0.7
0.4
1.6
9.9
16.7
3.0
8.0
0.1
0.5
-0-
-0-
-0-
-0-
12.7
17.2
4.5
8.5
9.3
16.0
0.8
3.3
-0-
-u-
26.5
28.7
4.8
13.0
34.8
16
12787.4
5531.8
3.2
12.5
7.6
8.4
5.2
18.5
1.2
2.5
2.9
9.2
0.4
0.9
4.9
10.7
2.3
6.5
2.4
6.3
-0-
-0-
0.1
0.3
8.8
13.0
4.4
8.2
3.7
7.5
3.8
8.5
-0-
-u-
28.1
25.6
1.7
3.7
43.5
24
11881.4
3074.5
-0-
-0-
6.0
9.7
3.4
11.1
2.3
4.2
0.4
1.2
1.0
1.7
4.8
9.1
-0-
0.2
2.6
6.9
0.3
1.2
0.3
0.9
7.1
13.5
2.1
3.0
19.2
30.8
0.4
1.8
0.8
t.l
33.4
29.9
2.6
10.8
52.2
20
10694.4
3605.9
-0-
-0-
7.9
13.7
-0-
-0-
3.6
6.0
0.9
2.0
2.0
3.3
2.4
5.5
1.1
3.7
' 2.7
3.4
-0-
-0-
0.3
0.6
9.9
13.8
2.1
3.5
17.6
25.0
-0-
-0-
1.2
4.1
33.3
26.6
0.9
3.6
60.9
12
11407.5
2653.4
-0-
-0-
6.3
7.7
0.6
2.0
2.7
5.6
3.1
7.0
1.2
2.0
1.3
2.9
-0-
-0-
3.6
3.3
-0-
-0-
0.2
0.4
13.6
17.5
4.4
4.5
25.2
28.1
2.7
5.9
0.1
0.3
33.4
22.0
0.7
2.3
69.6
8
9988.3
2537.2
-0-
-0-
4.0
5.3
12.4
25.2
1.7
4.5
0.6
1.5
-0-
-0-
-0-
-0-
-0-
-0-
5.1
4.2
-0-
-0-
0.4
1.1
14.9
14.8
3.1
3.6
18.9
23.1
1.7
5.0
0.8
1.4
38.7
32.4
-0-
-0-
78.3
1
12051.0
—
-0-
—
-0-
-._
-0-
-0-
_-_
-0-
-.--
-0-
_.-
-0-
._.
-0-
-0-
—
-0-
_--
-0-
__.
7.0
...
9.0
--_
50.0
—
-0-
—
-0-
32.0
—
-0-
. . . ---
(Continued)
-------
TABLE 13 (Continued)
t-
co
S
Quad Nos. 1n each
longitudinal section
Distance of section
west to east In miles
Number of Plots
Mean total basal area (cm2)
S. D.
Mean % Acer
S. D.
Mean % Acer rubrum
S. D.
Mean % Betula
S. D.
Mean % Cory a
S. D.
Mean 55 Carpinua -Cory TUB
S. D.
Mean % Cornua
S. D.
Mean % Fagua
S. D.
Mean % Froxinua
S. D.
Mean % Ilex
S. D.
Mean % Juglana
S. D.
Mean % Juniperua
S. D.
Mean % Liquidambar
S. 0.
Mean % %eea
S. D.
Mean % Pinua
S. 0.
Mean % Platanua
S. D.
Mean % Primus
S. D.
Mean % Queroue
S. D.
Mean % Ulmua
S. D.
BY LONGITUDINAL SECTION
28
0
1
7492.0
. —
-0-
...
1.0
—
-0-
...
15.0
—
-0-
.--'
-0-
-0-
-0-
6.0
...
-0-
...
1.0
-0-
-0-
_--
1.5
—
1.0
0.0
-0-
58.0
—
-0-
.
22,29
6,8
6
12858.0
2755.3
-0-
-0-
2.3
2.9
-0-
-0-
2.2
5.3
0.2
0.4
0.8
2.0
0.2
0.4
0.8
2.0
2.5
2.9
-0-
-0-
0.2
0.7
11.0
19.7
1.8
2.1
16.5
16.6
-0-
-0-
1.3
3.3
45.0
35.1
-0-
-0-
12,17,
23,30
13.6
10
12924.9
2991.9
-0-
-0-
7.7
9.0
4.2
12.3
1.6
4.1
0.2
0.6
0.8
1.1
3.9
10.8
0.1
0.3
3.9
7.7
-0-
-0-
0.4
0.8
14.1
11.9
2.1
3.1
13.7
25.1
3.3
2.8
0.1
0.3
-v 29.0
29.2
0.2
O.G
4,13,18
24,31
20.4
16
10838.1
4559.6
3.2
12.5
9.8
16.5
4.6
11.7
3.7
9.8
o;8
1.6
0.7
1.6
6.0
14.5
2.4
6.6
1.9
6.8
-0-
-0-
0.1
0.3
5.8
8.0
1.8
2.0
5.7
9.3
2.0
8.6
0.5
1.4
28.3
30,8
-0-
-0-
5,9,14,19
25,32,36
27.2
26
12905.4
5118.7
3.4
17.5
5.0
16.1
3.8
14.6
2.4
4.5
0.5
1.3
1.2
1.8
. 3.0
7.9
0.4
1.6
2.0
4.5
-0-
-0-
0.2
0.8
10.1
14.5
5.3
8.1
17.3
26.9.
0.1 •
0.6
0.5
2.2
29. 0.
26.2
3.8
6.9
1,6,10,
15,20,26,
33,37
34.0
29
11421.4
3890.2
-0-
-0-
6.7
12.6
2.5
11.6
2.3
5.0
1.3
6.9
. 0.8
1.5
6.1
12.6
0.7
3.9
0.5
1.2
-0-
-0-
0.5
0.5
8.3
17.4
3.1
4.3
17.4
27.4
0.5
1.9
0.6
2.6
35.3
29.2
1.6
5.5
2,7,11,
16,21,27,
34, "38, 40
40.8
31
11106.6
3240.3
-0-
-0-
4.1
6.6
2.9
12.6
1.8
3.9
0.8
3.0
1.3
2.7
3.6
9.1
2.1
6.5
2.3
3.3
0.2
1.1
-0-
-0-
8.2
11.2
3.3
6.4
15.9
25.9
1.9
5.0
0.7
3.3
28.9
30.1
4.7
13.4
3,8,35,
39,41
47.6
11
10028.6
3083.5
-0-
-0-
6.2
8.6
0.6
2.1
1.9
3.7
2.6
6.3
1.7
2.8
2.0
6.6
-0-
-0-
3.0
4.3
-0-
-0-
0.3
0.9
12.7
16.9
1.3
1.5
6.4
9.9
-0-
-0-
0.3
0.9
48.2
30.2
-0-
-0-
3
42,43
54.4
2
10553.5
2117.8
-0-
-0-
3.0
4.2
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
-0-
2.5
3.5
-0-
-0-
-0-
-0-
3.5
5.0
8.0 .
1.4
35.5
20.5
-0-
-0-
-0-
-0-
47.0
21.2
-0-
-0-
-------
o r~ no
-p. > rn
-i '.<\ 9
m ' z
x r~
50r
;:.- 00;
CO • •'
!;H l.:-:.
30r
^20
tfi
z
a
^ 10
16
32
48 64 60
DISTANCE (km)
96
113
129
IB
Figure
36 54 72 90 108
DISTANCE DOWNSTREAM (km)
area in
126
144
162
Percent pine of total
distance with 95 percent confidence intervals.
versus latitudinal and longitudinal
Figure:;24b~ Percent pine of total pollen in channel samples versus distance downstream.
.;'•• ;••• :rj 51' .;.. j> ~i
::1 l- ...< rij oi C"> ^
9 P iS ^ R ^ S
-------
O r- co
=71 > rr»
30 n
16
32
46 64 80
DISTANCE (km)
96
113
T29
1
i '.
1..'
Iv
1: ' fc
••: «»
;;; I
a
.8-
a
2
IB
36 54 72 90 108
DISTANCE DOWNSTREAM (km)
126
144
162
Figure 25a. Percent sweet gum of total basal area in vegetation versus latitudinal and longitudinal
distance with 95 percent confidence intervals. (No significant difference exists for
percent sweet gum versus longitudinal distance.) j i
Figure, 25b. Percent sweet gum of total pollen in channel samples versus distance downstream.j .
r) ° ^ ci] c/i p ^
-------
Effect of Transport on Pollen Distributions
The distance a pollen grain is transported in an estuary is dependent
upon the depth of the water, the degree of turbulence in the water column,
and the settling properties of the pollen once it enters the water. For a
river such as the Potomac, it is assumed that turbulence immerses the pollen
completely within a few meters of downstream transport. Once immersed, pol-
len will behave like similar particles with small Reynolds numbers and fal-
ling within the range of Stokes law of resistance. Some differentiation is
to be expected because size and specific gravity differ among pollen types,
not all grains are spherical and size and shape can change with immersion
(Brush and Brush 1972). Based upon the behavior of small particles in tur-
bulent flow (McNown et al. 1951, Brush 1965) and data obtained from a labora-
tory study of pollen transport in a small sediment-laden flume (Brush and
Brush 1972), some interpretations were made regarding the effect of transport
on pollen distributions in the Potomac surface sediments.
. i . -
I The effects of transport were identified by the selective deposition of
pollen types in channel and nonchannel sediments and by the value of the .cor-
relation coefficient for percent of total pollen versus distance downstream. ~
A high correlation coefficient indicates less scatter in the data than a low
regression coefficient. A lot of scatter means that very little dispersion
of the pollen has occurred and the pollen is deposited close to its source
or that differential deposition is operating after the pollen becomes mixed ;
in the water column resulting in a secondary uneven distribution.
| Correlation coefficients for percent of total basal area with latitu- ;
dinal and longitudinal distance are low for all species of trees indicating I
that distributions of the source vegetation are highly uneven or patchy. !
This is an accurate description of tree distributions because individuals of
a species occur most commonly as stands or in more or less discrete clumps.
Therefore, pollen distributions with low correlation coefficients are re-
flecting the local patchiness of the tree distributions, whereas those with
high correlation coefficients have had the vegetational patchiness erased i
from their distributions by dispersion. |
i I i . ;
Five types of transport behavior are recognized in the distributions of ;
pollen described here: i i
; I
1. Hickory (40-45 y), beech {40-45 y), cherry (25-30 y) and holly (25- !
;30 y) occur more frequently in the nonchannel samples and show insignificant ;
correlation coefficients. Once introduced into the river, it appears that j
jthey settle quickly and are deposited in shallower water. There is no infor- ;
mation available on the settling velocities of these grains. 1
I 2. Oak (25-30 y), black gum (30-35 y), walnut (35-40 y), dogwood (35-
|40 y) and red cedar (25-30 y) occur nonselectively in channel and nonchannel I
jsamples and show a lot of scatter. They are not transported far in the ] nQTT0..., r>-
'water bef.ore being deposited. Atmospheric transport may ensure their even i ^QC"AREA
BEGIN distribution across the channel. Once in the water they settle rapidly. Oak;' ouTSiCiE'""
LAST LiiiF has a specific gravity of 1.2 which does not indicate a high settling velo-._4 DIMENSION
OF TEXT .- 'city relative._to many pther_pol 1 en types. .Qbj€ry_ati_pjTs_fjD.r_o_ak_are_J_n J FOR TABLES
! A ^/8" ^ :-:-:-:-x-:----i---:-x-x-x- '"'-*• AND ILLUS-
! . 7 " ' ? :::S:;^:70 Vi^Vi ] TRATIONS
-------
REGir
LAST
OFT
agreement with laboratory results where only 2 percent of the oak pollen load
remained in suspension 15 minutes after entry into the water column (Brush
and Brush 1972). The behavior of oak in the experimental study contrasted
strongly with other pollen types which remained in suspension in much greater
numbers and therefore for a longer period of time. The settling properties
.of red cedar pollen erase from the pollen distributions the very slight
gradients that appear in the distributions of the trees.
3. Ironwood-hazelnut, with an average size of 30 y, were selectively
deposited in the channel sediments where the water is deeper. However, the
data contain a lot of scatter indicating that although deposition occurred
in the deeper water, the pollen grains did not remain in suspension very long
and are probably deposited close to their entry. In. the previously mentioned
laboratory study, hazelnut occurred in fairly large numbers in the bed al-
though not nearly approaching the deposition rate of oak.
'• 4. Maple (40-50 y), red maple (49 y), ash (38-41 y), elm (37 y), and
sycamore (19-22 y) are deposited nonselectively in channel and nonchannel
sediments. They show less scatter than the previously discussed grains indi-
cating that they are deposited evenly and may be transported a greater dis- -
tance. They decrease in frequency in the downstream sediments because they
probably remain suspended in this part of the river where the water is deeper
and more turbulent.
; 5. The pollen type most affected by transport is that of birch (30 y).
It occurs in both channel and nonchannel samples and shows virtually no scat-
ter indicating that it remains in suspension for a long period of time and is.
totally dispersed before being deposited. This observation agrees with the
previous laboratory observation where 71 percent of the birch pollen load
remained in suspension 15 minutes after entry into the water column. In
that study it was observed also that the size and shape of birch changed with
immersion in such a way as to decrease its settling rate.
i ,
j It is inferred from these results that transport processes disperse the
pollen to a greater or lesser degree depending upon the physical properties
of the individual grains. Thus, transport and selective deposition of pollen
'serve to erase, for some tree types more than for others, some of the patchy
characteristics of tree distributions without altering the pollen assem-
blage's representation of the regional vegetation.
i I i
Conclusions ,
j !
i 1. Adequate amounts of pollen for compiling pollen assemblages are
obtained more frequently in channel as opposed to nonchannel sediments in
the tidal Potomac River. The results are reproducible at any one location.
For an overall view of the pollen assemblages in the tidal Potomac, it is
necessary to obtain only two samples, one located in the upper region of the
tidal river and the other close to the mouth. i
i ! 2. The pollen in the channel surface sediments are, for the most part, j
LI; .^'representative of the adjacent vegetation. All types abundant in the vege-. \
tation appear in the pqlTen assemblage except tulip poplar. In spite of |
t;-. i
BOTTOM OF
IMAGE AREA:
CUTSiDS
DIMENSION
FOR TABLES
•ANO ILLUS-
TRATIONS
-------
Gh- TEX
differential productivity and transport for different pollen types, there is
a fairly good correspondence between percents of total basal area and per-
cents of total pollen with a few types being under- or overrepresented in
the pollen. The southward increase in pine and sweetgum in the vegetation is
reflected in the pollen assemblages of the surface sediments, while the west-
ward decrease of hickory and the westward decrease and southward increase of
red cedar are too slight to be_recorded in the pollen distributions.
3. Transport processes in the atmosphere and water erase some of the
localized patchy distributions of the vegetation types from the pollen dis-
tributions. The degree to which this occurs is related to the physical
characteristics of each type of pollen grain.
4. Since the estuarine processes reduce local noise in the pollen dis-
tributions without obliterating representation of regional gradients in the
vegetation, this depositional environment is considered useful for stratig-
raphic work. ;
j j ;
VERTICAL DISTRIBUTIONS OF POLLEN IN -ESTUARINE SEDIMENTS '
With respect to the dating of stratigraphic horizons for determining
sedimentation rates, this study concentrated on establishing rates in the
Upper Chesapeake Bay. Therumber of horizons that can be dated from a core
depend upon the time interval covered by the core and the number of land use
and vegetation changes during that time interval that are of a sufficient
scale both in area affected and in intensity to be reflected by changes in
pollen assemblages. As indicated earlier, localized changes are likely to
be masked by the regional condition. ;
i
• Two cores from the Susquehanna Flats (SF-2 and SF-3) were analyzed and
two (FB-I and FB-II) in detail and one (FB-III) partially from Furnace Bay
(see Figures 2 and 3 for locations of cores). .The two cores from Susquehanna
Flats contained very low concentrations of pollen; consequently, these analy-
ses were not continued for this study. ; It appears from the counts made that
by concentrating the pollen extracted from the samples (see Quality Assurance
Report), it may be possible to obtain sufficient data to compile vertical
profiles showing changes in the assemblages. This investigation is proceed-
ing. The cores from Furnace Bay contained well-preserved pollen in suffi-
jcient numbers to provide sedimentation rates for different time intervals.
I In cores FB-I and FB-II, all pollen types were identified; Figures 26
•and 27 have been plotted with only those types that provide information re-
garding sedimentation rates. In core FB-III, only the oak and ragweed pollen
were identified in order to identify the agricultural horizons.
\ • I i
Furnace Bay Core Number I (Figure 26) —
j This core is 96 on long and consists of silt and clay throughout. The
top 79 cm are dark grey while the zone from 79 to 92 cm is a light brownish
grey. Darker colored bands occur at 6 to 7 cm, and brown bands were observed
— !at 22 to 23 cm, 30 to 31 cm and 39 to 40 cm. The top 8 cm has a higher water
1 content than the.remaindermen the core. ;
BOTTO
IMAGE
OUTSi
M OF
AREA:
DE -
J FOR TABLES
>AND ILLUS-
i TRAT!ON>
-------
o*
£
o
-"40
a
ui
o
80
96
POLL
..
5 x I04 I
no. grains per
gram dry sediment
EN
-— 1978^,
0.6 cm/yr
-— '1930
0.6 cm/yr
1820
10% 50% 25%
ASSUMING A0.6cm/yr SEDIMENTATION RATE
H-
2
UJ
5x I03
5xl03
L
OAK
RAGWEED
b. - •,
w^g, 5xl03
£0!°"
30
zu
^ lOxlO2
O
a.
UI
r PINE
1 , , >t-xx> ^_^ ,
T . HEMLOCK
III ^*^**>^ .— i*^! *. «* I
1600 1700 1800 1900 2000
TIME IN YEARS
Figure 26. Stratigraphic pollen profile of Core I from Furnace
Bay and the flux of pollen of oak, ragweed, pine
and hemlock.
73
-------
BEGIN
LAST L
OF TEX
Total pollen per gram dry sediment fluctuates considerably between
levels. Except for a zone of no pollen between 40 and 50 cm, pollen con-
centrations are fairly high throughout.
The oak-ragweed ratio, an indicator of clearing of forests for agri-
culture, remains less than 1 throughout the core except for the bottom 2 cm
where it reaches 1.8. This large increase in oak pollen indicates that at
the time the area was mostly forested with some local clearing. Historical
records show that at Furnace Bay the area of land cleared by 1840 remained
constant to 1960 (see Section 3). There are no .records of area of land
cleared in 1820, but there are records indicating that agriculture was well
established by 1820. Since there is only one significant decrease in the
oak-ragweed ratio in the core, it is assumed it reflects the time of well-
established agriculture and that the area of land cleared in 1820 was -essen-
tially the same as in 1840. Therefore, an 1820 date has been assigned to
the 94 cm level where the oak-ragweed ratio changes from 1.8 to 0.7.
;• Although chestnut pollen is never entirely eliminated, it deer-eases
rather dramatically at 30 cm. The chestnut blight began to infect trees
by 1910 and by 1930, most of the chestnut trees were dead"-(Anderson 1974)."
In this core, a 1930 date has been assigned to the 30 cm level where the
chestnut decreases. It is believed that the decrease represents the demise
of the species and the reason the pollen persists throughout is probably due
to some mixing of sediments. Fluctuations in total pollen lead to surmising
that mixing may have occurred, but even if this were the case, it is not suf-
ficient to obliterate major changes in the pollen distributions. Based upon
these dated horizons, sedimentation rates average 0.6 on/yr throughout the
core. Assuming a 0.6 cm/yr rate of sedimentation, the influx (numbers of
grains deposited per gram of sediment per year) of the major pollen types
in the core, viz., oak, ragweed, pine, and hemlock, have been plotted.
Furnace Bay Core Number II (Figure 27)—
: This core, 123 cm long, is macroscopically very similar to core FB-I.
The top 84 cm are an homogenized dark grey silt and clay which becomes a
light brownish grey from 84 to 131 cm. Brown bands occur at 23 to 24 cm
and 33 to 34 cm. I
j ' i
I Total pollen does not fluctuate nearly as much as in core FB-I. Total
pollen per gram dry sediment are almost twice as high at the bottom of the
core as at any other level. Total numbers decrease dramatically toward the
center of the core with a zone of no pollen from 56 to 64 cm.
j The oak-ragweed ratio of 18 at the bottom of the core indicates that
'ragweed essentially is absent in this part of the core which extends down to
92 cm. This zone represents presettlement time. At 92 cm, the oak-ragweed
ratio changes to 1.8 and decreases to well below 1 at 84
-------
1978
0.6cm/yr
— 1930
0.7 cm/yr
— 1910
5x10
20.3
IO% 50% 25%
SEDIMENTATION RATE'
£ 0 10 20 30 40 50 60 70 8O 90
en
ui
S
5xl03
CENTIMETERS (x)
OAK
;IO-
I
RAGWEED
Oc>-
5xl03
[
PINE
10'
o
Q.
UJ
O
I
HEMLOCK
1600 1700 1800 I9OO
TIME IN YEARS
20OO
Figure 27. Stratigraphic pollen profile of Core II from Furnace Bay and the
flux of pollen of oak, ragweed, pine and hemlock.
75
-------
LAST
OFTE
-... The chestnut profile fluctuates considerably. The low numbers in the
bottom "of the core (during presettlement time) probably are related to forest
., density. Chestnut flowers in late summer when trees are in full leaf. It is
possible that in dense forests, prior to clearing, much of the chestnut pollen
is filtered out before reaching a depositional basin (see Tauber 1965 for a
discussion of factors affecting the atmospheric dispersion of pollen). After
1820, the numbers of chestnut pollen increase and then decrease in the center
of the core, but this decrease is coincident with very low concentrations of
total pollen. At 44 cm, the numbers of chestnut decrease by one-half; a 1910
date to this horizon has been assigned, which is believed to represent the
initial impact of the blight. At approximately 30 cm, chestnut pollen is no
longer present; a 1930 date has been assigned, the time when the trees were
no longer existent, to this level. Chestnut pollen in the top 4 cm is pro-
duced by the oriental chestnuts which were planted throughout the eastern
United States in the early 1940's.
: Based upon these dates, sedimentation rates average 0.5 cm/yr for the
entire core, with average rates of 0.3 cm/yr from 1790 to 1820, 0.4 cm/yr
from 1820-1910, 0.7 cm/yr from 1910 to 1930, and 0.6 cm/yr from 1930 to the
present. — - - •-•/;" — — —- — — — —- — — --
Because changes in the sedimentation rates in the real world probably
are more gradual than indicated .by the average values, it was decided to
approximate the changes. To do this, it was assumed that the change was
linear and that the rate at the midpoint of the interval was'the average
rate. Accordingly, the midpoints of each interval were plotted against the
sedimentation rate for that interval. These points were connected by lines
the equations of which are. used to obtain the intermediate sedimentation
rates. For core levels below the last dated horizon and above the first
dated horizon, it was assumed that the sedimentation rate from the previous
level remains constant through this section.
; Pollen, seed and diatom influx values (i.e., the numbers of pollen,
seeds, and diatoms deposited per gram or per cm2 of sediment per year)
are calculated by dividing the total counts at each level by the number
of years represented by each sample analyzed. '.
r Based upon the sedimentation rates for core FB-II (Figure 27), the :
pollen influx shows clearly that the major tree species, oak, pine and
hemlock all decrease dramatically with the advent and establishment of
agriculture. The influx of pine and hemlock is particularly interesting
because it does not reflect the presence of abundant pine and hemlock stands
Jin the Appalachian Plateau of Pennsylvania, approximately 100 km northwest
'of Furnace Bay, which were extensive as late as 1840 for pine and 1880 for
hemlock (see Section 3). Although changes in the vegetation of the Piedmont
section of the Susquehanna watershed caused by agriculture are documented in
the pollen assemblages from Furnace Bay cores, changes in the vegetation of
the Appalachian section of the watershed are apparently not reflected because
.they are too distant. The large amounts of pollen of hemlock and pine that
j 'are present in the bottom part of both cores must have originated from trees
Li; ;c growing in the Piedmont which were cut at the time land was cleared for
XT : agriculture...._I.f_the pollen were derived from Appalachian vegetation, it
OUTGi
D!.V,£!\
+MJ*.
PAGE :•:!;•
-------
0? TEX
should be present in sediments deposited after 1820 because the forests in
the Appalachian Plateau were not cleared for agriculture. Apparently pollen
from the upper watershed was not transported into this area during any time
interval. This is in agreement with the observations made on pollen distribu-
tions in the tidal Potomac surface sediments where pollen of trees restricted
to the Appalachian province today are not present in surface sediments approx-
imately 50 km downstream from the source.
Furnace Bay Core Number Ill-
Only oak and ragweed pollen from this core were counted and therefore we
have identified only the agricultural horizon. This occurs at 93 cm based
upon the change in the .oak-ragweed ratio. A date of 1820 was assigned to
this level. Based upon this date, the average sedimentation rate from 1820
to the present is 0.6 cm/yr.
Other Tributaries—
1 Table 14 summarizes all of the dates that have been assigned to dif-
ferent sedimentary horizons in a number of tributaries based upon pollen
analyses. The rates average approximately 0.6 cm/yr from all cores, but
the range within a core is as great or greater than the range between cores •
from the same tributary, or between cores from different tributaries. For
example, in one core from Back River rates range from 0.3 cm/yr to 1.9 cm/yr.
Rates appear higher during the agricultural periods for some tributaries with
large drainage areas (e.g., Back River) than for some with smaller drainage
areas (e.g., Middle River), but the hydrodynamics of the tributaries is also
important. For example, the sedimentation rate in the middle of Back River
is much greater than at the mouth because Back River acts as a depositional
sink (Han 1972).
Conclusions j j
1. The clearing of land for agriculture and the decrease and demise of
chestnut are the two major events that are reflected in pollen assemblages
from estuarine sediments. Dates of 1910 and 1930 are assigned to the chest-
jnut horizons and anywhere from 1790 to 1890 to the agricultural horizon
depending upon the specific location. Rapid urbanization where it has oc-
curred is reflected by increased concentrations of pollen in the sediments.
;In some instances, farm abandonment can be detected by an increase in the
ratio of oak pollen to ragweed pollen.
i ' .' j
j I ;
j 2. Sedimentation rates average approximately 0.6 cm/yr in all of the
cores studied but vary from less than 0.2 cm/yr to approximately 2 cm/yr.
I ! ! . '
I 3. The data gathered so far suggest the influence of land use on rates
of sedimentation is influenced by drainage area and the morphometry of the
•rivers. However, specific relationships will not be studied until sedimen-
tation rates have been obtained for more tributaries.
77
EA-
BOTTOM (
IMAGE A'
OUTSIDE ,
DIMENSION
FOR TABLES
--AND ILLUS-
TRATIONS
-------
TABLE 1.4. SUMMARY OF SEDIMENTATION RATES BASED ON PALYNOLOGICAL INDICATORS THUS FAR OBTAINED FOR CHESAPEAKE BAY AND TRIBUTARIES
Location*
Susquehanna
Flatst
Furnace
Bayt
Furnace
Bayt
Furnace
Bayt
Middle
River
Back
River
Back
River
Back
River
Potomac
River
Potomac
River
Potomac
River
Chesapeake
Bayt
*See Figure
tAnalyses of
Core
3
III
I
II
M-2
T
B
R
1
4
3
4
for
these
Dated Horizons StratigrapMc Indicator for Date
0 cm - 1978 year core was collected
98 cm - 1880 presence of abundant coal particles
0 cm - 1978 year core was collected
93 cm - 1820 large increase 1n ragweed pollen
0 cm - 1978 year core was collected
30 cm - 1930 absence of chestnut pollen
0 cm - 1978 year core was collected
30 cm - 1930 absence of chestnut pollen
44 cm - 1910 decrease in chestnut pollen
84 cm - 1820 large increase in ragweed pollen
92 cm - 1790 moderate increase 1n ragweed pollen
and decrease in tree pollen
0 cm - 1974 year core was collected
4 cm - 1960 Increase in total pollen concentration
34 cm - 1980 large increase in ragweed pollen
0 cm - 1974 year core was collected
38 cm - 1930 absence of chestnut pollen
(12-20 cm deposited In one year)
70 cm - 1910 decrease in chestnut pollen
0 cm - 1974 year core was collected
8 cm - 1960 increase in total pollen concentration
18 cm - 1930 absence of chestnut pollen
50 cm - 1910 decrease in chestnut pollen
88 cm - 1890 large Increase in ragweed pollen
0 cm - 1974 year core was collected
20 cm - 1890 large increase in ragweed pollen
0 cm - 1977 year core was collected
66 cm - 1910 decrease 1n ragweed pollen
0 cm - 1977 year core was collected
24 cm - 1910 decrease in ragweed pollen
74 cm - 1840 large increase in ragweed pollen
0 cm - 1977 year core was collected
30 cm - 1910 decrease 1n ragweed pollen
0 cm - 1978 year core was collected
23 cm - 1820 large Increase in ragweed pollen
locations of cores
cores done under EPA (CBP) Grant Number
Historical Basis for Date
anthracite industry 1n watershed well developed
agriculture well established at ~ 1820
by 1930, all chestnut trees eliminated by blight
by 1930, chestnut trees eliminated by blight
at - 1910, chestnut blight attacked trees
agriculture well established
modest agricultural development
large scale urban development
1890 - time of maximum agriculture in Balto. Co.
chsstnut blight eliminated chestnut trees
pollen concentration greatly reduced but
preservation excellent
beginning of chestnut. blight
large scale urban development
chestnut trees eliminated by blight
beginning of chestnut blight
maximum agriculture in Baltimore County
maximum agriculture in Baltimore County
some farm abandonment
some farm abandonment
agriculture well established
some farm abandonment
agriculture well established in many watersheds
Sedimentation Rate
1 . 0 cm/yr
0.6 cm/yr
0.6 cm/yr
0.6 cm/yr
0.7 cm/yr
0.4 cm/yr
0.3 cm/yr
0.3 cm/yr
0.4 cm/yr
0.8 cm/yr
(0.4 cm/yr)
1 . 7 cm/yr
0.6 cm/yr
0.3 cm/yr
1.6 cm/yr
1.9 cm/yr
0.2 cm/yr
1 . 0 cm/yr
0.4 cm/yr
0.7 cm/yr
0.5 cm/yr
0.15cm/yr
-------
SECTION 6
EUTROPHICATION
INTRODUCTION
Chlorophyll degradation products and diatoms were extracted from all of
the cores studied to be used as stratigraphic indices of eutrophication and
water quality. However, chlorophyll was abandoned because, in many cases, the
results appeared anomalous. It would be difficult to use any interpretations
of water quality based on chlorophyll distributions in a management program.
For example, although the impact of nutrients from sewage effluent is re-
flected clearly by"increases in sedimentary chlorophyll in Back River (Brush '
and Smith 1974), the influence of sewage input in the Upper Potomac River is
not so clearly defined by the stratigraphic chlorophyll profile (Miller and
Brush 1979). The latter situation could be due to poor preservation, or it
could also result from biological recycling of chlorophyll in the water column
by grazers. Dispersion of algal cells away from sources of nutrient also :
could distort the record preserved in the sediments. In any case, sedimentary
chlorophyll was considered unreliable as a consistent indicator of .eutrophica-
tion due to discrepancies in the data. i
< Diatoms, on the other hand, are well preserved in estuarine sediments. ;
They are good indicators of water quality and of eutrophication both in bio- ;
mass and in species composition because many species are sensitive to the \
chemical, physical and biological properties of the environment (Patrick
J975). i i I
'• I
Although diatoms have not been used previously for reconstructing the
history of water quality and eutrophication from sediments deposited in the
estuaries, they have been used quite successfully for studying the effect of
human disturbance on the water quality of lakes (e.g., Stockner and Benson
;1967, Bradbury and Waddington 1973, Bradbury 1975 and Brugam 1978).
METHODS
I A CT I 'MtT
LAC- i l_!i\!_
| A test of similarity was not performed between diatoms in surface sedi-
inent samples and pollen (see Section 5) in order to determine the number of
'samples necessary for representative spatial data. It was assumed that dia-
toms are affected by estuarine transport processes in a manner similar to
pollen, because as particles they fall within the Stokes law of resistance.
jherefore, it is expected that their-depositional behavior is similar to that
of pollen, in which -case only a few samples are necessary to obtain data rep-
resentative of the spatial distributions. _
BOTTOM GF
(WAGE AREA
OUTSIDE
DIMENSION
FOR TABLES
•AND iLLUS-
TRAT;o;-;5
-------
20
40
E 60
u
5,80
Z
UJ
o
80
100
120
10 20 30
0 10 20 30
TOTAL* GENERA
ZONE I
1962
ZONE E
tn _
m
1886
u
ZONE
20 40 60 80 100 120 140
V
1824
ZONE 3C
0 20 40 60 80 100 120 140
TOTAL* SPECIES
<
00
o
100
120
0 10 20 30
TOTAL* GENERA
20 40 60 80 100 120 140
ZONE m
< ro
1880 £ O
ZONE 12
tO U.
20 40 60 8O 100 120 140
TOTAL* SPECIES
Figure 28. Stratigraphic profile of the total number of genera
and species of diatoms in cores from Furnace Bay and
Susquehanna Flats.
80
-------
BEGIN
LAST Li
OF TEX
'!__ The procedures for diatom extraction from sediments and slide preparation
can be found in Appendix A. Each covers!ip was counted in its entirety (ap-
proximately 50 transects) to provide estimates of total diatom concentrations
at each depth. Normally, each coverslip contained between 50 and 150 diatom
frustules. Attempts were made to identify at least 400 frustules at each
depth in order to obtain an accurate picture of the total diatom concentration
and percentages of genera and species present. For lack of sufficient time,
particularly on the longer cores which were sampled more recently, at least "
100 but often not more than 200 frustules were identified for some of the
depths. In this way, a more complete stratigraphic sequence was achieved.
Core I from Furnace Bay (FB-I) was the most extensively analyzed. Dia-
toms were identified and enumerated at TO cm levels with intermediate levels
analyzed between levels of major change in order to identify more precisely
the horizons where changes occurred. We also studied every 10 cm level from
68 cm to the bottom (130 on) from the second Furnace Bay core (FB-II).
5 ' The amount of sand and other coarse material occurs in greater concen-
trations in the Susquehanna Flats cores than in those from Furnace Bay, and
the concentration of seeds and pollen is much "lower." "In Core 2 from ""''
Susquehanna Flats (SF-2), diatoms were identified and counted at 20 cm inter-
vals and in Core 3 (SF-3) at four levels: 79-81 cm, 102-104 cm, 126-128 cm,
and 134-136 cm. This provided sufficient data to identify the major changes
in diatom assemblages and compare these changes with those observed in
Furnace Bay. V ; ;
i The species identifications were based upon Hustedt (1930), Hohn and ;
Hellerman (1963), and Patrick and Reimer (1966, 1975). i
j Data were plotted to show total number of genera and species identified
at different depths in the four cores (Figure 28). Additional data were :
plotted to show absolute and relative abundances of the major genera identi- .
fied (Figures 29 to 32). Graphs were drawn for only those genera comprising ;
at least 10 percent of the total diatoms at one level in one core. The abso-
lute abundance of the diatoms was plotted as diatoms per gram saved sediment
weight. The saved sediment is the material left over after the extraction
process and is similar in grain size to the diatoms. The saved sediment
weight eliminates coal, sand, and other coarse material as well as any or-
ganics that were deposited with the diatoms, thus removing from the vertical
profiles of the diatoms some of the variations resulting from different
sedimentation rates. i
RESULTS , - !
i'l
I Five zones have been identified in Furnace Bay and three zones in
Susquehanna Flats (corresponding to three of the same zones in Furnace Bay).
These zones are distinguished by differences in numbers of genera and species,
absolute abundance of diatoms, dominant genera, and ecological preferences of
species (Table 15). Ecological preferences for the diatoms were obtained from
report for NERC (Lowe 1974) and Patrick and Reimer (1966, 1975).
81
so no?-.
IMAGE
jUTSIL
DlfvicN;
FOR TA
•AND il
TRATiO
-------
ro
TOTAL DIATOMS/ gm
SAVED SED. WT.
0
ACHNANTHES
COCCONEIS
1962
1930
1886
824
40
DIATOMS 110*
gm. SAVED SED. WT.
01 ATOMS/DEPTH
1 W B0
u
o ui
«J 1C IOO
18
£ 120
0 IO
Figure 29. Stratigraphic profiles of total diatoms and total numbers and percent of
total diatoms of Achnanthes, Cocoone-is, Cymbella3 Gomphonema, Navioula and
Nitzschia in cores from Furnace Bay.
-------
TOTAL DIATOMS/gm
SAVED SEO. WT.
COSCINODISCUS
CYCLOTELLA
ZONE I
1962
0 0.9 0 3 10
O 0.5 0 5 IO
0 0.9 0 9 10
~a DIATOMS «10*
0 O.9 O 9 10
1790
ZONEX
EPITHEMIA
1 gm. SAVED SEO. WT.
% DIATOMS/DEPTH
FRAOILARIA
SYNEDRA
9 10
Figure 30. Stratigraphic profile of total diatoms and total numbers and percent of total
diatoms of Cosoinodiscus, Cyolotella3 Eunotia, Epithemia, Fragilaria and
Synedra in cores from Furnace Bay.
-------
TOTAL DIATOMS/gm
SAVED SED. WT
SG!
,. 'li
ACHNANTHES
\
COCCONEIS
ZONE I
6 0 10 20 30 40 SO 0 I 2 0 10 20
I88O
6 0 10 20 SO 40 SO 0 1 2 0 10 20
00
CYMBELLA
GOMPHONEMA
NAVICULA
NITZSCHIA
10 20
0 I 0 10
01 ATOMS « 10"
gm. SAVED SED. WT.
% DIATOMS/OEPTH
0 I 2 1 0 10 20 SO 0 I 0 10
•1880
2 3 0 10 2O 30 OI O 10
Figure 31. Stratigraphic profiles of total diatoms and total numbers and percent of
total diatoms of Achnanthes, Coeconeis, Cymbella, Gomphonema3 Naviaula and
Nitzschia in cores from Susquehanna Flats.
JL.JL.:
-------
O f~ a1
TI > a1
f-'l
y r,i
.
'66'''
en
TOTAL DIATOMS/gm
SAVED SED. WT.
< u.
eo
COSCINOOISCUS
CYCLOTELLA
EUNOTIA
O 9 10 0 I 2 0 9 10 15 20 0
EPITHEMIA
( . .
\
^
1
[•
FRAGILARIA
SYNEDRA
ZONE I
ZONEIE
ZONE HI
1800
ZONE SB.
I DIATOMS « 10°
I gm. SAVED SEO.WT.
I % DIATOMS/DEPTH
Figure 32, Stratigraphic profiles of total diatoms and total numbers and percent of
total diatoms and total numbers and percent of total diatoms of Coscinodiscus,
Cyclotella, Eunotia, Epithemia, Fragilaria and Synedra in cores from
Susquehanna Flats.
-------
Average Average
Number Number
of Genera of Species
ZONE I HIGH
(1962-1978)
FBI 0-12 on
2 samples 28 104
ZONE II HIGH
(1930-1962)
' FBI 12-30 on
1 sample 27 113
ZONE III HIGH
(1885-1930)
fBI 30-57 cm
4 samples 28 100
ZONE IV LOWER
(1790-1885)
fBI 57-93 cm
FBII 68-94 cm 18 42
7 samples
ZONE V HIGH
(7-1790)
FBII 94-128 cm
3 samples 24 86
pre-agriculture
Absolute
Abundance
No. 1 gm
MEDIUM
6 x 106
MEDIUM
8x 106
HEDIUM
6 x 106
LOU
1 x 106
HIGH
24 x 106
FURNACE BAY I
Dominant
Genera
Cyclotella
CoaoinodiaaiB
Synedra
Naoicula
Fragilaria
cfotonenaia
& II
Habitat
plankton periphyte epiphyte
Ispp fspp ffspp
11
18
2
High number of planktonic
forms; low number of
epiphytic forms
3
6
Low number of
forms
G&nphon0nQ
Nitaschia
Cymbella
Sunotia
Saoiaula
Epithenia
Eunotia
Cymbella
Gontphonsnct
Epithania
Achnanthee
3
31
Low number of
forms
3
High
forms
0
42
number of
17
High number of
forms
1
planktonic
6
planktonic
20
epiphytic
8
epiphytic
prefer
organic
environment
6
MEDIUM-HIGH
4
MEDIUM
7
HIGH
3 '
MEDIUM-LOW
3
MEDIUM-LOW
—
SUSQUEHANNA FLATS 2 & 3
MaMtaf
Average Average) Absolute
Number Number • Abundance Dominant
of Genera of Species No. 1 gm Genera
ZONE I HIGH Mi-nniM Cuolotella
SF2 0-48 cm nwivn Coeainodieaue
3 samples , Synedra
24 78 12 x 10° Saaicula
prefer
plankton perlphyte epiphyte organic
fspp #spp jspp environment
14 29 5 7
High number of planktonic HIGH
forms
NO CORRESPONDING BLOOM
ZONE HI HIGH ......... GcmDhoneraa
SF2 S 3 MCDIUM Cy^ella
. 43-98 cm ' ... Aehnanthes
4 samples 22 65 10 x 10° Hauicula
ZONE IV LOWER urnnm Epithemia
JF3 98-134 cm HEDiUH cyabeiia
3 samples , Gamphonema
18 62 14 x 10b
Bottom of
TABLE 15. SUMMARY OF RATIGRAPHIC DATA ON DIATOM
4 28 6 6
Lower number of planktonic MEDIUM-HIGH
forms
\
5 21 83
Higher number of epiphytic MEDIUM-LOW
forms
Core
701 IN CORES FROM FURNACE BAY AND SUSQUEHAHNA FLATS
Bottom of Core
-------
Date lines on the graphs are based upon sedimentation rates derived from
pollen analysis of the cores.
Abundance and Distribution of Fossil Diatom Populations
Core II from Furnace Bay shows a high absolute abundance and a large num-
ber of genera and species of diatoms from the bottom of the core up to about
94 cm. Pollen analysis (see Section 5) shows this depth to be near the agri-
cultural horizon; it is dated approximately 1790. Above 94 cm, abundance and
number of taxa drops dramatically. This trend continued in both cores from
Furnace Bay until approximately 1885 (57 on depth) (Figures 29 and 30). The
reduction in the diatom population at this time can be explained partially by
the higher sedimentation and siltation which in all likelihood occurred with
the clearing of the land during the 19th century. Patrick (1975) states that
homogenization of the habitat by siltation reduces not only substrate diver-
sity but also diversity of light patterns and of current patterns resulting
in a decrease in number of species. Other factors may be involved, such as
possible blooms of blue-green algae which compete with the diatoms for light
and nutrients (Brugam 1978).
In Core FB-I, many new species began invading after 1885 (57 cm depth)
and the number of taxa increased to the same numbers of genera and species as
before. The absolute abundance never recovered.
A large bloom of Fragilaria crotonensis is observed at the 17-19 cm depth
in Core FB-I, but overall diversity remains constant.
Two cores (SF-2 and SF-3) from Susquehanna Flats do not appear to predate
agriculture. For this reason, they do not show any major decrease in abun-
dance and number of taxa such as the one which characterizes the agricultural
horizon in the Furnace Bay cores. The absolute abundance of diatoms in
Susquehanna Flats was found to be relatively the same as post-agricultural
numbers in Furnace Bay.
The cores from Furnace Bay and Susquehanna Flats also show similar pat-
terns of change in the dominant genera (Figures 29 to 30). This indicates
that the regional conditions governing both of these areas are similar. The
patterns reflect trends in the ecology of the Upper Chesapeake Bay and not
local effects within Furnace Bay or Susquehanna Flats.
Both Furnace Bay and Susquehanna Flats showed a dominance of species of
Epithemia in the earliest parts of the cores up until about 1880 (57 cm in
Core FB-I and 98 cm in Core SF-3). Epithemia species showed highest relative
abundance in the preagricultural sediment in Core FB-I. After 1880, species
of Epithemia virtually disappeared from the sediments. The history of the !
area showed that maximum agricultural clearance, maximum coal mining, and j
maximum lumbering occurred on a regional basis between 1870 and 1900. Both ;
factors may be related to the subsequent shifts in diatom assemblages found j
in Furnace Bay and Susquehanna Flats after 1880.
"'- - Between 1880 and 1962 (57-12 cm depth in Core FB-I and 98-48 cm depth in
Cores SF-2 and SF-3), several genera codominate, including Gomphonema,
87
-------
BEGiM j
LAST LINEi
OF TEXT :4
Cymbella, fli-tzechia, Navicula> and Eunotia. Around 1930, a major bloom of
Fragilaria crotonensis occurred in Furnace Bay.
Since 1962 (0-12 cm depth in Core fB-I and 0-48 cm depth in Core SF-2),
there has been a dramatic rise in the number of taxa and absolute abundance
of planktonic species in both core areas of which the three genera Cyclotella,
Coscinodiscus3 and Synedra became dominant. There was al-so a noticeable in-
crease in species of Melosira. and Stephanodiscus.r—The rise in planktonic —
diatoms and subsequent decline in epiphytes may be correlated with the decline
of SAV in recent times (see Section 4).
Cocconeis placentula is a dominant species throughout all four cores at
all depths sampled. It has not been included in Table 15 since it does not
show much change.
Ecology of Fossil Diatom Populations ;
\ Species of diatoms identified from Furnace Bay and Susquehanna Flats have
quite similar ecological preferences. Practically without exception, they are
known to prefer alkaline water of high mineral content and are insensitive to
small amounts of salt. Basically they are indifferent to currents although
many prefer some movement of water. Most of the species are found most often
in lakes and ponds, with a few representatives from river habitats.
Epiphytic species occurred in greater numbers before 1880, and there have
been more planktonic species since 1960. Species of Epithemia were dominant
before 1880; these species are known to be epiphytic on SAV. Their sudden
^decrease after 1880 may be correlated with changes in species and number of i
isubmerged aquatics or with regional factors which possibly affected both. As
mentioned before, their disappearance may be related to the maximum agricul-
tural clearance, mining and lumbering which occurred in this region between
11870 and 1900, and the major floods of 1889 and 1894. Exactly what effects i
these factors might have on Epithemia species is not known. :
i Since around 1880, species which are known to prefer water high in or- :
ganic material and which are favored by nutrient enrichment occur in greater
•abundance, e.g.; Nitzschia fonticola, Nitszchia amphibia, Navicula crypto-
cephala, Navicula rhyncocep'ha.la, Melosira granulata, Cyclotella stelligera,
Stephanodiscus dubius, Fragilaria cTotonensis, and Fragilaria brevistraiata.
Jhis, along with the bloom of Fragilaria crotonensis in Furnace Bay, probably
lis related directly to increased human disturbance of the Upper Chesapeake
;Bay watershed. ; ; i
1 I
Planktonic species were in greatest abundance from 1960 to the present.
Their increase may beadirect response to habitats made available as a result
of the recent disappearance of SAV from the Upper Bay. Cocconeis placentula
is a species found in great abundance at all depths in the cores. C. placen-
tula is a eurytopic species capable of growing on many substrates. C. pla-
centula and Synedra rumpens are the main epiphytes on plants growing today in
the Upper Chesapeake Bay. j
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1... A major exception to the ecological patterns described above are the
species of Eunotia, a dominant genus in Furnace Bay from 1830 to 1920 (80-
50 cm). Species of Eunotia prefer low pH and cannot tolerate any salt. They
often are found in nonsubmerged habitats. Extensive acid drainage occurred
in the Upper Susquehanna watershed from 1860 to 1920 as a result of mining.
A possible explanation for the presence of species of Eunotia in Furnace Bay
cores is that they flourished in the acid conditions of the upper_watershed
and were washed into furnace Bay during periods of high flow.
Species of Adhnanthes occur in much greater abundance and diversity in
Susquehanna Flats than in Furnace Bay. The large amounts of sand and coarse
material found in Susquehanna Flats may provide a possible explanation for
their presence. Achnanthes species are extremely small, usually measuring
between 3 to 15 microns. They prefer to grow on hard or rocKy substrate.
The sand and coarse material in Susquehanna Flats (usually measuring about
1 mm in diameter) would provide a suitable substrate for these small diatoms.
This substrate is not as available in the siltier deposits of Furnace Bay.
Conclusions ~ ; ~ l/l" . ~"~ ~; ~ ~ ~ "
: 1. Most of thediatom species identified are probably growing and living
in the local area. Most of the species show similar ecological preferences
(except Eunotia,spp.) and are normally found in lakes and ponds. Smayda
(1971) has shown that settling rates for diatoms range from 1 to 30 m per
day. The average depth of the water in Susquehanna Flats and Furnace Bay is
1 to 2 m, so diatoms living in these areas would not have time to move out
before settling. Few diatoms would be brought in from other areas, except
possibly in times of flooding when resuspension of sediments and faster cur-
rents are prevalent. :
2. It appears that higher siltation caused by land clearing results in
a decrease in numbers of species of diatoms.
I ' i
3. Cores from Furnace Bay and Susquehanna Flats show a similar diatom
stratigraphy despite the fact that sedimentation processes are quite dif-
ferent in the two areas. This indicates that regional conditions govern the
(ecology of the Upper Chesapeake Bay, and therefore diatom populations are
useful for reconstructing the history of water quality for a regional area.
• i
4. The increase in number of species requiring water high in organic
naterial in both areas since the late 19th century suggests that this change
is related to increased human disturbance of the Upper Chesapeake Bay water-
shed including extensive land clearing and increased sewage input.
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^SECTION 7_
REFERENCES
BEGIN
LAST LINE
OF TEXT ;.,-
Anderson, R. R. 1972. Submerged Vascular Plants of the Chesapeake Bay and
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Anderson, T. W. : 1974. The Chestnut Pollen Decline as a Time Horizon in Lake
: Sediments in Eastern North America. Canadian Journal of Earth Sciences
; ;" "11:678-685. ~ ^ ;" ~ ~~ " " "
Bayley, S., V. D. Stotts, P. F. Springer, and J. Steenis. 1978. Changes in
Submerged Aquatic Macrophyte Populations at the Head of Chesapeake Bay,
1958-1975.. Estuaries 1:73-84.
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Birks, H. H. 1972. Modern Macrofossil Assemblages in Lake Sediments in
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Birks, H. H., M. C. Whiteside, D. M. Stark, and R. C. Bright. 1976. Recent
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Bradbury, J. P. 1975. Diatom Stratigraphy and Human Settlement in Minnesota.
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i
Bradbury, J. P. and J. C. B. Waddington. 1973. The Impact of European
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Plant Ecology. 1973:289-307.
Brugam, R. B. 1978. Human Disturbance and the Historical Development of
Linsley Pond. Ecology 59:19-36.
BOTTOM or
IMAGE AREA;
OUTSIDE ,
DIMENSION
FOR TABLES
AND ILLUS-
i'RAHONS
-------
BEGIN
Brush. G. S. and L. M. Brush, Jr. 1972. Transport of Pollen in a Sediment-
Laden Channel: A Laboratory Study. American Journal of Science 272:
359-381. .
Brush, G. S. and J. Smith. 1974. Stratigraphic Evidence of Eutrophication
in a Subestuary. Chesapeake Research Consortium Publication 43:135-166.
Brush, G. S.,~C. Lenk,~~and J.- Smith. ~In press.—The Natural Forests of
Maryland: An Explanation of the Vegetation Map of Maryland. Ecological
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Commonwealth -of Pennsylvania. 1915. The Publications of the Pennsylvania
• Chestnut Tree Blight Commission, 1911-1913. State Printing Office,
: Harrisburg, Pennsylvania.
County Directors of Maryland. 1956. Cecil County: A Reference Book of
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Craven, A. 0. 1926. Soil Exhaustion as a Factor in the Agricultural History
of Virginia and Maryland, 1606-1860. University of Illinois Press,
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Crowder, A. A. and D. G. Cuddy. 1973. • Pollen in a Small River Basin:
Wilton Creek, Ontario. In: H. J. B. Berks and R. G. West (eds.). /
Quaternary Plant Ecology, The 14th Symposium of the British Ecological
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Davis, M. B. 1973. Pollen Evidence of Changing Land Use Around the Shores
of Lake Washington. Northwest Science 47:133-148.
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Grains in Lakes. Limnology and Oceanography 18:635-646.
j ;
Davis, M. B., L. B. Brubaker, and J. M. Beiswenger. 1971. Pollen Grains in
Lake Sediments: Pollen Percentages in Surface Sediments from Southern
Michigan. Quaternary Research 1:450-467.
i !
Davis, M. B. and J. C. Goodlett. 1960. Comparison.of the Present Vegetation
with Pollen-Spectra in Surface Samples from Brownington Pond, Vermont.
Ecology 41:346-357. j
j
Defebaugh, J. E.: 1907. History of the Lumber Industry. The American
Lumberman, Chicago, Illinois, Vol. 2.
' i
Fenwick, G. H. Unpublished manuscript. Survey of the Submerged Vascular
Vegetation of Eastern Bay and Adjacent Tributaries of the Chesapeake
Bay, Maryland: June-September, 1976.
i • I —
Funkhouser, J. W. and W._R.JEvitt. ..1959. Preparation Techniquesjfor Acid-
>Insoluble Microfossils. Micropaleontology 5:369-375. ";
BOTTOM OF
IMAGE AREA-
OUTSIDE -
DIMENSION
FOR TABLES
'AND iLLUS-
-------
Han, G. 1972. The -Delineation of an Exclusion Area Around the Chestertown
Outfall on the Chester River and the Back River Sewage Treatment Outfall.
Chesapeake Bay Institute Special Report 26.
Hohn, M. H. and J. Hellerman. 1963. Taxonomy and Structure of Diatom
Population from Three Eastern North American Rivers Using Three Sampling
Methods. Transactions of the American Microscopial Society 82:250-329.
Hollander, M. and D. A. Wolfe. 1973. Non-parametric Statistical Methods.
John Wiley and Sons, New York. 115 pp.
Hustedt, F. 1930. Die Susswasser-flora Mitteleuropas. Printed in Germany.
466 pp.
James, H. F. 1928. The Agricultural Industry of Southeastern Pennsylvania:
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Pennsylvania, Philadelphia, Pennsylvania.
Johnson, G. F. 1929. Agriculture in Pennsylvania: A Study of Trends,
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General Bulletin, No. 484. Harrisburg, Pennsylvania. 94 pp.
Johnston, G. W. 1881. History of Cecil County, Maryland, and the Early
Settlements Around the Head of Chesapeake Bay and on the Delaware River.
Reprinted by the Baltimore Regional Publishing Company, Baltimore,
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Latrobe, B. H. 1817. The Susquehanna River Survey Map. Commissioned by the
State of Pennsylvania, Harrisburg, Pennsylvania.
Lemon, J. T. 1972. The Best Poor Man's Country: A Geographical Study of
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Lintner, S. F. Unpublished manuscript. The Susquehanna River Survey Map.
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Martin, A. C. and F. M. Uhler. 1939. Food of Game Ducks in the United
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McNown, J., J. Malaika, and H. R. Pramanik. 1951. Particle Shape and Set- '
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92
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Miller, A. E. 1949. Cecil County, Maryland: A Study in Local History. C
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/
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BEGIN
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APPENDIX
MODIFICATION OF METHODS IN QUALITY ASSURANCE REPORT
Diatom Extraction Procedure
Materials: 50 mi beakers
80-95% H202 (hydrogen peroxide)
25% HCS,
HNOs (concentrated)
K2Cr207
95% EtOH
600 ma beakers
Method:
1. Weigh beakers (50 mJl beakers).
2. Place one (1) mi sediment sample in beaker and reweigh.
3. Place in drying oven overnight and reweigh.
4. Add 25 mi H202 and place watch glass over beaker.
a. Let stand for one hour to overnight; swirling occasionally to reduce
foam.
b. Warm over low heat (@80 C); be careful not to let it foam over; con-
tinue heating until the reaction begins to boil exothermically and
produce "white smoke."
c. Remove from heat. When reaction is complete, add distilled H20 and
let stand overnight.
(This step disperses the sample and oxidizes some organics.)
5. Carefully decant. j
6. Add 25 mi 25% HCfc, and heat for 30 minutes. Remove from heat and add dis-
tilled water. Let stand for 24 hours. ;
(This step removes carbonates and small fragments.) j
7. Carefully decant. :
96
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8. Add 25 ml concentrated HN03 and a pinch of K2Cr207. Boil for two hours.
Remove from heat, add H20 and let stand for 24 hours.
(This step oxidizes organics.)
: 9. Carefully decant.
10. Add distilled H20 and let stand for 24 hours "(Wash #1).
11. Carefully decant. ;
12. Wash #2. .;•
13. Carefully decant.
14. Wash #3. ; ' I
15. Carefully decant. ;
16.- SQUIRT in distilled H20 to the 40 mi mark and wait 30 seconds. Pour — -:
; supernatant into 600 ma beaker. Repeat this 9 more times. (This step
: is used to remove the coarse fraction of the sample.)
a. After the 10 decantation, place the beaker and residue in the drying
oven. - After 24 hours weigh beaker and residue. Clean the beaker and
reweigh. ! ;
b. Let the beaker with supernatant stand for 24 hours. ;
17. Pour off supernatant carefully. \ \
18. Transfer residue to clean 50 m£ beaker (pre-weighed). Use 95% EtOH. Put
in drying oven. . j
19. Allow to sit at room temperature and then weigh. ;
20. Add 10 ml distilled water and stir with soft tip to disperse. i
I \ !
21. Transfer sample to storage bottle (premarked at 50 mi volume). (Use :
distilled H20 to store diatoms.) | I
Methods described above are a modification by James Stasz of Funkhouser, John i
W. and William R. Evitt (1959). Preparation Techniques for Acid-Insoluble j
Microfossils, Micropaleontology, Vol. 5, No. 3, pp. 369-375. j
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Diatom Slide Preparation
Materials: Corning plain micro slides 3 x 1"
Corning cover glass No. 1 22 mm2
1 m£ tuberculin syringes
1 m£ graduated glass pipets
Wanning plate and hot plate
Hyrax mounting medium
Method:
The diatoms are diluted in distilled water to desired concentration (dif-
ferent for every sample), and then 0.06 mi of this solution are measured onto
a cover slip using a graduated glass pipet attached to a tuberculin syringe.
The cover slips are heated over a warming plate until the water drop dries
(about 15 minutes). One drop of Hyrax is added to each cover slip and two
coverslips are permanently mounted to one slide.
98
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA 600/8-80-040
2.
SAV 3
3. RECIPIENT'S ACCESSION NO.
4. TIJLE AND SUBTITLE
BIOSTRATIGRAPHY OF CHESAPEAKE BAY AND ITS
TRIBUTARIES - A Feasibility Study
5. REPORT DATE
Date of Approval
April. 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Grace S. Brush, Frank W. Davis, Sherri Rumer
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Geography and Environmental Engineering
The Johns Hopkins University
Baltimore, Maryland 21218
10. PROGRAM ELEMENT NO.
2BA711
11. CONTRACT/GRANT NO.
Grant 0R805962
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Chesapeake Bay Program
2083 West Street, Suite 5-G
Annapolis, Maryland 21401
13. TYPE OF REPORT AND PERIOD COVERED
Final 7-1-78 to 10-31-79
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Seeds of submerged aquatic vegetation (SAV), diatoms and pollen of terrestrial
plants extracted from sedimentary cores 1 to 1.5 m long, in estuarine tributaries,
yield information regarding changes in SAV populations, eutrophication and
sedimentation rates since European settlement. Cores taken from undisturbed
depositional areas represent regional conditions with respect to eutrophication and
sedimentation, because diatoms and pollen are affected by estuarine transport pro-
cesses in such a manner that local patchiness is erased but regional differences
are not obliterated. Vertical (historical) changes in diatom and pollen
distributions therefore can be described for a whole region with only a few cores
because the data from 1 sample at the locale is representative of the whole
locale.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Agriculture, Biostrati-
graphy, Chesapeake Bay,
core, diatom, estuary,
eutrophication, pollen,
sedimentation, seed,
settlement, SAV, tributa
-y
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