-------
SUBMERGED AQUATIC VEGETATION PROGRAM AREAS
Srbmergod Aquatic Vegetation (SAV) occupies an important position in
the ecology of the Chesapeake Bay system, SAV provides food, shelter,
habitat and breeding ?.r':».
vtth thi overall ecological health of the Bay and may be an indicator of
significant environmental daroaga to the Bay system.
A aaripgament plan for SAV must await a clear definition of the cause~and-
effect relationships that bear upon the problem. To this end, the Chesapeake
Bay Program is addressing the. impact of water quality factors upon SAV and
those lining resources known or suspected to be dependent upon SAV, Study
oroducf::? will identify, and where possible quantify, important ecosystem
f'^cf.ioris th»t EA~"* perform." ir» the P^y system. These results will provide
^.b<2 knowledge base from which water quality taa-agsment alternatives will be
rjev?.!.r>p~:d for the enhancement of SAV and associated living resources.
SAV 1.1
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BIOSTRATIGRAPHY OF THE CHESAPEAKE BAY: A FEASIBILITY STUDY
PRINCIPAL INVESTIGATOR(s); PROJECT NUMBER:
Grace S. Brush R805962
PERFORMING ORGANIZATION: EPA PROJECT OFFICER;
Department of Geography & Thomas Nugent
Environmental Engineering
The Johns Hopkins University
34th and Charles Streets
Baltimore, MD 21218
BUDGET: PROJECT PERIOD:
EPA Share $134,675 Begin - 07/01/78
Performing Organization End - 10/31/79
Share 7,088
TOTAL $141,763
OBJECTIVES:
The project investigates the feasibility of obtaining scientific infor-
mation for Chesapeake Bay management from stratigraphic analysis of sediments,
Changes in SAV populations, eutrophication, and sedimentation rates are
defined over past time periods of a few hundred years or more and correlated
with natural events and human activity.
SCIENTIFIC APPROACH:
Core samples of Bay sediments, 5 centimeters in diameter and up to
2 meters in length, are collected from undisturbed locations in three parts
of the Bay; Susquehanna flats and Furnace Bay in the Upper Bay, Eastern Bay
in the mid-Bay region, and Hungar's Creek on the Eastern Shore at the Lower
Bay. The cores are examined to determine the most appropriate fossil indica-
tors- of SAV and eutrophication. Cores are split for analyses which will
provide for extraction of SAV fossils, and for analyses for total organic
carbon, sedimentary chlorophyll, pollen and diatoms. Cores taken from the
Bay proper are split and analyzed by pollen and Pb2io to compare the dating
methods. Historical and meteorological dates are compiled for correlation
with data obtained from the core analyses. The present study is considered
to be a feasibility study for a more detailed program, grant number R806680 .
The effort also includes the design of a statistically reliable
sampling procedure for further work.
PRODUCTS;
Results of the project include vertical profile descriptions of SAV
populations, biomass and sedimentation rates for the period- of time covered
by the extracted cores. There will be a report describing methodologies and
correlating the data on long-term changes in SAV, eutrophication and sedimen-
tation rates to natural events (such as hurricanes) and to man's impact on
the Bay during these periods.
SAV 2.1
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BIOSTRATIGRAPHY OF THE CHESAPEAKE BAY AND ITS TRIBUTARIES
PRINCIPAL INVESTIGATOR(s); PROJECT NUMBER;
Grace S. Brush R806680
PERFORMING ORGANIZATION: EPA PROJECT OFFICER:
Department of Geography & Thomas Nugent
Environmental Engineering
The Johns Hopkins University
34th and Charles Streets
Baltimore, MD 21218
BUDGET: PROJECT PERIOD:
EPA Share $ 99,285 Begin - 11/01/79
Performing Organization End - 08/31/81
Share 5,225
TOTAL $104,510
OBJECTIVES:
This project expands the work done by the feasibility study conducted
under grant number R805962)*. The project will study the natural
cycles of SAV and diatom populations over several hundred years, and correlate
deviations from these cycles resulting from human impacts or natural events.
Sedimentation rates will be studied and relationships to the natural events
and land use changes will be established.
SCIENTIFIC APPROACH:
Core samples of Bay sediments, 5 centimeters in diameter and up to
2 meters in length, collected from undisturbed locations in four areas of the
Bay are to be examined for fossil indicators of SAV and eutrophication. The
cores are split for analysis of SAV fossils, total organic carbon, pollen and
diatoms. Historical and meteorological data are to be compiled for correlation
with'core data. Bay sediment samples will be collected from the Patuxent and
Choptank subestuaries in the Upper Bay, and the York and Ware subestuaries in
the Lower Bay. Additional long cores (~12 m) will be analyzed from two
locations - one in the Upper Bay and one in the Lower Bay - to compare
changes in pre- and postsettlement core sections.
PRODUCTS:
There will be a report describing methodologies and relating the data
on long-term changes in SAV, eutrophication and sedimentation rates to
natural events and to man's impact on the Bay during these periods. Data
will be computerized showing vertical profile descriptions-of SAV populations,
eutrophication and sedimentation rates for the time periods" covered by the
extracted cores.
SAV 2.2
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BIOSTRATIGRAPHY OF CHESAPEAKE BAY
AND ITS TRIBUTARIES
A Feasibility Study
(Final Report)
ABRIDGED
by
Grace S. Brush, Frank W. Davis, and Sherri Rumer
Department of Geography and Environmental Engineering
The Johns Hopkins University
Baltimore, Maryland 21218
R 805962
Thomas Nugent
Environmental Protection Agency
Chesapeake Bay Program
6th and Walnut Streets
Philadelphia, Pennsylvania 19106
SAV 2.3
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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 popula-
tions, eutrophication and sedimentation since European settlement.
Cores taken from undisturbed depositional areas represent regional
conditions with -respect to eutrophication and sedimentation, because dia-
toms and pollen are affected by estuarine transport processes in such a
manner that local patchiness is erased but regional differences are not
obliterated. Vertical (historical) changes in diatom and pollen distri-
butions therefore can be described for a whole region with only a few
cores because the data from 1 sample at a locale is representative of the
whole locale.
SAV seeds, hoic-ever, are not transported as far because they are
laiger and have a low buoyancy. Hence their spatial distributions are
•highly variable representing local rather than regional populations.
This requires that, in reconstructing the history of SAV, a few locales
where environmental changes are well documented be studied in detail,
thus allowing generalizations about the effect on SAV populations of
changes in turbidity and water chemistry.
SAV seeds extracted from cores in the Upper Bay, even though highly
variable, reflect consistently the demise of SAV after the 1972 Hurricane
Agnes, and show major changes in populations of some species since Euro-
pean settlement.
SAV 2.4
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Pollen of terrestrial plants extracted from 12 cores in 5 tribu-
taries and 1 from the Bay proper indicate that sedimentation rates vary
from approximately .2 cm/yr to approximately 2 cm/yr between cores in
different areas and vary within a core from .3 cm/yr to 1.9 cm/yr indi-
cating a high degree of variability in sedimentation rates both spatially
and temporally. This variability appears to be related to land use, but
is influenced also by the size of the drainage area and the morphometry
of the tributary.
Diatoms extracted from cores in the Upper Chesapeake Bay show a de-
crease in the total number of taxa, the number of epiphytic species, and
in abundance with the onset of agriculture. The number of species pre-
ferring organically enriched water increased from the 1820's to the
present, reflecting the influence of increased human occupation of the
watershed on the aquatic environment.
Key words: agriculture, biostratigraphy, Chesapeake Bay, core* diatom,
estuary, eu-^rophication, pollen, sedimentation, seed, settlement, sub-
merged aquatic vegetation, tributary.
SAV 2.5
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SECTION 1
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
t
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 a comparison of present
land use and existing biological and chemical conditions of the estuary
with conditions of land use and concurrent biological and chemical condi-
tions of the system prior to human disturbance and when influences other
than current usage were dominant.
There are very few historical data, unfortunately, that can be used
for such comparative studies. Even where biological and chemical para-
meters have-been monitored, standard procedures have not been used in all
cases, coverage has been limited to a few specific problem areas and in
very few instances 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 drainage of the watershed and the morphometry of the tributary
are specific to the tributary and its watershed. Very few tributaries
are sufficiently similar so that interpretations based on data collected
from one can be applied to others, much less to the main stem of the Bay.
Nevertheless, a compilation of changes or trends in watershed use
SAV 2.6
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and the biology and chemistry of tributaries over long time intervals
would provide an overall view of the effects of watershed use on the es-
tuarine system, and would indicate whether present conditions are unique,
a repetition of recurrent conditions or are continuous with the past.
Although historical records are not adequate for such an evaluation,
the stratigraphic method 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
compare conditions in the aquatic environment before and after human occu-
pation of the watershed.
The stratigraphic method should be feasible for compiling long his-
torical records of'the Chesapeake Bay because the Bay and its tributaries
are depositional basins in which are entrapped and preserved some aquatic
organisms (e.g., diatoms, cladocerans), parts of organisms (e.g., sponge
spicules, pollen and seeds of terrestrial and aquatic plants) and meta-
bolic products of organisms (e.g., chlorophyll degradation products,
amino acids). These fossil organisms and remains of organisms represent
a portion of the estuarine 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 changes
in the presence or absence and in the species composition of submerged
aquatics preserved at different stratigraphic horizons represent changes
in submerged aquatic vegetation at the time of deposition. Similarly,
changes in concentrations of chlorophyll products where preserved can
yield estimates of biomass or productivity and hence are potential indicators
SAV 2.7
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of eutrophic conditions. Changes in species composition and quantity of
algae that lend themselves to preservation also provide quantitative
data on eutrophication and water quality, because many of those species
are sensitive to changes in water chemistry. Changes in terrestrial
pollen composition are an indicator of watershed land use, e.g., a change
from high percentages of oak to high percentages of ragweed pollen indi-
*
cates that the land has been cleared of forests. In many watersheds this
results in increased runoff. Such changes in terrestrial pollen composi-
tion can be dated from historical records. Sedimentation rates can then
be calculated from dated sedimentary horizons to provide a measure of
turbidity and siltation at different times. Rates of sedimentation are
necessary also for"calculating the quantity of organisms deposited per
unit time.
In addition to providing sedimentation, rates, pollen of terrestrial
plants can be used to measure the distance some sediment is transported
in estuaries_. Pollen, as a particle, falls within the range of Stokes
law of resistance and can be expected to behave in water like particles
with small Reynolds numbers, such as fine-grained sand and silt. Where
the vegetation adjacent to the river differs fundamentally in generic
composition with distance downstream, the pollen produced by these dif-
ferent genera can be considered labeled particles, because they are dis-
tinguishable. Direct measurements can be made of the distance these pollen
grains are moved in the tributary from their source, by observing their
distributions in the surface sediments. One can infer that particles
similar hydrodynamically will be transported approximately the same distance.
SAV 2.8
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The path, distance and rate of sediment transport and deposition
provide necessary information for estimating the rate of transport and
ultimate fate of toxic and other substances that associate with fine-
grained sediments in the aquatic environment.
The stratigraphic method has met with reasonable success in describ-
ing the effects of land use and human disturbance on lakes (e.g., Davis,
1973, Birks et al., 1976; Brugam, 1977). The results however are compli-
cated due to variations imposed by differential sedimentation (Davis, 1973;
Davis and Brubaker, 1973). Similar studies have not been carried out for
reconstructing the history of estuarine systems even though estuaries too
are depositional basins. However, estuaries differ from lakes because the
sediment is transported fluvially and stratigraphic interpretations must
take into account the dynamics of estuarine transport.
This study was undertaken to investigate the feasibility of the strati-
graphic method for describing changes in submerged aquatic vegetation,
eutrophicatiun and sedimentation rates in the Chesapeake Bay estuary over
long periods of time.
SAV 2.9
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SECTION 2
OBJECTIVES
The objectives of the study were:
(1) to identify the organisms and parts or products of organisms that are
the best fossil indicators of submerged aquatic vegetation and eutrophi-
cation by observing which fossils are present most consistently from
cores taken in several tributaries, and to identify the changes in pollen
populations that would serve to date stratigraphic horizons;
(2) to determine the number of cores necessary for obtaining representa-
tive data 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 preferable depositional zones
for different fossils; and
(4) to defin~e che resolution of the information with regard to the spatial
area represented by a core (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 I.
SAV 2.10
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SECTION 3
STUDY AREA
Cores were extracted from Eastern Bay, Hungar's Creek, Susquehanna
Flats and Furnace Bay (Fig. 1 ). We decided 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,
we chose the Susquehanna Flats-Furnace Bay area in the Upper Chesapeake Bay
because depositionally it comprises two entirely different zones, one an
undisturbed depositional basin and the other a zone characterized by scour-
ing and redeposition. We sought to determine whether the history of
changes in submerged aquatic vegetation, eutrophication, and sedimentation
in the Susquehanna Flats and the Upper Chesapeake Bay where the depositional
history is complicated by scouring and redeposition would be reflected accu-
rately in a small embayment such as Furnace Bay, where the sediments once
deposited remain essentially undisturbed.
Description
The Susquehanna Flats is a broad shallow estuary of roughly 90 km ,
located at the juncture of the Susquehanna River and Chesapeake Bay (Fig.
2 )•
The average depth of water at mean low tide is 1.2m. The Flats are
influenced very little by the tide and receive a large freshwater flow
from the Susquehanna River. Consequently, the water is essentially fresh
except during very dry periods. High flows from the Susquehanna River
SAV 2.11
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during storms result in periodic scouring and redcposition of sediments.
Since the Flats are dominated very much by the Susquehanna River, their
history should reflect the history of the effects of events in the Sus-
quehanna watershed or at least some part of it on the water of the Upper
Bay.
Furnace Bay is a small embayment on the northern edge of the Susque-
hanna Flats and is fed by Principco Creek, (Fig. 3 ). Unlike the Sus-
quehanna Flats, it is an excellent depositional basin with a substrate
consisting entirely of silt and clay. It experiences minimal scouring
and redeposition. The eastern side of Furnace Bay's watershed is forested
to a larger extent than the western side which is cleared mostly for agri-
culture (Fig. 3 ) .' The water is uniformly shallow, never deeper than 2
meters. Furnace Bay may be somewhat more enriched than Susquehanna Flats
because of local sewage discharge into Mill Creek and subsequently into
Furnace Bay.
History
In this section, we present synopses of trends and events in the Sus-
quehanna River Basin and Furnace Bay watershed which relate directly to
the stratigraphic records from Susquehanna Flats and Furnace Bay. Sources
of information are separated from the general bibliography for the report
and are listed at the end of this section.
SAV 2.12
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CONCLUSIONS AND DISCUSSION
The record left by organisms and parts of organisms in estuarine
sediments is sufficiently complete to provide adequate data for recon-
structing some of the chemical, physical and biological conditions of the
estuary over long time intervals. The fossils used as indicators of these
parameters must be chosen carefully in terms of their ability to preserve,
their sensitivity to environmental change and our knowledge of their ecol-
ogy. Once a particular indicator is chosen, sampling design must take
into account the variability characteristic of the population it represents
and the effects of estuarine transport processes on its final distribution
in the sediments. Core locations must be selected also from areas of un-
disturbed deposition 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 es-
tablish sampling designs to describe regional trerds or changes over long
time periods in submerged aquatic vegetation, eutrophication and sedimen-
tation rates. In order to accomplish this objective we used the Upper
Chesapeake Bay as a study area because it has a diverse depositional
environment, thereby allowing us to compare the biostratigraphy of dif-
ferent depositional basins in the same area.
The best fossil representatives of SAV are seeds and diatoms are a
useful indicator of chemical and eutrophic conditions. Pollen of terres-
trial plants are used to date stratigraphic horizons in order to obtain
SAV 2.13
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sedimentation rates and to calculate seed and diatom flux. The sediments
also contain fossil indicators of other populations, e.g., species of
sponges and carapaces of cladocerans. These populations can provide in-
formation with regard to salinity and the biology of the water. A more
detailed and complete history can be compiled by studying fossils of a
greater number of different populations. However, since the analysis of
a sedimentary core is time-consuming, careful consideration should be
given to the kind of information being sought and to our knowledge of the
ecology of the organisms represented by the fossils. If nothing is known
of the existing distributions and ecological requirements of a particular
organism, it will be difficult to interpret fossil distributions in terms
of their response to environmental change until their present day distri-
butions, requirements and limitations are understood.
Sedimentary layers dated thus far by pollen analyses indicate that
the sedimentation rates vary from .15 cm/yr to approximately 2 cm/yr. A
comparison Gf pollen distributions in surface sediments with distributions
of trees in a wide band adjacent to an estuary sampled for pollen suggest
that estuarine processes disperse the pollen in the estuary to a greater
or lesser extent depending on the settling velocities of the individual
pollen grains. Estuarine dispersion serves to erase some of the local
variation due to patchiness of tree distributions, uneveness of pollen
production, etc. that were not eliminated by atmospheric dispersion, but
it does not mask regional distributions of vegetation. Since pollen be-
haves in water similarly to particles with small Reynolds numbers such
as silt and clay, our results suggest that fine-grained sediments are
SAV 2.14
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transported similarly within the estuary. That is, sediments are not likely
to move very far from their source, except when and where conditions are ex-
tremely turbulent, such as during intense storms and at the mouths of the
tributaries. Consequently, in most cases, we can expect sedimentation rates
to be governed by drainage area and local land use. Our data, though pre-
liminary, substantiates this expectation. The large degree of variation in
sedimentation rates between cores suggest 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 tribu-
taries draining small areas; in the latter, there is little fluctuation in
rates.
The above observations are preliminary in that they are based on data
from a total of 12 cores from 5 tributaries and 1 core from the Bay proper.
It is necessary to measure the rates in most of the major tributaries in
order to delineate as precisely as possible the importance of all factors
involved in the transport and deposition of sediment in the estuary.
The similarity in vertical diatom assemblages between cores taken in
Susquehanna Flats and Furnace Bay indicates that water quality is governed
by regional conditions in the watershed. The settling velocities of dia-
toms are such that it is unlikely the populations of the 2 areas are mixed.
More likely, they represent in situ populations which may have been trans-
ported short distances within each area. Susquehanna Flats and Furnace
Bay are quite different from each "other hyclrologically. However, water
chemistry in both areas is probably influenced more by the character and
SAV 2.15
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use of the watershed and therefore may be similar in both places. The dia-
toms, which are sensitive to water chemistry, appear to be responding pre-
dominantly to a more regional pattern of water quality. Thus, we can
expect to obtain historical data representative of the effect of watershed
use on regional water quality by studying vertical diatom distributions in
1 of 2 cores from a good depositional area.
The dissimilarity between vertical profiles of SAV seeds in cores from
Susquehanna Flats and Furnace Bay as well as the variability between cores
within each area recognizes the high degree of patchiness characteristic of
SAV. SA'v 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
patchiness. In contrast to diatoms and pollen, the variability that charac-
terizes SAV and the ineffectiveness of transport processes to erase this
local variability requires that a few strategic locations, where specific
impacts 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.
SAV 2.16
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NOTES
-------
DISTRIBUTION OF SUBMERSED AQUATIC VEGETATION
IN CHESAPEAKE BAY, MARYLAND - 1979
PRINCIPAL INVESTIGATOR(S); PROJECT NUMBER;
Robert J. Macomber X-003202-01
PERFORMING ORGANIZATION: EPA PROJECT OFFICER:
Chesapeake Bay Foundation Thomas Nugent
"The Church"
Prince George & East Streets
Box 1704
Annapolis, MD 21404
BUDGET: PROJECT PERIOD;
EPA Share $56,430* Begin - 6/15/79
Performing Organization End - 4/15/81
Share 2,970
TOTAL $59,400
OBJECTIVES!
This study largely continues the activities of grant number R805977.
The two project objectives are: (1) to establish a 1979 inventory
ot SAV distribution and species concentration in Maryland waters, and (2) to
compare 1979 with 1978 SAV inventory for identification of gross change in
SAV distribution and abundance. The companion study to this project is grant
number X-003201-01) .
SCIENTIFIC APPROACH:
Aerial reconnaissance will be conducted to identify areas that are
significantly vegetated. Photographs will be taken of significantly vegetated
areas at a scale of 1:24,000. SAV distribution and abundance maps will be
developed for areas showing significant change from the 1978 inventory.
Quality control will be assured by consideration of the following factors:
(1) SAV growing season, (2) turbidity, (3) atmospheric haze, (4) wind conditions,
(5) sun angle, and (6) tide. Field samples will be collected to provide
ground verification of the photointerpretation process. The results of this
inventory and subsequent comparison with the 1978 study will assist in
designing the 1980 distribution and abundance project.
PRODUCTS:
Project results will include: (1) a current inventory of SAV in Maryland
waters in the form of maps with species annotation, of areas showing significant
distribution changes of SAV since 1978, and (2) an estimate of trends in SAV
populations from 1978 to 1979.
Represents Ist-year funding of a 2-year program.
SAV 3.1
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1979 DISTRIBUTION OF SUBMERSED AQUATIC VEGETATION
IN CHESAPEAKE BAY, MARYLAND
Principal Investigator:
Robert T. Macomber
Earth Satellite Corporation
Washington, D.C.
1.0 CURRENT WORK STATUS AND PROGRESS TO DATE
Work began on this investigation on July 12, 1979, with a preliminary
reconnaissance via seaplane of the Maryland waters of the Chesapeake
Bay, to determine/confirm what areas were "significantly vegetated" in
1979. The 1978 SAV distribution maps were used as a basis for compari-
son. Quad sheets that were significantly vegetated in both 1978 and
1979, and quads that showed obvious SAV distribution changes were in-
cluded for further study this year. Thirty-five (35) quads fell into
this category. Thirty (30) of the quads listed below will be selected
as per the budget (to be photographed and ground truthed).
Ground truth via the seaplane commenced on August 20, starting with
the western shore quads and proceeding south and to the Eastern Shore.
Approximately half of the quads were ground truthed as of September 4,
1979.
No aerial photography has been obtained due to persistently poor
weather conditions since the start date, and high turbidity levels
caused by Hurricane David. Flight!ines have been laid out to effi-
ciently cover the SAV area and will be flown in mid-September and early
October, as soon as suitable flying weather and low tidal windows
coincide with low water turbidity.
SAV 3.2
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2.0 PROBLEMS AND DIFFICULTIES ENCOUNTERED, AND REMEDIAL ACTIONS TAKEN
No unsolvable difficulties have been encountered, yet. A late
start date has placed some stress on the field crew to remain on sche-
dule. Additional delays have been caused by stagnant weather systems in
the Bay area through July and August. Low ceilings and visibility, and
southwesterly winds causing high turbidity, have slowed the ground truth
effort and prevented aerial photography. In order to maintain the
ground truth schedule, seaplane overflights are being conducted at a
slightly higher than normal air speed to maximize the shoreline covered
between the 11:00 a.m. to 6:30 p.m. VFR weather periods of the day.
Landings and subsurface samples of SAV are still required and are being
conducted, but at a slightly reduced frequency and with a shorter sur-
face residence time. More planning, selection, and mental notation of
the landing sites prior to descent and spot landing have reduced the
surface truth time by 25%. The field team, with more than two years
experience in viewing grasses from the air, is making greater use of
binoculars to reduce the landing frequency without affecting the accu-
racy of the survey.
In order to maximize efficiency of the aerial photo procurement,
the SAV areas were grouped and flight!ines were laid out in the most
efficient orientation to maximize coverage with a minimum number of
photographs and flightline miles.
Some difficulties have been encountered in obtaining clearance to
enter the Aberdeen and Patuxent restricted areas for ground truth and
aerial photography. A new FAA directive and a new chapter in the Air
SAV 3.3
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Traffic Controllers Handbook may ease the problems encountered by the
photo pilot in gaining entry to restricted air space when the fleeting
coincidence of proper photo conditions occurs.
3.0 PRELIMINARY DATA RESULTS
During seaplane reconnaissance for ground truth of SAV distribution,
the field team has encountered areas with increases in SAV areal extent
up to 50% (on the Chester, Magothy and Severn Rivers) and decreases of
only 10%. Thus, 1979 distribution may show a significant net increase
in SAV area over 1978. It is not possible to distinguish between short
term annual perturbations in SAV area and long term trends at this time.
A third point of reference, the 1980 distribution, may indicate the
presence (or absence) of a trend.
4.0 IDENTIFIABLE PRODUCTS TO-DATE
No final products are available.
5.0 ANTICIPATED ACTIVITIES FOR THE NEXT SIX MONTHS
By the end of October, 1979, the field reconnaissance and aerial
photo data will have to be complete as substantial diebacks will begin
to occur. Photointerpretation will begin in November and is scheduled
for completion by the end of March, 1980. Photo comparisons of the
amount of change in distribution in 1979 relative to 1978 will be made
for the 30 quads photographed and up to 20 new maps can be made within
the budget.
SAV 3.4
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6.0 SUGGESTED MODIFICATIONS
Digitizing SAV bed delineations, area tabulations and comparison
with the 1978 areal extent by quad sheet and by watershed would provide
a more readily understood result than map products alone. Bay area
managers would be able to assess the short term trends on a baywide
basis and on a local basis more readily.
7.0 RECOMMENDED FUTURE RESEARCH
An early grant approval for the 1980 distribution and monitoring
survey would greatly increase the comprehensiveness of the study. This
year, a late start date and budget restrictions precluded early season
distribution mapping. Zanichellia palustris bed locations and early
season distribution for all other species was not mapped. Significant
distribution changes occur throughout the growing season that should be
documented. In 1980, an early start, i.e., May, and an early and late
season photo coverage is budgeted which will greatly increase the accuracy
of the end product.
SAV 3.5
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SELECTION LIST OF
1979 QUADS TO BE PHOTOGRAPHED AND GROUND TRUTHED
1
8
9
13
15
16
17
18
19
20
21
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SAV 3.6
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DISTRIBUTION OF SUBMERGED VASCULAR PLANTS IN THE
CHESAPEAKE BAY, MARYLAND - 1978
PRINCIPAL INVESTIGATOR(S); PROJECT NUMBER;
Richard R. Anderson R805977
PERFORMING ORGANIZATION: EPA PROJECT OFFICER;
Department of Biology William Cook
The American University
Washington, D.C. 20016
BUDGET: PROJECT PERIOD:
EPA Share $137,397 Begin - 6/01/78
Performing Organization End - 1/31/80
Share 9,022
TOTAL $146,419
OBJECTIVES:
This study, a companion project of grant number R805951, seeks
to (1) establish an inventory of SAV distribution and species concentration
in Maryland waters, and (2) assess the usefulness of archival aerial photog-
raphy for estimating trends in distribution and abundance in the Bay.
SCIENTIFIC APPROACH:
Aerial photography and photointerpretation are utilized to establish a
data baseline. Photographs of the submerged aquatic vegetation are taken to
match the United States Geological Survey's quad sheet scale of 1:24,000
and quality control is assured by consideration of the following factors:
(1) SAV growing season, (2) turbidity, (3) atmospheric haze, (4) wind condi-
tions, (5) sun angle, and (6) tide stage. Field samples are collected to
provide ground truth verification of the photointerpretation process.
PRODUCTS:
Study products include: (1) a current inventory of SAV in Maryland
waters in the form of maps showing distribution of SAV with species annotation,
and (2) an assessment of trends in SAV populations in selected areas where
usable historic photography is available.
SAV 4.1
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Distribution of Submerged Vascular Plants, Chesapeake
Bay Maryland.
Richard R. Anderson, P. I.
The American University
Project Status Report
Sept. 15, 1979
Current Work Status.
All work has been completed on this project. Remaining effort
involves final report preparation.
Progress to Date
Maps have been produced showing SAV distrivution on 77
U.S.G.S. quad sheets of the Maryland portion of the Chesapeake
Bay. A comprehensive test of mapping methodology has been comple-
ted for a small study area on the eastern shore of the Bay.
Archival photography has been collected and evaluated for use-
fulness in determining trends in SAV distrivution. Two study
areas have been mapped and planimetered showing acreage esti-
mates by year.
Problems Encountered
No major problems were encountered during the project.
Approximately 14% of the Bay could not be photographed due to
military restrictions in the area. Field work was substituted
SAV 4.2
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for photography in these areas to produce maps.
Data Results and Evaluations
A. Aerial Photography.
Prior to the onset of the project 137 flight lines were
plotted on 1:250,000 U.S. Geological Survey maps. The lines
were plotted to give 20% side lap and 60% end lap. Approximate-
ly 1780 flight line kilometers were planned. It was not
possible to fly 14 flight lines totalling approximately 14% of
the planned coverage due to continued flying restrictions of
the Patuxent Naval Air Station. Sea plane time was utilized to
obtain distribution information where photographs were not
available. Supplemental Photography was obtained in the Poto-
mac River due to persistent water quality problems during good
photographic days.
Black and white photography was obtained at a scale of
1:24,000 commending on June 11, 1978 and continuing through
early October. Negatives were sent to Precision Photo Labora-
tories in Dayton, Ohio for processing, Negatives were annota-
ted and returned to the same laboratory for print production.
Negatives were exposed to bring out detail in the water for
optimum interpretation of SAV beds on the prints. The result
was over 1000 photographs annotated according to flight line
SAV 4.3
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number and photo number. These were found to be very useful in
plotting the distribution of SAV in much of the project area.
Another result of the aerial photography flown in early
June was the observation of a biomodal distribution pattern for
SAV when this photography was compared with field data collected
in July. The June photography shows full distribution of
Zannichellia palustris but not Ruppia maritima which achieved
full distribution in July. Those areas which contained
Z_. pallustris in June were deficient in that species in July.
B. Intensive study areas.
The result of the Intensive Study Area Project conducted
during the 1978 distribution inventory was that 1:6,000 scale
color photography flown during ideal tide, sun angle, turbidity
and wind conditions was required for management level mapping.
The Intensive Study Area Project was designed to determine which
film and scale would best provide percent cover and speciation
information. Color and black and white photography was flown
at three scales (1:3,000, 1:6,000 and 1:12,000) under suitable
sun angle, tidal and turbidity conditions in two areas where
maximum distribution was occurring and percent cover classes
and species associations were known (from seaplane ground truth),
The areas were Parsons Island and Queenstown. Interpretation
SAV 4.4
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of all six sets of photos have demonstrated that:
.Color photography is superior to black-and white at the
lower two altitudes for differentiation of SAV species.
At 1:12,000, speciation is not interpretable on color or
black-and-white.
.Percent cover classes are proportionately more interpre-
table as the scale increases.
.Distribution delineation accuracy increases as the scale
of the photography increases.
.The minimum mapping unit dimensions decrease as the scale
of^the photography increases.
.The minimum mapping unit dimensions decrease as the scale
of the photography increases. The minimum mapping unit
of 0.1 x 0.25 inches on the map ranges from 25 x 63 feet
to 75 x 188 feet on the ground depending upon scale.
Smaller beds are interpretable but percent cover and species
association information is not interpretable nor can it be
recorded without undue map clutter.
C. Map Production.
Submerged aquatic vegetation was mapped where established
as present by aerial photographer and/or field study. The map
base was U.S. Geological Survey 1:24,000 quad sheet mylars. A
total of seventy seven (77) sheets covered the project area.
5AV 4.5
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A photo-copy of one map is included in this report. The mini-
mum mappable bed size was approximately 0.25 hectares. There
were sixteen (16) quad sheets with no mappable vegetation present
and twenty four (24) sheets that had less than ten (10) hectares
of mappable vegetation. It was interesting to note that the
forty (40) sheets with less than ten (10) hectares of vegetation
eleven (11) vere north of the Chester/Magothy Rivers and twenty
one (21) were south of the Chaptank/upper Patuxent Rivers to
Smith Island on the eastern shore. This would indicate that the
mid-portions of tha Chesapeake Bay were relatively healthy with
regard, to distribution of submerged vegetation. This area of
the Bay also contained the highest diversity of submerged vege-
tation.
Diversity declined rapidly from eight to two or three
species in the southern portion of the eastern shore where 7L.
palustris and R, saaritima predominated. There were only a few
sinaLl areas of Zostera marina found in the lower Bay, those
being in the south marsh Island area.
U. Archival Photographic Study.
Aerial photographs were located which spanned a period of
3& years. These data were initially scanned to determine use-
fulness for SAV distribution. The lower portion of the Bay from
SAV 4.6
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the Choptank River down was eliminated for study due to lack of
consistently good data. Three sites were selected in the upper
bay for a more detailed investigation. These sites encompassed
the Chester River area, the Eastern Bay area and one site on the
Western shore to include the Gunpowder River, Salt Peter and
Seneca Creeks.
Table 1 shows trends in distribution of SAV at the three
sites. As can be seen the Eastern Bay site had the least useable
data and the Chester River site the most. Trends in the Chester
River area indicate fluctuation in distribution with time. The
1960-1970 time period shows a comparably higher distribution,
probably due to the "bloom" of Myriophyllum spjcatfrna over the , "
whole Bay. There was a decline after that period particularly
in the late 1972 data which show the effects of a huricane during
June. There is an encouraging increase in distribution shown
in the 1978 survey.
The Eastern Bay area site had very little data available
for ascertaining distribution. There does appear to be a down-
ward trend from 1970- to 1978. The Gunpowder River area site
was selected due to the presence of a thermal power generating
station which discharges heated water into Salt Peter Creek.
Operation began in 1962. SAV distribution data prior to (1960)
SAV 4.7
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and after beginning of operation (1964) indicate a relatively
stable situation. This was however, the time of Myriophyl-um
"blooms" and may mask the absence of other more thermally sen-
sitive species. There also appears to be a downward trend in
distribution from 1970-1978.
SAV 4.8
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Table 1. Shows trends in extent of submerged vegetation dis-
tribution (Acres) at three sites.
DATE CHESTER RIVER EASTERN BAY GUNPOWDER RIVER/
SALT PETER, SENECA
CRS.
1936 3478
1937 2170
1952 1900 926
1957 2548 802
1960 2890 2173
1963 3480
1964 2194
1965 2315
1969 3870
1970 4032 1470 734
1971
1972 1555
1978 3100 1215 568
SAV 4.9
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Identifiable Products to Date
1. Aerial photographic coverage for 86% of the Maryland portion
of the bay
2. Seventy seven (77) maps showing SAV distribution as of 1978.
3. Trends in distribution for three areas.
4. Archival photographic data banks for the upper Chesapeake Bay.
Anticipated Activities
Complete writing of final report
Suggested modifications
None are anticipated at this time due to the near termination
of the project.
Recommended Future Research
Based on the conclusions of this project, we could propose the
following as research that is needed regarding the distribution
of SAV in Chesapeake Bay.
1. A broad survey such as the one just completed should be sys-
tematically conducted probably on a three year cycle.
2. A system should be divised to choose high value areas where
SAV distribution could be conducted more frequently. More
detailed information on species composition, biomass and seasonal
growth characteristics should be obtained.
3. The environmental parameters of light and temperature should
be investigated at a number of locations to ascertain critical
SAV 4.10
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ranges of these variables for optimum SAV growth and reproduc-
tion.
SAV 4.11
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. -,.
.
'
SAV 4.12
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NOTES
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DISTRIBUTION AND ABUNDANCE OF SUBMERGED AQUATIC
VEGETATION IN THE LOWER CHESAPEAKE BAY - 1979
PRINCIPAL INVESTIGATOR(S); PROJECT NUMBER;
Robert J. Orth X-003201-01
PERFORMING ORGANIZATION: EPA PROJECT OFFICER;
Department of Invertebrate Ecology Thomas Nugent
Virginia Institute of Marine Science
Gloucester Point, VA 23062
BUDGET: PROJECT PERIOD:
EPA Share $18,436* Begin - 6/01/79
Performing Organization End - 5/31/81
Share 1,214
TOTAL $ 19,650
OBJECTIVES:
This project continues the research of grant number R805951
and will: (1) identify those areas in the Lower Chesapeake Bay that contain
stands of SAV with emphasis on the saline regions, (2) obtain high-quality
aerial imagery of those areas that contain significant SAV, (3) delineate SAV
species type and distribution in areas which have dense SAV, and (4) determine
if significant alterations have occurred in comparison to the similar study
conducted in 1978. This work is similar to work performed by the Chesapeake
Bay Foundation (grant number X-00-3202-01) for the Maryland portion
of the Bay.
SCIENTIFIC APPROACH:
The survey will be conducted in two phases. The initial phase will
survey the Lower Bay to identify areas containing SAV. Areas with significant
coverage (greater than 10 percent) will be noted for inclusion in the second
stag'e. The second stage will photograph the SAV in the significant zones at
an image scale of 1:24,000. Corroborative surface missions will be conducted
in areas shown to have SAV coverage in excess of 40 percent. Species present,
abundance, sediment type, and salinity will be recorded. Representative
specimens will be submitted to the National Herbarium for confirmation of
species. Data will be mapped on USGS topographic quadrangles, and the area
of SAV beds computed. The 1979 data will be compared to data collected in
1978 to identify changes in SAV distribution and will aid in the design of
the 1980 distribution and abundance project.
PRODUCTS:
Study products include maps of SAV for 1979 with supporting documentation
and changes in SAV that have occurred between 1978 and 1979.
Represents Ist-year funding of a 2-year project.
SAV 5.1
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DISTRIBUTION AND ABUNDANCE OF
SAV IN THE LOWER CHESAPEAKE BAY, VIRGINIA - 1978
PRINCIPAL INVESTIGATOR(s) ; PROJECT NUMBER;
Robert J. Orth R805951
PERFORMING ORGANIZATION: EPA PROJECT OFFICER:
Department of Invertebrate Ecology William Cook
Virginia Institute of Marine Science
Gloucester Point, VA 23062
BUDGET: PROJECT PERIOD:
EPA Share $68,681 Begin - 6/01/78
Performing Organization End - 8/15/79
Share 4,066
TOTAL $72,747
OBJECTIVES:
There are three project objectives: (1) to map the present distribution
of SAV beds in the saline portions of the Bay in Virginia, (2) to determine
changes in SAV distribution in parts of the Lower Bay over a 40-year period,
and (3) to map SAV distribution in selected freshwater portions of the
subestuaries. A companion study (grant number R8055977, page 35) is being
conducted by The American University.
SCIENTIFIC APPROACH:
Mapping of present distributions is performed from aerial photography
of all SAV beds in the saline Lower Bay at a scale of 1:24,000. A single
demonstration study of freshwater species of SAV in selected turbid freshwater
portions of the subestuaries is included. Species differentiations and
environmental conditions are verified through surface examinations of represen-
tative SAV beds utilizing skindiving observations on selected transects.
Historical aerial photography for a maximum of six saline areas and possible
freshwater areas, obtained for years from 1937 to 1977, is compared with the
new photography to assess trends.
PRODUCTS:
Products include a report and a series of maps of the Lower Chesapeake
Bay showing: (1) present distribution and abundance of SAV, (2) acres of SAV
in the Lower Chesapeake Bay, and (3) trends of historical SAV changes in
selected areas.
SAV 5.2
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Distribution and Abundance of Submerged Aquatic Vegetation
(SAV) in the lower Chesapeake Bay (X-003201)
Robert Orth
Ken Moore
Hayden Gordon
Virginia Institute of Marine Science
Gloucester Point, Virginia 23062
Objectives of Studies
- To identify those areas in the lower Chesapeake Bay that contain
stands of SAV with emphasis on the saline regions.
- To obtain aerial imagery of areas that contain significant stands of
SAV.
- To delineate SAV species type and distribution in areas which have
dense stands of SAV.
- To determine significant alterations in the distribution of SAV
compared with similar data collected in 1978.
1. Current Work Status
The major activity since the grant was started was some preliminary
overflights to identify those areas with significant stands of SAV as well
as obtaining surface information for specific areas.
2. Project Progress to Date:
The progress of the project is behind schedule because of delays in
obtaining aerial photography (see 3).
SAV 5.3
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3. Problems and Difficulties Encountered and Remedial Action Taken;
The major problem we have encountered has been the weather. Our
missions for obtaining the photography are governed by a series of general
guidelines outlining weather conditions that must be present before the
flight (e.g. low tide, sun angle, turbidity, wind, atmospherics, plant
growth). If any one condition presents serious complications for obtaining
adequate imagery of the SAV beds, the mission is aborted. These conditions
are generally optimum in early summer. Since the granting of this contract,
we have been in a standby mode because cloud cover or atmospheric haze have
been below acceptable levels during periods of low tidal stage and low sun
angle. Since the major portion of our work depends on this aerial photog-
raphy, we have only conducted aerial reconnaissance and surface field studies
to date.
4. Preliminary Data Results and Evaluations
The preliminary overflights have revealed beds of SAV to be located in
areas previously identified in 1978 to have large stands of SAV. Surface
information corroborated these facts as well as the presence of similar
species identified from 1978.
5. Identifiable Products to Date;
None.
6. Anticipated Activities;
Our objectives in the next six months will be to obtain aerial
photography as soon as weather conditions permit and complete the remainder
of the objectives of this contract. Historically, the weather clears up
considerably during the late summer - early fall period, while the density
of SAV allows for suitable delineation of the beds.
SAV 5.4
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7. Suggested Modifications;
We recommend that the granting agency be aware that the aerial
photography should be completed by June of each year to meet optimum
weather condition and that contracts be awarded in time to take this into
consideration.
8. Recommended Future Research;
Our major recommendation is that SAV be photographed on an annual basis,
primarily in the early summer period to coincide with maximum standing crop
of SAV. Mapping of all SAV, however, could be done every 2-3 years to detect
significant alterations of any stands of SAV and if any major alterations
were noted, the imagery from previous unmapped years could be checked.
We recommend that the distribution and abundance of SAV in the entire
York and Rappahannock rivers be mapped for historical data as indicated in
our previous report for only small sections. Related to this would be
investigations into fish and crab statistics for each river system as it
relates to the abundance of SAV and the possible implications of the
relationship between SAV abundance and abundance of blue crabs.
SAV 5.5
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