Chesapeake Bay
                        Chesapeake Bay Program
Oxyrhina desori

                            Kathryn Reshetiloff
                       Illustrations and layout
                             Sandra Janniche
                              Richard Batiuk
                             Peter Bergstrom
                              Carin Bisland
                             Walter Boynton
                              Sherri Cooper
                              Eugene Cronin
                             Richard Everett
                              Douglas Forsell
                          Eileen Setzler-Hamilton
                            Michael Hirshfield
                              Carl Hershner
                            Frederick Howard
                              Steven Jordan
                             Robert Lippson
                               Lori Mackey
                            Tamara McCandless
                             Kent Mountford
                              Kate Naughten
                               Robert Orth
                              Nita Sylvester
                            Christopher Victoria
17.5. Environmental     Chesapeake       Department of     U.S. Fish and
Protection Agency     Bay Program       the Interior     Wildlife Service
                              Printed by the
                    U.S. Environmental Protection Agency
                                  for the
                          Chesapeake Bay Program

                               APRIL 1995

                         Printed on Recycled Paper

                                    TABLE OF CONTENTS
                     fee Watershed
                  » Chesapeake Bay - An Important Resource
                    .4 Threatened Resource
« Geologic History
• The Chesapeake Bay
4 Erosion and Sedimentation

• Water Salinity, Temperature and Circulation
» Suspended Sediments: Composition and Effects
• Chemical Make-up
                    Islands and Inlands
                    Freshwater Tributaries
                  * Shallow Water
                  « O/w?»
                  » Wetlands
                  « Submerged Aquatic Vegetation
                  » Plankton
                  « The Swimmers
                  • Z//e «/ //ie Bottom

                  » Direct and Detrital Pathways

                  • Be Part of the Solution, Not Part of the Problem
                  » For More Information






                                                     5 J.S. EPA Region III
                                                     Regional Center for Environmental
                                                     1650 Arch Street (3PM52)
                                                     Philadelphia, PA 19103

               \  THE CHESAPEAKE BAY

Chesapeake  Bay  Ecosystem
The physical processes that drive the Bay eco-
system sustain the many habitats and
organisms found there. Complex relation-
ships exist among the living resources of the
Chesapeake Bay watershed. Even the small-
est of creatures plays a vital role in the overall
health and production of the Bay. Forests and
wetlands around the Bay and the entire wa-
tershed filter sediments and pollutants while
supporting birds, mammals and  fish. Small
fish and crabs find shelter and food among
lush beds of submerged aquatic vegetation.
Unnoticed by the naked eye, phytoplankton
and microzooplankton drift with the cur-
rents, food for copepods and small fish. Clams and
oysters pump Bay water through their gills, filtering out
both plankton and sediment. During the fall and winter,
waterfowl by the thousands descend upon the Bay, feed-
ing in wetlands and  shallow waters. Bald eagles and
ospreys, perched high above the water, feed on perch,
menhaden and other small fish to their young. The spec-
trum of aquatic environments, from freshwater to
seawater, creates a unique ecosystem abundant with life.

The relentless encroachment of people threatens the
ecological balance  of the Chesapeake Bay. Fifteen mil-
lion people live, work and play in the watershed. Each
individual directly affects the Bay by adding waste, con-
suming resources and by changing the character of the
land, water and air that surrounds it. However, through
the choices we make in our everyday lives, we can lessen
our impact on the Bay's health. We must nurture what
Aldo Leopold once termed as our "wild rootage" - a
                               BAY FACT:
recognition of the fundamental connection
and dependency between society and the en-
vironment. As advocates for the Bay and its
many living resources, we can preserve the
Chesapeake for years to come.

* The Watershed
                                              The Chesapeake Bay receives about half its
                                              water volume from the Atlantic Ocean. The
                                              rest drains into the Bay from an enormous
                                              64,000 square-mile drainage basin or water-
                                              shed. The watershed includes parts of New
                                              York, Pennsylvania, West Virginia, Delaware,
                                     Maryland and Virginia and the entire District of Colum-
                                     bia. Freshwater from springs,  streams, small creeks and
                                     rivers flows downhill mixing with ocean water to form
                                     this estuarine system. Soil, air,  water, plants and animals,
                                     including humans, form a complex web of interdepen-
                                     dencies that together make up this Chesapeake ecosystem.
                                     The 15 million people living  in the Chesapeake water-
                                     shed play an important role in this ecosystem. The
                                     activities and problems occurring throughout the entire
                                     watershed significantly impact the functions and relation-
                                     ships of the  Bay proper. We must choose whether our
                                     role will be destructive or productive.

                                     * Chesapeake Bay - An Important Resource

                                     Through the years, residents and visitors alike have found
                                     the Chesapeake imposing yet hospitable. The Algonquin
                                     Indians called it "Chesepiooc," meaning great shellfish
                                     bay. Spanish explorers described Chesapeake Bay as "...the
             POPULATION PROJECTIONS: Chesapeake Bay Watershed

       02     4     6      8     10    12     14     16    18

Waterman handtonging
     for oysters.
   best and largest port in the world." Captain
   John Smith, an English explorer, extolled, "The
   country is not mountainous nor yet low but
   such pleasant plain  hills and fertile val-
   leys...rivers and brooks, all  running  most
   pleasantly into a fair Bay." All were impressed
   with its size, navigability and abundance of
   wildlife and food.
  Prior to the late
1800s, oysters were
 so abundant that
 some oyster reefs
posed navigational
 hazards to boats.
           the Chesapeake. An extensive finfish indus-
           try, primarily based on menhaden and striped
           bass, rounds out the Chesapeake's commer-
           cial seafood production. In 1992, the
           dockside value of commercial shellfish and
           finfish harvests was close to $80 million.
   Today, the Chesapeake is still one of this
   country's most valuable natural treasures. Even
   after centuries  of intensive use, the Bay re-
   mains a highly  productive natural resource. It supplies
   millions of pounds of seafood, functions as a major hub
   for shipping and commerce, provides natural habitat for
   wildlife and offers a variety of recreational opportunities
   for residents and visitors.

   Oysters and blue crabs are famous Chesapeake Bay deli-
   cacies. From the 1920s to the 1970s, the average annual
   oyster catch was about 27 million pounds of meat per
   year. In the last  10 years, the catch has declined dramati-
   cally due to overharvesting, disease and loss or
   degradation of  habitat. Chesapeake Bay blue  crab pro-
   duction averaged 86 million pounds annually from 1983
   to 1992, contributing more than half the nation's catch.
   Although this figure is consistent with past harvests, fish-
   ing pressure, both commercial and recreational,  continues
   to grow. The states of Maryland and Virginia have pledged
   to jointly manage the Bay's blue crab harvests through
   pot limits, gear restrictions and license restrictions. More
   than half the nation's soft-shelled clams also come from
           The hospitable climate, lush vegetation and
           natural beauty of the Chesapeake has made
 ;.-,,-, ,  .   it an increasingly popular recreational area.
' '; •',  ,   Boating,  crabbing, swimming, hunting and
           camping are major attractions. Both power
and sail boating have grown dramatically. In 1993, more
than 175,000 pleasure craft were registered.

Sportfishing is another major recreational activity in the
Chesapeake. The National Marine Fisheries Service re-
ported that close to 1 million anglers from Maryland and
Virginia took almost 600,000 fishing trips in 1991. Recre-
ational fishing in the states of Maryland and Virginia is
estimated at more than $ 1 billion per year.

H. L. Mencken once called the Bay,  "...a great  outdoor
protein factory." A study by the National Marine Fisher-
ies Service ranked the Chesapeake as third in the nation
in fishery catch. Only the Atlantic and Pacific oceans ex-
ceed the Bay in production. That is an impressive ranking,
since the Bay is small  compared to these other bodies
of water.

The Chesapeake is also a key commercial waterway, with
two of the nation's five major North Atlantic ports located

here. The Hampton Roads Complex, which includes
Portsmouth, Norfolk, Hampton and Newport News,
dominates the mouth of the Bay. Hampton Roads
ranks third in tonnage of foreign water-borne com-
merce. At the northern end, the Port of Baltimore
is ranked ninth in the  nation.  Baltimore is the
leading exporter of trucks and cars in the na-
tion. More than 90 million tons of cargo were
shipped via the Chesapeake during 1992. Both
Baltimore and Hampton Roads are near the
coal-producing regions of Appalachia, making
them essential to exporting U.S. coal abroad. The
Hampton Roads Complex already leads the na-
tion in exporting coal and lignite.

Shipbuilding and other related industries also
depend on the Bay. Industries and power com-
panies use large volumes of water from the Bay
for industrial processes and cooling.

Perhaps the Chesapeake's most valuable function,
yet most difficult to put a price tag on, is its role as
habitat for living resources. The Chesapeake Bay and
its surrounding watershed provide homes for a
multitude of plants and animals.

waterfowl and other birds migrating along
the Atlantic Flyway stop here, finding
food and shelter in the many coves and
marshes. The Chesapeake is the win
ter home for tundra swans, Canada
geese and a variety of ducks, includ-
ing canvasbacks, pintails, scoters,
eiders and ruddy ducks. Between
1992 and 1994,  an average  of
28,000 swans, 300,000 geese and
650,000 ducks wintered on the Bay.
It is also a major  nesting area for the
threatened bald eagle.  The nation's largest population
of another raptor,  the osprey, is in the Bay region.

The Chesapeake's tidal freshwater tributaries provide
spawning and nursery sites for several important spe-
cies of fish, such as white and yellow perch, striped
bass, herring and shad. During the warmer months,
numerous marine species, including bluefish, weakfish,
croaker, menhaden, flounder and spot, enter the Bay to
feed on its rich food supply.

* A Threatened Resource

Chesapeake Bay, the largest estuary in the United States,
is part of an extremely productive and complex eco-
                            BAY FUN FACT:
           Canada goose
         (Branta canadens/'s)  '"
                             (Aythya valisineria)
1 (Pandion haliaetus)
                    Great blue heron
                    (Ardea herodias)
             Tundra swan
          (Cygnus columbianus)

system. This ecosystem consists of the Bay, its tributar-
ies and the living resources it supports. Humans, too,
are a part of this ecosystem. We are beginning to under-
stand how our activities affect the Bay's ecology. Growing
commercial, industrial, recreational and urban activities
continue to threaten the Bay and its living resources.

Overharvesting and loss of habitat threatens fish and
shellfish species. These two factors, plus disease, have
decimated the oyster population. Excess sediment and
nutrients endanger the Bay's water quality. Hypoxia (tow
dissolved oxygen) and anoxia (absence of dissolved oxy-
gen) are particularly harmful to bottom-dwelling
(benthic) species. Toxic substances, particularly high in
industrialized urban areas, accumulate in the tissues of
birds, fish and shellfish.

To find the causes of and potential remedies for these
problems, it is necessary to see the Bay from an ecologi-
cal perspective. All too often we think of ourselves as
external to our environment and ignore the many rela-
tionships that link people, other living creatures and the
surrounding habitat.  If we ignore these connections
when seeking solutions to problems,  more and greater
problems may result.
For example, agricultural activities and residential de-
velopment increase  the amount of sediment and
nutrient-rich fertilizers entering the Bay through run-
off. Water clarity is reduced and rivers are silted in.
Excess nutrients cause algae blooms that block sunlight
from reaching critical bay grasses known as submerged
aquatic vegetation or SAV. As SAV declines, so does the
food, shelter and nursery grounds for many aquatic spe-
cies. Solutions to these environmental problems can only
be effective if complex relationships among all compo-
nents of the ecosystem are also considered.

When environmental problems are approached from an
ecosystem perspective, both living and non-living com-
ponents are considered when recommending solutions.
A truly effective solution not only corrects the prob-
lem, but avoids damaging other relationships within the
ecosystem. This approach makes problem-solving a great
deal more challenging, but leads to more effective envi-
ronmental management.
                   BAY FACT:

          Geology  of the  Chesapeake
The Chesapeake Bay as we know it today is
the result of thousands of years of continu-
ous change. The Chesapeake, less than
10,000 years old, continues to change.
Nature, like a dissatisfied artist, is con-
stantly reworking the details. Some
modifications enhance the Bay; oth-
ers harm it. All  affect the ecosystem
and its interdependent parts.  Some
changes are abrupt;  while others take
place over such a  long time that we can
only recognize them by looking back into
geologic history.
Humans are becoming more involved
in the reshaping process, often inadvert-
ently initiating chains of events that
reverberate through the Bay's ecosystem.
Because our actions can have devastating ef-
fects on the entire system, it is essential that
we develop an adequate understanding  of
the Bay's geological makeup and funda-
mental characteristics.

» Geologic History

During the latter part of the Pleistocene ep-
och (which began one million years ago), the
region that is now the Chesapeake was al-
ternately exposed and submerged as
massive glaciers  advanced and re-
treated up  and down the North
American continent. Sea levels rose
and fell in concert with glacial con-
traction and expansion. The region
still experiences small-scale changes in
sea levels, easily observed over the du-
ration of a century.
The most recent retreat of the glaciers,
which began about 18,000 years ago,
marked the end of the Pleistocene ep-
och and brought about the birth of the
Chesapeake Bay. The rising waters
from melting glaciers covered the con-
tinental shelf and reached the mouth
of the Bay about 10,000 years ago. Sea
level continued to rise, eventually sub-
merging the Susquehanna River Valley.
A Broad ribbed scallop
  (Lympecten santamar/a)
B Turret snail (Jurritella plebia)
C Ark (Anadora staminea)
D Shark teeth
  1  (Otodus obliquus)
  2  (Hemipristis serra)
  3  (Oxyrhina desori)
                   The Bay assumed its present dimensions about
                    3,000 years ago. This complex of drowned
                       streambeds formed the Chesapeake basin
                         we know today.

                          • The Chesapeake Bay

                          The Bay proper is approximately 200
                         miles long but contains more than 4,400
                       miles of shoreline. The Bay ranges in width
                      from about 4 miles near Annapolis, Mary-
                        land, to 30 miles at its widest point, near
                          the mouth of the Potomac. The water
                          surface area of the tidal Bay encom-
                           passes more than 2,300 square miles;
                           include the tributaries and that figure
                          nearly doubles.
                       Fifty major tributaries pour water into the
                       Chesapeake every day. Almost 85-90 per-
                        cent of the freshwater entering the Bay
                        comes from the northern and western
                        sides. The remaining 10 to 15 percent is
                        contributed by the eastern shore. Nearly
                        an equal volume of saltwater enters the
                        Bay from the ocean.
  On average, the Chesapeake holds
  about 18 trillion gallons of water. Al-
 though the Bay's length and width are
dramatic, the average depth is only 27
 feet. The Bay is shaped like a shallow
  tray, except for a few deep troughs
   believed to be remnants of the an-
   cient Susquehanna River. The
  troughs form a deep channel along
 much of the length of the Bay. This chan-
 nel allows passage of large commercial
 vessels. Because it is so shallow, the
  Chesapeake is far more sensitive to
  temperature fluctuations and wind
  than the open ocean.

  To adequately define the Chesapeake
  ecosystem, we must go far beyond the
  shores of the Bay itself. Although the
  Bay lies totally within the Atlantic
  Coastal Plain, the watershed includes
  parts  of the  Piedmont Plateau  and

        Jr^T V U-i
                                                                                        BAY FACT:
fcl>"7.1 Appalachian Province
[[[I] [HI Piedmont Plateau
|    | Atlantic Coastal Plain
Appalachian Province. The tributaries provide a mix-
ture of waters with a broad geochemical range to the
Bay. These three different geological provinces influ-
ence the Bay. Each contributes its mixture of minerals,
nutrients and sediments.

The Atlantic Coastal Plain is a flat, low land area with a
maximum elevation of about 300 feet above sea level. It
is supported by a bed of crystalline rock, covered with
southeasterly-dipping wedge-shaped layers of relatively
unconsolidated  sand, clay  and gravel.  Water passing
through this loosely compacted mixture dissolves many
of the minerals. The most  soluble elements are  iron,
calcium and magnesium.

The Atlantic Coastal Plain extends from the edge of the
continental shelf, to the east, to a fall line that ranges
from 15  to 90 miles west of the Bay. This fall line forms
the boundary between the Piedmont Plateau and the
Coastal Plain. Waterfalls and rapids clearly mark this line,
                                   which is close to Interstate 95. Here, the el-
                                   evation rises to 1,100 feet.  Cities such as
                                   Fredericksburg and Richmond  in Virginia, Bal-
                                 timore in Maryland, and  Washington,  D.C.
                               developed along the fall line, taking advantage of the
                             potential water power gen-
                            erated by  the falls. Since
                            colonial ships could not sail
                            past the fall line,  cargo
                            would be transferred to ca-
                            nals or shipped overland.
                            Cities along the fall line be-
                            came important areas  for

                            The Piedmont Plateau ranges from the fall line in the
                            east to the Appalachian Mountains in the west. This area
                            is divided into two geologically distinct regions by Parrs
                            Ridge, which traverses Carroll, Howard and Montgom-
                             ery Counties in Maryland and adjacent counties in
                               Pennsylvania. Several types of dense crystalline rock,
                                including slates, schists, marble and granite, com-
                                pose  the eastern side. This results in a very diverse
                               topography.  Rocks of the Piedmont tend to be im-
                              permeable and water from the eastern side is low in
                             calcium  and magnesium salts. This makes the water soft
                            or easy to lather.

                            The western side of the Piedmont consists of sandstones,
                            shales and siltstones, underlain by limestone. This lime-
                            stone bedrock contributes calcium and magnesium to
                            its water, making it hard. Waters from the western side
                            of Parrs Ridge flow into the Potomac River, one of the
                            Bay's larger tributaries.

                            The Appalachian Province lies in the western and north-
                            ern parts of the watershed. Sandstone, siltstone,  shale
                            and limestone form the bedrock. These areas,  charac-
                            terized by mountains and valleys,  are rich in coal and
                            natural gas  deposits. Water from this province flows to
                            the Bay mainly via  the Susquehanna River.

                            The waters that flow into the Chesapeake Bay have dif-
                            ferent chemical identities that depend on the geology
                            of their place of origin. In turn, the nature of the Bay
                            itself depends on the characteristics and relative volumes
                            of these contributing waters.

                             »  Erosion and Sedimentation

                            Since its  formation, the Bay's shore has undergone con-
                            stant modification by erosion, transport and deposition
                            of sediments. In this process, areas of strong relief, like

peninsulas and headlands, are eroded and smoothed by
currents and tides, and the materials are deposited in
other parts of the Bay. Sediments may be deposited in
channels. Sediments, carried by the river currents, are
also left at the margins of the Bay and major tributaries,
resulting in broad, flat deposits of mud and silt. Coloni-
zation of these  areas by hydrophytic (water-loving)
vegetation may stabilize the sediments, and wetlands can
develop. Recently however, wetlands along shorelines are
retreating inland as sea level rises. The speed at which
these modifying processes progress depends on numer-
ous factors, including weather, currents, composition of
the affected land, tides, wind and human  activities.

Many of the islands that existed in the Bay during colo-
nial times are now submerged. Poplar Island, in Talbot
County, Maryland, illustrates the erosive forces continu-
ing today. In the early 1600s, the island encompassed
several hundred acres. Over the centuries, rising sea level
eroded the perimeter of Poplar Island. Though still popu-
lated by the 1940s, only 200 acres remained and the island
had been cut in two. Today, a chain of small islands is all
that remains of the original Poplar Island. Efforts are un-
derway to stabilize the remnant 100 acres. In addition,
the island's original landmass will be rebuilt by creating
marshes that will protect the island form further ero-
sion and provide a haven for birds and other wildlife.

In contrast, sedimentation has also altered the landscape.
By the mid 1700s some navigable rivers were filled in by
sediment as more land was cleared for agriculture.
Joppatown, Maryland, once a seaport, is now more than
2 miles from water. The forces of erosion and sedimen-
tation continue to reshape the details of the Bay.
                                                                               Mid-19th Century
                                                                                 725 acres
                                                                                 Late 1940's
                                                                                 200 acres

                                                                              Today's Remnants
                                                                               100-125 acres

      Water  & Sediments
Water ... approximately 70 percent of the earth's sur-
face is covered by it. It makes up approximately 80
percent of our total body weight. Without it, we cannot
live. Perhaps, because its presence is so pervasive in
our lives, we tend to think of water as homogeneous
rather than a substance with extremely diverse charac-
teristics and properties.

In the natural environment, water is never pure. It tends
to hold other substances in solution and easily enters
into various chemical reactions. As the universal solvent,
water is an important environmental medium. Water
normally contains dissolved gases, such as oxygen, and
a variety of organic (containing carbon) and inorganic
materials. The concentration and distribution of these
substances can vary within a single body of water. Add
differences in temperature and circulation, which can
enhance or retard certain chemical reactions, and the
variety of possible water environments vastly increases.

Of all bodies of water, estuarine systems offer the great-
est physical variability in water composition. An estuary,
according to oceanographer Donald W. Pritchard, is a
"...  semi-enclosed body of water which has free con-
nection with the open sea and within -which sea water
is measurably diluted by freshwater from land drainage."
Within an estuary, freshwater mixes with salt water, with
each contributing its own chemical and physical char-
acteristics. This creates a range of environments that
supports a wide variety of plants and animals.

* Water: Salinity, Temperature
  and Circulation

The distribution and stability of an estuarine ecosystem,
such as the Chesapeake Bay, depends on three impor-
tant physical characteristics of the water: salinity,
temperature and circulation. Each affects and is affected
by the others.

Salinity is a key factor affecting the physical make-up of
the Bay. Salinity is the number of grams of dissolved salts
in 1,000 grams of water. Salinity is usually expressed in
parts per thousand (ppt). Freshwater contains few salts
(less than 0.5 ppt) and is less dense than full strength
seawater which averages 25-30 ppt. Salinity increases
with depth. Therefore, freshwater tends to remain at
the surface.
  in parts per

                                     in parts per
             Isohalines mark the salt content of surface water. The salinity gradient varies during the year
             due to freshwater input: fresher during spring rains, saltier during the drier months of autumn.

  Seawater from the Atlantic Ocean enters the mouth of
  the Bay. Salinity is highest at that point and gradually de-
  creases as one moves north. Salinity levels within the
  Chesapeake vary widely; both seasonally and from year
  to year, depending on the volume of freshwater flowing
  into the Bay. On a map, isohalines or salinity contours
freshwater from the north and salt water from the south.
Circulation causes nutrients and sediments to be mixed
and resuspended. This mixing creates a zone of maxi-
mum turbidity that, due to the amount of available
nutrients, is often used as a nursery area for fish and
other organisms.
 mark the salt content of surface waters. Because the great-
 est volume of freshwater enters the Bay from northern
 and western tributaries, isohalines tend to show a south-
 west to northeast tilt. The rotation of the earth also drives
 this salinity gradient. Known as the Coriolis force, it de-
 flects flowing water to the right in the Northern
 Hemisphere so that saltier water moving up the Bay is
 deflected towards the Eastern Shore.

 Temperature dramatically changes the rate of chemical
 and biological reactions within the water. Because the
 Bay is so shallow, its capacity to store heat over time is
 relatively small. As a result, water temperature fluctuates
 throughout the year, ranging from 0-29 C° (32-84 F°).
 These changes in water temperature influence when
 plants and animals feed, reproduce, move locally or mi-
 grate. The temperature  profile of the Bay is fairly
 predictable. During spring and summer, surface and shal-
 low waters are warmer than deeper waters with the
 coldest water found at the bottom. Often turbulence of
 the water helps to break down this layering.

Just as circulation moves much needed blood throughout
 the human body, circulation of water transports plank-
 ton, fish eggs, shellfish larvae, sediments, dissolved
 oxygen, minerals and nutrients throughout the Bay. Cir-
 culation is driven, primarily,  by the  movements of
                         Weather often disrupts or re-
                         inforces this two-layered
                         flow. Wind plays a role in the
                         mixing of the Bay's waters.
                         Wind can also raise or lower
                         the level of surface waters
                         and occasionally reverse the
                         direction of flow. Strong
                         northwest winds, associated
                         with high pressure  areas,
                         push water  away from  the
                         Atlantic Coast, creating ex-
                         ceptionally low tides. Strong
northeast winds, associated with low pressure areas, pro-
duce exceptionally high tides.

Together, salinity, temperature and circulation dictate
die physical characteristics of water. The warmer, lighter
freshwater flows seaward over a layer of saltier and denser
water flowing upstream. The opposing movement of
these two flows forms saltwater fronts or gradients that
move up and down the Bay in response to the input of
freshwater. These fronts are characterized by intensive
mixing. A layer separating water of different densities,
known as a pycnocline, is formed. This stratification var-
ies within any season depending on rainfall. Stratification
is usually highest in the spring as the amount of freshwa-

   The change in temperature and salinity divides the Bay into saltier bottom
   water and lighter, fresher surface water. A blurry, mixing layer, known as
   the pycnocline, divides the two. Strong winds can pile surface water against
   one shore of the Bay. To reestablish equilibrium, the bottom layer flows
   up into shallower water.
                                                > PYCNOCLINE
                                                     SALT CONTENT
(degrees Celsius)
of freshwater in the Bay increases due to melting snow
and frequent rain. Stratification is maintained through-
out summer due to warming of surface waters.

In autumn, fresher surface waters cool faster than deeper
waters and sink. Vertical mixing of the two water layers
occurs rapidly, usually overnight. This mixing  moves
nutrients up from the bottom sediments, making them
available to phytoplankton and other organisms inhab-
iting upper water levels. This turn-over also distributes
much-needed dissolved oxygen to deeper waters. Dur-
ing the winter, water temperature  and salinity are
relatively constant from surface to bottom.

• Suspended Sediments:
  Composition and Effects

The waters of the Chesapeake and its tributaries trans-
port huge quantities of sediments. Although sediments
are a natural part of the Bay ecosystem, accumulation
of excessive amounts of sediments is undesirable. Accu-
mulation of sediments can fill in ports and waterways.
                 This sedimentation process has
                 already  caused several colonial
                 seaports, like Port Tobacco, Mary-
                 land, to become landlocked. As they
                 settle to  the bottom of the Bay, the
                 sediments can also smother the
                 bottom-dwelling plants and animals.
                 Sediments suspended in the water col-
                 umn cause the water  to  become
                 cloudy, or turbid, decreasing the light
                 available for SAV growth.

                 Sediments can also carry high concen-
                 trations  of certain toxic materials.
                 Individual sediment particles have a
                 large surface area, and many mol-
                 ecules easily adsorb, or attach,  to
                 them. As a result, sediments can act
                 as chemical sinks by adsorbing met-
                 als, nutrients, oil, pesticides and other
                 potentially toxic materials.  Thus, ar-
                 eas of high sediment deposition
                 sometimes have high concentrations
                 of nutrients, persistent (long-lasting)
                 chemicals and contaminants, which
                 may later be released.

                 In the upper Bay and tributaries, sedi-
                 ments are fine-grained silts and clays
	'   that are light and can be carried long
                 distances. These sediments are car-
 ried by the fresh, upper layer  of water. As they move
 into the Bay, the particles slowly descend into the denser
 saline layer. Here, the particles may reverse direction and
 flow back up toward tidal tributaries with the lower layer
 of water.  As the upstream flow decreases, the sediments
 settle to the bottom.

 Sediments in the middle Bay are mostly made of silts and
 clays. These sediments are mainly derived from shore-
 line erosion. In the lower Bay, by contrast, the sediments
 are sandier, and heavier. These particles result from shore
 erosion and inputs from the ocean. Sediments drop to
 the bottom fairly rapidly,  remain near their original
 source and are  less likely to be resusp ended than
 finer silts.

 * Chemical Make-up

 like temperature and salinity, the chemical composition
 of the water also helps determine the distribution and
 abundance of plant and animal life within the Bay. The
 waters of the Chesapeake contain organic and inorganic

materials, including dissolved gases, nutrients, inorganic
salts, trace elements, heavy metals and potentially toxic

The more saline waters are chemically similar to seawa-
ter. Major constituents include chlorides, sodium,
magnesium, calcium and potassium. Dissolved salts are
important to the life cycles of many organisms. Some
fish spawn in fresh or slightly brackish water and must
move to more saline waters as they mature. These spe-
cies have internal mechanisms that enable them to cope
with the changes in salinity.

Seawater also contains hundreds of trace elements that
are important in many biological reactions. For example,
living organisms require minute quantities of cobalt to
                                                    BAY FACT:
       (in parts per million)
              .95 ppm
                                     I PURE WATER
                                     I CHEMICAL MAKE-UP
    109.6 ppm
ral dissolved  materials.
These  come  from several
sources. Microorganisms,
such as bacteria, decom-
pose dead organisms and
release compounds into the
water.  Live organisms also
release compounds directly
into the water. In addition,
dissolved mater-ial enters
into the Bay via its tributar-
ies and the ocean.
                   Dissolved oxygen is essential for most animals inhabit-
                   ing the Bay. The amount of available oxygen is affected
                   by salinity and temperature. Cold water can hold more
                          dissolved oxygen than warmer water and fresh-
                          water holds more than saline water.  Thus,
                          concentrations of dissolved oxygen vary, in part,
                          with both location and time.  Oxygen is trans-
                          ferred from the atmosphere  into the surface
                          waters by diffusion and the aerating action of the
                          wind. It is also added as a by-product of photo-
                          synthesis. Floating and rooted aquatic plants and
                          phytoplankton release oxygen when photosynthe-
                          sizing.  Since photosynthesis requires light,
                          production of oxygen by aquatic plants is limited
                          to shallow water areas, usually  less than 2 meters
                          (approximately 6 feet) deep.  Surface water is
                          nearly saturated with oxygen  most of the year,
                          while deep bottom waters range from saturated
                          to anoxic (no oxygen present).
                    MAJOR COMPONENTS

   Potassium  Calcium   Sulfate   Magnesium   Sodium     Chlorine
    380 ppm   400 ppm  885 ppm  1350 ppm  10,500 ppm   19,000 ppm
              *      *
 make vitamin B-12. Metals, such as mercury, lead, chro-
 mium and cadmium, also occur in low concentrations.

 The composition of seawater is relatively constant from
 place to place. Freshwater, however, varies depending
 upon the soil and rocks the water has come in contact
 with. Both fresh and saltwater contain a myriad of natu-
                          During the winter, respiration levels of organisms
                          are relatively low. Vertical mixing is good and
                          there is little salinity or temperature stratification.
                          As a result, dissolved oxygen is plentiful through-
                          out the water column. During the spring and
                          summer, increased levels of animal and microbial
                          respiration and greater stratification may reduce
                          vertical mixing, resulting in low levels of dissolved
                          oxygen in deep water. In fact, deep parts of some
                          tributaries like the  Patuxent,  Potomac and
                          Rappahannock rivers and deep waters of the Bay's
                          mainstem can become anoxic in summer. In the
                          autumn, when surface waters cool, vertical mix-
                    ing occurs and  deep waters are re-oxygenated.

                    Carbon dioxide, another dissolved gas, is important to
                    the well-being of the Bay's aquatic environment. It pro-
                    vides the carbon that plants  use to produce new tissue
                    during photosynthesis, and  is a by-product of respira-
                    tion. Carbon dioxide  is more soluble  in water than

                                                               Excessive       Sunl'Sht
                                                              Phosphorus &
                                                             Nitrogen Inputs
                             Phosphorus &
                            Nitrogen Inputs
                                                                       Algae Bloom . .  -'
          Healthy  -/
Oyster Reef:-.?
                                                                          •- •'-.   •
oxygen. Its availability is also affected by temperature
and salinity in much the same fashion as oxygen.

Nitrogen is essential to the production of plant and ani-
mal tissue. It is used primarily by plants and animals to
synthesize protein. Nitrogen enters the ecosystem in sev-
eral chemical forms and also occurs in other dissolved
or paniculate forms, such as in the tissues of living and
dead organisms.

Some bacteria and blue-green algae can extract nitro-
gen gas from the atmosphere and transform it into
organic nitrogen compounds. This process, called ni-
trogen fixation, cycles nitrogen between organic and
inorganic components. Other bacteria release nitrogen
gas back into the atmosphere as part of their normal
metabolism in a process called denitrification. Denitri-
fication removes about 25  percent of the  nitrogen
entering the Bay each year.

Phosphorus is another key nutrient hi the Bay's ecosys-
tem. In the water, phosphorus occurs in dissolved
organic and inorganic forms,  often attached to particles
of sediment. This nutrient is essential to cellular growth
and reproduction. Phytoplankton and bacteria assimi-
late  and use phosphorus  in their growth cycles.
Phosphates, the organic form are preferred, but organ-
isms  will use  other forms of phosphorus when
phosphates are unavailable.
                                                 In the presence of oxygen, high concentrations of phos-
                                                 phates in the water will combine with suspended
                                                 particles. These particles eventually settle to the Bay bot-
                                                 tom and are temporarily removed from the cycling
                                                 process. Phosphates often become long-term constitu-
                                                 ents of the bottom sediments. Phosphorus compounds
                                                 hi the Bay generally occur in greater concentrations in
                                                 less saline areas, such as the upper part of the Bay and
                                                 tributaries. Overall,  phosphorus concentrations vary
                                                 more in the summer than winter.

                                                 Nutrients, like nitrogen and phosphorus, occur natu-
                                                 rally in water,  soil and air. Just as the nitrogen and
                                                 phosphorus in fertilizer aids in the growth of agricul-
                                                 tural crops, both nutrients are vital to the growth of
                                                 plants within the Bay.  Excess nutrients, however, are
                                                 pollutants. Sewage treatment plants, industries, vehicle
                                                 exhaust, acid rain, and runoff from agricultural, resi-
                                                 dential and  urban areas are additional sources of
                                                 nutrients entering  the Bay.

                                                 Excess amounts of phosphorus and nitrogen cause rapid
                                                 growth of phytoplankton, creating dense populations,
                                                 or blooms. These  blooms become so dense that they
                                                 reduce the amount of sunlight available to submerged
                                                 aquatic vegetation. Without sufficient light, plants can-
                                                 not photosynthesize and produce the food they need to
                                                 survive. Algae may also grow directly on the surface of
                                                 SAV, blocking light. Another hazard of nutrient-enriched

algal blooms that are not consumed by zooplankton
comes after the algae die. As the blooms decay, oxy-
gen is used up in decomposition. This can lead to
dangerously low oxygen levels that can harm or even
kill aquatic organisms.

Besides nutrients, people add other substances to the
Bay's water creating serious pollution problems. Heavy
metals, insecticides, herbicides and a variety of syn-
thetic products and by-products can be toxic to living
resources. These contaminants reach the Bay through
municipal and industrial wastewater, runoff from agri-
cultural,  urban and industrialized areas and atmos-
pheric deposition.

This situation is improving.  In some cases, industrial
wastewater is pretreated to remove contaminants. The
use of especially damaging synthetic substances, like
DDT and Kepone, has been banned.

In an effort to control nutrient pollution, the states of
Maryland, Pennsylvania and Virginia and the District
of Columbia agreed to reduce the total amount of nu-
trients entering the Bay by 40 percent by the year 2000.
Controllable sources include runoff from agricultural,
suburban and urban areas, wastewater treatment plants,
and industry. A ban on laundry detergents containing
phosphates has reduced phosphorus levels. New tech-
nologies implemented at many sewage treatment plants
remove phosphorus and some nitrogen before the efflu-
ent is discharged into rivers.  Other efforts include
maintaining forested or other vegetated buffer strips
along water sources, reducing fertilizer use on farms and
lawns and managing animal waste.
                   BAY FACT:

The Bay provides food, water, cover and nesting or nurs-
ery areas, collectively known as habitat, to more than
2,700 migratory and resident wildlife species. All plants
and animals have specific habitat requirements that must
be satisfied in order to live and thrive. Food, tempera-
ture, water, salinity, nutrients, substrate, light, oxygen
and shelter requirements vary with each species. These
physical and chemical variables largely deter mine which
species can be supported by a particular habitat.

As a highly productive estuary, the Chesapeake Bay and
its surrounding watershed provide an array of habitats.
Habitat types range from hardwood forests of the Appa-
lachian mountains to saltwater marshes in the Bay. These
habitats are influenced by climate, soils, water, plant
and animal interactions and human activities. Four ma-
jor habitat areas are critical to the survival of the living
resources of the Bay.
• Islands and Inlands

Lands that lie near water sources support
a multitude of species, from insects, am-
phibians and  reptiles to birds  and
mammals. Streambanks, floodplains and
wetlands form the transition from upland
to water. These areas act as buffers by re-
moving sediments, nutrients, organic
matter and pollutants from runoff before
these substances can enter the water. For-
ests and forested wetlands are particularly
important to waterfowl, other migratory
birds and colonial waterbirds.

Forested uplands and wetlands are nest-
ing and resting habitat for neotropical
migratory birds. These birds breed in the
United States but winter in Central and
South America. Some  neotropical birds
breed in the forests found in the Bay wa-
tershed. The Chesapeake Bay lies within
the Atlantic Flyway, a major migration
route for neotropical migrants and migrat-
ing waterfowl, and is a significant resting
area for birds.
 Surrounded by water and cut off from most large preda-
 tors, Chesapeake Bay islands are a haven for colonial
 waterbirds (terns and herons), waterfowl (ducks) and
raptors (ospreys and bald eagles). Islands can also pro-
tect submerged aquatic vegetation and shallow water
areas from erosion and sedimentation. However, islands
themselves are eroding at alarming rates, mostly due to
sea level rise and the erosive force of wind and waves.

» Freshwater Tributaries

Within the Chesapeake Bay watershed, five major riv-
ers, the Susquehanna, Potomac, Rappahannock, York
and James, provide almost 90 percent of the freshwater
to the Bay. These rivers and other smaller rivers,  along
with the hundreds of smaller creeks and streams that
feed them, provide habitat necessary for the production
of many fish species. Anadromous fish spend their adult
lives in the ocean but must spawn in freshwater. Anadro-
mous fish species in the Chesapeake Bay include striped
bass, blueback herring, alewife, American and hickory
shad,  shortnose sturgeon and Atlantic sturgeon.
Semi-anadromomous fish, such as white and yellow

perch, inhabit tidal tributaries but also require freshwa-
ter to spawn.

While all these species have different habitat require-
ments, all must have access to freshwater spawning
grounds. However, due to dams and other obstacles,
many historical spawning grounds are no longer avail-
able to fish. The fish not only need access to spawning
grounds but require good stream and water quality con-
ditions for the development and survival of eggs and
juvenile fish. Nutrients, chemical contaminants, exces-
sive sediment  and  low dissolved oxygen degrades
spawning and nursery habitat.

* Shallow Water

The shallow water, or littoral zone, provides key habi-
tats for many life stages  of invertebrates, fish and
waterfowl. Shrimp, killifish and juveniles of larger fish
species use submerged aquatic vegetation, tidal marshes
and shallow shoreline margins as nursery areas and for
refuge. Vulnerable, shedding blue crabs find protection
in the SAV beds. Predators, including blue crabs, spot,
striped bass, waterfowl, colonial waterbirds and raptors
forage for food here. Along shorelines, fallen trees and
limbs also give cover to small aquatic animals. Even
unvegetated areas, exposed at low tide, are productive
feeding areas. Microscopic plants cycle nutrients and
are fed upon by crabs and fish.

« Open Water

Striped bass,  bluefish, weakfish,  American shad,
blueback herring, alewife, bay anchovy and Atlantic
menhaden live in the  open, or pelagic, waters of the
Chesapeake Bay. Although unseen by the naked eye, mi-
croscopic plant and animal life, called plankton, float
in the open waters. These tiny organisms form the food
base for many other animals. More than 500,000 win-
tering  ducks,  particularly sea ducks, like scoters,
oldsquaw, and mergansers, depend on open water for
the shellfish, invertebrates and  fish they eat during the
winter months. Open water also supports oysters and
other bottom-dwellers. Oysters and other filter feeders
help maintain water quality by filtering suspended or-
ganic particles out of the water. The oyster reef itself is
a solid structure that  supports other shellfish,  finfish
and crabs.
                                              BAY QUOTE:

           Living Resources  &
           Biological Communities
Within every habitat, communities of organisms exist
in close relationship to each other. Communities may
be as small as an oyster bar or as large as the entire
Bay. The relationships among species form a com-
plex web. Some organisms produce food and
others serve as prey. Some communities, like sub-
merged aquatic vegetation (SAV) provide both
food and cover. Many organisms fit into more
than one of these categories. The functions
within a given community are almost endless,
and the Chesapeake supports countless com-
munities both large and small.

Change is character-
istic of ecological
systems, including
Chesapeake Bay. Ger-
mination of plant
seeds, birth of ani-
mals, growth, local
movement and mi-
gration affects the species composition
of each community as does changes in
water quality, loss of habitat or over-
Some variations, such as seasonal
changes in abundance, follow a pre-
dictable pattern. Every year, waterfowl
migrate to the Bay to spend the winter
feeding in uplands, wetlands and shallow
water areas. Then, each spring, they re-
turn to northern parts of the continent
to breed. After mating each sum-
mer, female blue crabs
migrate to the mouth of
the Bay to spawn, while
the males remain in the
upper and middle Bay.
Anadromous fish, like shad
and herring, spend most
of their lives in the
ocean, but each spring
enter the Bay and mi-
grate into freshwater to
spawn. These are just a few
of the seasonal variations that occur.
                    Sea nettle
              (Chrysaora quinquedrrha)
  Striped bass
(Morone saxatilis)
 American oyster
         Blue crab
     (Callinectes sapidus)
  Some Bay communities are
  prone to rapid population
    fluctuations of one or
     more species. This is
     particularly  true  of
     plankton. Rapid changes
     in plankton diversity and
     abundance may occur
    hourly or daily due to the
     interaction of biological,
      physical and chemical

       Many species exhibit
       long-term patterns in
       population abundance
       and distribution. For
         example, croakers
          suffer high mor-
            talities during
            cold  weather.
       This fish was abun-
       dant in the Bay during
        the late 1930s and
        early  1940s. It is
       believed that rela-
       tively mild winters in
       the late 1930s and
       early 1940s promoted
     the high numbers of
     croakers. Human  in-
     duced pressures can
     affect long term patterns.
    Striped bass declined rap-
     idly in late 1970s and
     through the 1980s due
     to overharvesting and
     subsequent reproduc-
     tive failure.
   Individual species may
   belong to a variety of com-
   munities and use different
   habitats throughout their
  life cycles. Habitats are con-
nected and communities often

overlap. Changes in a particular habitat may not only
affect the communities it supports but other habitats
and communities as well.
 In the Chesapeake, wetlands, SAV beds,
plankton, fish and bottom-dwellers are bio-
logical communities supported by the
Bay's varied habitats. Wetlands are transi-
tional areas between uplands and water.
SAV beds range from mean low tide to a
depth of about 2 meters or where light be-
comes limiting to plant growth, although
some freshwater species thrive up to 3
meters deep. Open water supports the
plankton community, composed mostly of
minute creatures that float and drift with
the movement of the water, and the nek-
ton community, the fish and other swimmers who
move freely throughout the Bay and its tributaries. The
bottom sediments support benthic organisms.

• Wetlands

Wetlands, environments subject to periodic flooding
or prolonged saturation, produce specific plant com-
munities and soil types. The presence of water affects
the types of soils that develop and the  types of plants
and animals that live there. Wetlands are characterized
by hydrophytic vegetation (water-loving plants adapted
to wet soils) and hydric soils (saturated or periodically
flooded soils). There are two broad categories of wet-
lands in the Chesapeake Bay watershed. Wetlands
within the reach of tides are considered tidal. Salinity
in tidal wetlands ranges from fresh to saltwater.
            Nontidal or palustrine wetlands are fresh-
            water areas unaffected by the tides.
            Wetlands receive water by rain, ground-
            water seepage, adjacent streams and, in
            the case of tidal wetlands, tides. Salinity,
            substrate and frequency of flooding de-
            termine the specific plant and animal life
            a wetland can support.
                       Tidal wetlands  are dominated by
                       nonwoody or herbaceous vegetation and
                       subjected to tidal flooding. These wet-
                       lands have a low marsh zone (flooded by
                       every high  tide) and a high marsh zone
           (flooded by extremely  high tides). Plants such as
           smooth cordgrass are found in the low marsh zone of
           brackish and saltwater marshes. The high marsh zone
           may be dominated by saltmeadow cordgrass, black
           needlerush, saltgrass or marsh elder.  Freshwater
           marshes also have low  and high zones. Along the
           water's edge you may find wild rice, arrow arum, pick-
           erel weed and pond lily. In the high zone, cattail and
           big cordgrass may be prevalent.

           Nontidal wetlands frequently contain bulrush, broad-
           leaved cattail, jewel weed, spike rushes and sedges.
           Forested wetlands, often referred to as swamps, may
           have permanent standing water or may be seasonally

           A  Button bush
              (Cephalanthus occidentalis)
           B  Big cordgrass
              (Spartina cynosuroides)
C Narrow-leaved cattail
  (Typha angustifolia)
D Black needlerush
  (juncus roemerianus)
E Saltmeadow cordgrass
  (Spartina patens)
                F Wild rice
                  (Zizania aquatica)
                C Widgeon grass
                  (Ruppia maritima)

                                                                                      A Black willow
                                                                                        (Salix nigra)
                                                                                      B Red maple
                                                                                        (Acer rubrumj
                                                                                      C River birch
                                                                                        (Betula nigra)
                                                                                      D Jewelweed
                                                                                        (Impaliens capensis)
                                                                                      E River bulrush
                                                                                        (Scirpus fluviatilis)
                                                                                      F Broad-leaved cattail
                                                                                        (Typha latifolia)
flooded. Trees commonly found in forested wetlands
include red maple, black gum, river birch, black wil-
low, Atlantic white cedar and bald cypress. Willows,
alders and button bushes are types of shrubs present
in forested wetlands.
       for food and cover. Fish and shellfish, many of which
       are commercially valuable, use wetlands as spawning or
       nursery areas. Thousands of aquatic animals, including
       reptiles, amphibians, worms, insects, snails, mussels and
       tiny crustaceans, thrive in wetlands and are food for
                      other organisms.
Approximately 1.7 million acres of wet-
lands remain in the Chesapeake Bay
watershed, less than half of the wetlands
that were here during colonial times. Of
the remaining wetlands, 12 percent are
tidal and 88 percent are nontidal.
Often viewed as wastelands, wetlands
were drained or filled for farms, resi-
dential developments, commercial
buildings, highways and roads. Over the
past several decades our understanding and apprecia-
tion of wetlands has increased.

Plant diversity, biochemical reactions and hydrology
of these habitats make them extremely productive. Wet-
lands support large quantities of plant biomass. The
huge amount of visible plant material in wetlands makes
up only the above-ground biomass. The below-ground
biomass, composed of root and  rhizome material, is
often more than double the above-ground biomass. This
creates a tremendous reservoir of nutrients and chemi-
cals bound up in plant tissue and sediments.

Many of the Bay's living resources depend on these
wetland habitats for their survival. Tidal wetlands are
the wintering homes for great flocks of migratory wa-
terfowl. Other wildlife, including muskrats, beaver,
otter, song birds and wading birds, rely  on wetlands
                      The abundance of food and shelter pro-
                      vided by wetland vegetation is essential
                      to other members of this community. A
                      host of invertebrates feed on decom-
                      posing plants and  animals.  This
                      nutrient-rich detritus is also available to
                      juvenile stages offish and crabs. A dense
                      layer of microscopic plants and animals,
                      including bacteria and algae, coats the
                      land surface and serves as food. Stems
       of larger plants provide another good source of food.
       Decomposing plants and animals are the major  food
       source for many other wetland inhabitants.

       Wetlands are also important for controlling flood and
       storm waters. Fast moving water is slowed by vegeta-
       tion and temporarily stored in  wetlands. The gradual
       release of water reduces erosion and possible property
       damage.  Coastal wetlands absorb the erosive energy of
       waves, further reducing erosion.

       Poised between land and water, wetlands act as buffers,
       regulating the flow of sediments and nutrients into riv-
       ers and the Bay. As water runs off the land and passes
       through wetlands, it is filtered. Suspended solids, includ-
       ing sediment and pollutants, settle and are trapped by
       vegetation. Nutreints, carried to wetlands by tides, pre-
       cipitation, runoff and groundwater, are trapped and used

 by wetland vegetation. As plant material decomposes,
 nutrients are released back into the Bay and its tributar-
 ies, facilitated by f loodwaters or tides.

 Economically, wetlands provide opportunities for fish-
 ing, crabbing and  hunting. Other popular activities
 include hiking, birdwatching, photography and wild-
 life study. People are lured by the beauty  of wetlands
 and much leisure time is spent simply enjoying the sights
 and sounds these areas can offer.

 » Submerged Aquatic Vegetation

 In the shallow waters of Chesapeake Bay,  underwater
 grasses sway in the aquatic breeze of the current. Known
 as submerged aquatic vegetation or SAV, these amazing
 plant communities provide food and shelter for water-
 fowl, fish, shellfish  and invertebrates. Like other green
 plants, SAV produces oxygen, a precious and sometimes
 lacking commodity in the Chesapeake Bay. These un-
 derwater plants filter and trap sediment that can cloud
 the water and bury bottom-dwelling organisms like oys-
 ters. As waves roll into SAV beds, the movement is slowed
 and energy is dispelled, protecting shorelines from ero-
 sion. During the growing season, SAV takes up and
 retains nitrogen and phosphorus,  removing excess nu-
 trients that could fuel unwanted growth of algae in the
 surrounding waters.

 Like a forest, field, or wetland, an SAV bed also serves as
 habitat for many aquatic animals. Microscopic zooplank-
 Widgeon grass
(Ruppia maritima)
(Zostera marina)
                  ton feed on decaying SAV and, in turn, are food for larger
                  Bay organisms. Minnows dart  between the plants and
                  graze on tiny organisms that grow on the stems and leaves.
                  Small fish seek refuge from larger and hungrier mouths.
                  Shedding blue crabs conceal themselves in the vegetation
                  until their new shells have hardened. Thus, SAV is a key
                  contributor to the energy cycling in the Bay. SAV is a valu-
                  able source of food, especially  for waterfowl. In the fall
                  and winter, migrating waterfowl search the sediment for
                  nutritious seeds, roots and tubers. Resident waterfowl may
                  feed on SAV year-round.

                  There are thirteen species of SAV commonly found in the
                  Bay or nearby rivers. Salinity, water depth and bottom
                  sediment determine where each species can grow. Sur-
                  vival of SAV is affected most by the amount of light that
                  reaches the plants.  Poor water quality resulting in less
                  light penetration is the primary cause for declining SAV.

                  Factors that affect water clarity, therefore, also affect the
                  growth of SAV. Suspended sediment and other solids cloud
                  the water, blocking precious sunlight from the grasses.
                  Excessive amounts of suspended sediment may cover the
                  plants  completely. Sources of suspended sediments  in-
                  clude runoff from farmland, building sites and highway
                  construction. Shoreline erosion also adds sediment to the
                  Bay. Land development, boat traffic and loss of shoreline
                  vegetation can accelerate natural erosion.

                  Nutrients, although vital to all ecosystems, can create prob-
                  lems when present in excessive amounts. Major sources
    Wild celery
(Vallisneria americana)
     Redhead grass
(Potamogeton perfoliatus)

of nutrients include sewage treat-
ment plants, acid rain, agricultural
fields and fertilized lawns. High lev-
els of nutrients stimulate rapid
growth of algae, known as blooms.
Algae blooms cloud the water and
reduce  the amount of sunlight
reaching SAV. Certain types of algae
grow directly on the plants, further
reducing available sunlight.

Historically, more than 200,000
acres of SAV grew along the shore-
line of Chesapeake Bay. By 1978, a
survey of SAV  documented only
41,000 acres. Declining water qual-
ity, disturbance of SAV beds and
alteration of shallow water habitat
all contributed to the Bay-wide de-
cline. The absence of SAV translates
into a loss of food and habitat for
many Chesapeake Bay species.

Water quality is the key to restoring
grasses to the Bay. Scientists have
identified the water quality condi-
tions and requirements necessary
for the survival of five SAV species
from wild celery found in freshwa-
ter, to sago pondweed, redhead
grass and widgeon grass found in
more estuarine  water and eelgrass
found in the lower Bay in saltier wa-
ter. Each species is an important
source of food for waterfowl. SAV
is making a comeback. Water qual-
ity is beginning to improve  due to
the ban of phosphates in detergents,
reduction of fertilizer use by farm-
ers and homeowners, protection of
shallow water habitat and the reduc-
tion of nutrients in sewage effluent.
In 1984 only 38,000 acres  of SAV
were reported  in the Bay and its
tidal tributaries. By 1993 more than
73,000 acres of SAV were reported,
representing an 85 percent increase
from the low 9 years earlier.

 *  Plankton

Mainly unseen by the naked eye, a
community made up of predomi-
nantly microscopic organisms also fuels the ecosystem
we call the Chesapeake Bay. These tiny plants and ani-
mals, called plankton, drift with  the water largely at
the mercy of the currents and tides. Some of the tiny
creatures move up and
down in the water col-
umn to take advantage of
light. Others will drop be-
low  the pycnocline, an
intermediate layer where
the increase in salinity is
more pronounced,  to
avoid being washed out to
the ocean.

Phytoplankton are tiny single-celled plants. Like higher
plants, phytoplankton require light to live and reproduce.
Therefore, the largest concentrations occur near the sur-
face. Salinity affects phytoplankton distribution with the
largest number of species preferring the saltier waters
near the mouth of the Bay. The amount of nutrients in
the water is a major determinant  in the  abundance of
these plants. The largest concentrations of phytoplank-
ton in the Bay occur during the spring when nutrients
are replenished by freshwater runoff from the watershed.
These high concentrations produce the characteristic
brown-green  color of estuarine and near-shore waters.
Although there are many species of phytoplankton, the
major   types   in  the  Bay  are  diatoms   and
dinoflagellates.When dinoflagellates dominate the wa-
ter,  a red-tinted bloom, called a mahogany tide, is
produced. Mahogany tides typically occur on warm, calm
days often following rain. Diatoms, which are present
throughout much of the year, may account for 50 per-
cent of total algal production.

Changes in chemical conditions, such as the addition of
nutrients, can cause rapid increases in the numbers of
algae. These algal blooms can have serious consequences.
They block light from reaching SAV beds. Even after they
die, they can cause problems. Deposition and subsequent
decomposition of large masses of plankton in the
mainstem of the Bay can deplete dissolved oxygen, suf-
focating other estuarine  animals.

Phytoplankton are the major food source for microscopic
animals called zooplankton. Dominating the zooplank-
ton are the copepods, a group of tiny crustaceans, about
one  millimeter long, and fish larvae. Zooplankton are
distributed according to  salinity levels. Distribution pat-
terns are also related to those of their main food source,
the phytoplankton. Zooplankton also feed on other par-
ticulate plant matter and bacteria.

The tiny larvae of invertebrates and fish are also consid-
ered zooplankton. Although this planktonic stage is only
temporary, the larvae are a significant part of the com-
munity. These larvae are consumed by larger animals,
and may, as they grow, consume copepods.

Another group of zooplankton found in the Bay are the
protozoa. These single-celled animals feed on detritus
and bacteria. They, in turn, become food for larvae, cope-
pods and larger protozoa.

Bacteria play an important role in the Bay. They are es-
sentially the decomposers. Their primary function is to
break down dead matter. Through this process, nutri-
ents in dead  plant  and animal matter again become
available for growing plants. Bacteria are eaten by zoo-
plankton and other filter feeding animals in the Bay.

Bacteria  can  be residents of the Bay or introduced
through various pathways, including human sewage and
runoff from the land. Coliform bacteria are normal resi-
dent bacteria found in the intestines of mammals. The
presence of coliform in a body of •water indicates that
human or other animal wastes  are present. Coliform
bacteria are an indicator that disease-producing patho-
gens may be present in the water.

Clearly visible to the unaided eye, jellyfishes and comb
jellies are the largest zooplankton. Some of these gelati-
                  Bay anchovy
                (Anchoa mitchilli)
nous creatures swim, though they are still at the mercy
of the water currents. Jellyfishes have tentacles with
stinging cells used to stun prey. The most famous jelly-
fish in the Chesapeake is the sea nettle. Sea nettles feed
voraciously on other zooplankton, including fish larvae,
comb jellies, and even small fish. Because of the large
volume of water in their bodies, few animals, except
sea turtles, prey on sea nettles. Comb jellies, lacking
the stinging cells of nettles, capture prey with adhesive
cells. They too consume vast quantities of small cope-
pods and zooplankton, especially oyster larvae.

*  The Swimmers

Swimmers comprise the nekton community. These or-
ganisms can control and direct their movements. This
group includes fish and some crustaceans and other in-
vertebrates. Approximately 250 species of fish can be
found in the Chesapeake Bay. They can be divided into
permanent residents and migratory fish. The residents
tend to be smaller in size and do not travel the huge
distances that migratory species do.

Smaller resident species, like killifish, normally occur
in shallow water where they feed on a variety of inver-
tebrates. The bay anchovy, the most abundant fish in
the Bay, is a key player in the Chesapeake food web. Bay
anchovies feed primarily upon zooplankton. Adult an-
                                          (Cynosdon regalis)
     Striped killifish
    (Fundulus majalls)
                              (Pomatomus saltatrix)
                                                                      Striped bass
                                                                    (Morone saxatitis)

chovies may also consume larval fish, crab lar-
vae and some benthic species. In turn, the
bay anchovy is a major food source for preda-
tory fish  like striped bass, bluefish and
weakfish, as well as, some birds and mammals.
Migratory fish fall into two categories; anadro-
mous, which  spawn in the Bay or its
tributaries,  and catadromous fish, which
spawn in the ocean. Anadromous fish migrate
varying distances to spawn in freshwater.
Some can even be considered Bay residents. For instance,
during the spawning season, yellow and white perch travel
short distances from the brackish water of the middle Bay
to freshwater areas of the upper Bay or tributaries. Striped
bass also spawn hi the tidal freshwater areas  of the Bay
and major tributaries. Some remain in the Chesapeake to
feed while others migrate to ocean waters. Shad and her-
            The blue crab is difficult to place in any
            one community, needing  a variety  of
            aquatic habitats, from the mouth of the
            Bay to fresher rivers and creeks, in order
            to complete its life cycle. Throughout the
            year crabs may burrow into the Bay bot-
            tom, shed and mate in shallow waters and
            beds of submerged aquatic vegetation or
            swim freely in open water.  The first life
            stage of a blue crab, called the zoea, is
            microscopic and lives a planktonic free-
floating existence. After several molts, the zoea reaches
its second larval stage: the megalops. Another molt and
a tiny crab form is apparent.  Both juvenile and adult
blue crabs forage on the bottom and hibernate there
through the winter. In spring, the crab quickly begins
migrating from the southern part of the Chesapeake to
tidal rivers and northern portions of the Bay. During the
                                         LIFE STAGES OF A BLUE CRAB
ring are truly anadromous, traveling from the ocean to
freshwater to spawn and returning to the ocean to feed.
Eels are the only catadromous species in the Chesapeake
Bay. Although they live  in the Chesapeake Bay for long
periods, eels eventually migrate to ocean waters in the
Sargasso Sea to spawn.

Other fish utilize the Bay strictly for feeding. Some, like
croaker, drum, menhaden, weakfish and spot, journey into
the Bay while still in their larval stage to take advantage of
the rich supply of food. The abundance of menhaden sup-
ports a commercial fishing industry and provides food for
predatory fish and birds. Bluefish enter the Bay only as
young adults or mature fish.

Besides fish, crustaceans and invertebrates, like shrimp,
crabs and worms, may be part of the nekton community.
Larger animals  like sharks, rays, sea turtles  and occas-
sionally dolphins and whales enter the Bay.
       rest of the year, adult blue crabs are dispersed through-
       out the Bay, swimming considerable distances using
       their powerful paddle-like back fins.

       » Life at the Bottom

       The organisms that live on and in the bottom sediments
       of the Bay  form complex communities. Known as
       benthos, these bottom-dwellers include animals, plants
       and bacteria. Benthic organisms are often differentiated
       by their habitat. Epifauna, like oysters, barnacles  and
       sponges, live upon a surface. Worms and clams, consid-
       ered infauna, form their own community structure
       beneath the bottom sediments, connected to the water
       by tubes and tunnels.  The roots and lower portions of
       submerged aquatic vegetation supply the physical sup-
       port for a wide variety of epiphytic organisms. An oyster
       bar, and the many species it supports, is another ex-
       ample of a benthic community. Benthic communities

                                               BENTHIC COMMUNITY
A  Hard clam (Mercenaria mercenaria)
B  Atlantic oyster drill (Urosalpinx cinerea)
C  Common clam worm (Nereis sucdnea)
D  Red ribbon worm (Micrura leidyi)
E  Soft-shelled clam (Mya arenaria)
F Classy tubeworm (Spiochaetopterus oculatus)
C Black-fingered mud crab (Panopeus herbstii)
H Whip mudworms (Polydora ligni)
I  Sea squirts (Molgula manhattensis)
]   Oyster spat
K  Ivory barnacle (Balanus eburneus)
L  Skilletfish (Cobiesox strumosus)
M American oyster (Crassostrea virginica)
     that exist on or in bare, unvegetated substrates are made
     up of molluscs, worms and crustaceans.

     As with all aquatic life in the Bay, salinity affects the
     distribution of bottom-dwellers but sediment type also
     plays a role. Neither coarse sand nor soft mud support
     rich benthic populations. The best sediment for diverse
     benthic communities consists of a mixture of sand, silt
     and clay. Some organisms require specialized substrates.
     Oysters need a clean hard surface, preferably another
     oyster shell, on which the larval spat can attach or set.
     Oysters form a reef community that is important habi-
     tat for other benthic species.

     The benthic community affects the physical and chemi-
     cal  condition of the water and sediments. Some build
     tubes or burrows through which they pump water. In-
     faunal deposit feeders, such as worms, plow through
     the sediments in search of food. Many benthic animals
     bind sediments together as fecal pellets that remain at
     the bottom. Predators, such as adult blue crabs,  scurry
     across the bottom searching for food. These activities
     stir the  sediments, increasing the rate  of exchange  of
     materials into the water column. This  mixing also in-
     creases diffusion of oxygen into the sediments.
                     Filter feeders, like oysters and clams, pump large vol-
                     umes of water through their bodies and extract food
                     from it. As they filter water for food, they also remove
                     sediments and organic matter, cleaning the water. Since
                     many toxic substances are often present in sediments,
                     benthic fauna are often exposed to and can be harmed
                     by these pollutants.

                     Some benthic organisms, such as blue crabs, are widely
                     distributed. Others are limited more by salinity. For ex-
                     ample, hard  clams and oysters  require higher saline
                     waters. Mid-salinity waters support soft-shelled clams.
                     Brackish water clams are also found in lower salinities,
                     along with freshwater mussels. Salinity also determines
                     the distribution of certain benthic predators, parasites
                     and diseases. MSX, a lethal parasite, and Dermo, a dis-
                     ease caused by another parasite, have decimated oyster
                     populations of the mid and lower Bay, respectively. Oys-
                     ter drills and starfish, which feed on oysters, are less of
                     a problem in upper Bay waters because of their intoler-
                     ance to low salinities.

             Food Production
             & Consumption
The most important relationship among Bay species is
their dependence upon each other as food. We are all
carbon-based creatures. Carbon is the basic element of
all organic compounds such as proteins, carbohydrates,
lipids and nucleic acids. These compounds are the build-
ing  blocks of life that make up the bodies of living
organisms.  Feeding is the process by which organisms
cycle energy-rich carbon through the ecosystem. Each or-
ganism supplies the fuel needed to sustain other life forms.
                             BAY FACT:

Plants and some bacteria can produce their own food
through a process known as photosynthesis. Using en-
ergy from the sun, carbon dioxide and water are combined
to form high-energy organic compounds. These organic
compounds and other necessary chemicals form a plant's
cellular structure, allowing it to grow. Because of this abil-
ity to use carbon dioxide and sunlight to produce their
own food, plants are called autotrophs, or self-feeders.
They are the primary food producers. All other organ-
isms must feed, directly or indirectly, on organic material
produced by plants.

Animals cannot process carbon via photosynthesis. In-
stead, they acquire carbon by eating the organic matter
contained in plant and ani-
mal tissue or dissolved in
water. The animal breaks
this organic material down
into components it can use
for energy and growth.
Animals are heterotrophs,
or other-feeders.
Every biological activity,
such as reproduction,
growth, movement and bodily functions, requires energy.
Whether organisms produce food themselves or ingest
it from other sources, they all must break down organic
molecules to use  the carbon and energy contained
within. This process is called respiration.

Aerobic respiration uses oxygen and releases carbon in
the form of carbon dioxide. It complements photosyn-
thesis, which uses carbon dioxide and produces oxygen.
Together, aerobic respiration and photosynthesis com-
pose the carbon-oxygen cycle.

All living things respire, but autotrophs carry out photo-
synthesis as well. Plants usually release more oxygen than
they consume and animals use that excess oxygen for
respiration.  In turn, animals release  carbon dioxide,
which plants require for photosynthesis.

While carbon and oxygen are two of the most prevalent
elements in our physical  make-up, many others are
needed. Nitrogen and phosphorus are two such elements.
They are crucial to the operation of the Bay's life sup-
port system.

Nitrogen is a major component of all organisms, prima-
rily as a key ingredient in protein. When an organism
dies, bacteria breaks down proteins into amino acids.
Bacteria then remove the carbon, converting the acids
into ammonia. Plants are able to use ammonia as a source
of nitrogen. In the presence of oxygen, other bacteria
convert ammonia to nitrite and nitrate, also good nitro-
gen sources for plants. Under low oxygen conditions,
some bacteria convert nitrate to gaseous nitrogen which
is unavailable to most aquatic organisms. However, in tidal
freshwater, some blue-green algae are able to use gas-
eous nitrogen directly.

                         FOOD CHAIN
                    Decomposers &
                    Detritus Feeders
Phosphorus is another element essential to plant growth.
During decomposition and in the presence of oxygen,
bacteria convert organic phosphorus to phosphate. Phos-
phates are readily used by plants. However, phosphate
also attaches to sediment particles and settles out of wa-
ter very quickly. The resulting decrease  in available
phosphorus can limit plant growth.
Temperature, sunlight, carbon dioxide and usable ni-
trogen and phosphorus control the rate of photo-
synthesis. Since plants are the only organisms able to
produce new food from inorganic matter, the rate of
photosynthesis determines the production of organic
carbon compounds and, ultimately, the availability of
food in the Chesapeake Bay ecosystem.

To illustrate how these factors affect the productivity
of the Bay, lets look at the Chesapeake's most abundant
food producer, the phytoplankton. like all plants, phy-
toplankton require sunlight, nutrients and water. In the
Bay, water is never a limiting factor. However, the
amount of sunlight and nutrients can limit phytoplank-
ton growth. The  amount of sunlight available to an
aquatic plant depends on the sun's altitude, cloud cover,
water depth and turbidity (cloudiness of water). Tem-
perature also controls the rate of photosynthesis.

Nutrients in the form of carbon and usable nitrogen and
phosphorus are rarely available in the exact proportions
required by plants. Normally, one nutrient is in short
supply compared  to the others and is considered the
limiting nutrient. If a limiting nutrient is added,  a growth
spurt may occur. Conversely,  reducing the amount of a
limiting nutrient causes plant production to decline.

Phosphorus controls the growth of some phytoplank-
ton species in the spring, especially in the tidal
freshwater  and brackish areas. Nitrogen is the prime
limiting factor at higher salinities, particularly during
warm months. Carbon dioxide limitations may control
the rate of photosynthesis during algal blooms in tidal

The Bay's life support system depends on maintaining
the delicate balance between the living and non-living
components. Although the Chesapeake's potential pro-
duction capacity is massive, it is also  finite. Problems
affecting the simplest producers dramatically affect the
survival of consumers.

* The Food Web

As one organism eats another, a food chain is formed.
Each step along a food chain is known as a trophic level
and every organism can be categorized by its feeding or
trophic level. The most basic trophic level is made up of
producers, plants and algae which make their own food.
Organisms that eat plants or other animals are consum-
ers. Decomposers digest the bodies  of dead plants and
animals and the waste products of both. An example of
a simple food chain starts with phytoplankton convert-

ing sunlight and nutrients into living tissue. They are,
in turn, eaten by copepods, members of the zooplank-
ton community. The copepods are then consumed by
bay anchovies, which are eaten by bluefish and striped
bass. These fish can be harvested and eaten by people.
This illustrates how organic carbon compounds origi-
nally produced by a  plant, are transferred to higher
trophic levels.

Food production and consumption in the Chesapeake
Bay is rarely this simple or direct. Seldom does one or-
ganism feed exclusively on another. Usually, several food
chains are interwoven together to form a food web. De-
composers  appear throughout the food web, breaking
organic matter down into nutrients. These nutrients are
again available to producers. This complex network of
feeding continuously cycles organic matter back into the

The transfer of energy from one organism to the next is,
however, inefficient. Only about 10 percent of the avail-
able energy is transferred from one trophic level to the
next. For example, only a portion of the total amount of
phytoplankton carbon ingested by zooplankton is assimi-
lated by the zooplankton's digestive system. Some of that
is used for respiration, bodily functions and locomotion.
A small fraction is used for growth and reproduction.
Since these are the only functions that produce addi-
tional tissue, only this fraction of energy is available to
the consumer at the next trophic level.

Economically-important foods like
fish and shellfish depend upon
lower trophic level organisms. For
every  pound of commercial fish
taken  from the Chesapeake, al-
most 8,000 pounds of plankton
had to be produced. An ecosystem
must be  extremely productive to
support large populations of organ-
isms at the highest trophic levels.
Massive  quantities  of plants are
required to support carnivores, such
as striped bass or bluefish. Because
producers are the basis of all food,
they influence the production of
other organisms. However, an overabundance of cer-
tain producers, like algae, can also be detrimental,
causing a loss of  SAV and reducing the amount  of
dissolved oxygen available to other organisms.

Toxic  substances in contaminated prey can also
be passed on to the consumer. Heavy metals and
organic chemicals are stored in the fatty tissues of ani-
mals and concentrate there. As a result, an animal's body
may contain a much higher concentration of the con-
taminant than did its food. This phenomenon is known
as bioaccumulation. The severe decline of the bald eagle
during  the 1950s and  1960s  was  attributed  to
bioaccumulation. During World War II, a chemical pes-
ticide, DDT, was used to control insects and agricultural
pests. Fish and small mammals that fed on these pests
were in turn contaminated with higher concentrations.
Eagles eating contaminated prey concentrated even
higher levels of DDT and its by-product, DDE. The DDE
caused the birds to lay eggs with extremely thin shells,
so thin that most eggs broke in the nest and many eagle
pairs failed to produce young. Only after banning the
use of this chemical were bald eagles able to recover to
the population we have today.
 » Direct and Detrital Pathways

Two basic pathways dominate the estua-
rine food web. The direct pathway leads
from plants to lower animals to higher
animals.  v The detrital pathway leads
                              A Harpacticoid
                                (Scottolana canadensis)
                              B Calanoid
                                (Acartia clausi)
                              C Cyclopoid
                                (Oithona colcarva)

from dead organic matter to lower animals then to higher
animals. The detrital pathway is dominant in wetlands
and submerged aquatic vegetation beds.
The direct and detrital pathways coexist
and are not easily separated. Higher plants,
like eelgrass, widgeon grass, saltmarsh
grass and cordgrass contribute most of their
carbon as detritus. However, epiphytic al-
gae growing on these grasses is usually
eaten by consumers, putting them in the
direct food web.
hi deeper waters, detritus from dead phy-
toplankton, zooplankton and larger animals, as well as
detritus from upland drainage, wetlands and submerged
aquatic vegetation, continually rains down on the Bay
floor. Bottom-dwelling animals such as oysters, clams,
crustaceans, tube worms, shrimp and blue crabs feed
on it.

The direct pathway dominates the plankton community.
The smallest of phytoplankton, known as nannoplank-
ton,  are fed upon by larger microzooplankton. Larger
phytoplankton, like most diatoms and dinoflagellates,
provide food for larger zooplankton and some fish. Bac-
teria, fungi, phytoplankton and  possibly protozoa
provide food for oysters and clams.

Copepods, a dominant form of zooplankton, play a key
role in the food web between phytoplankton and ani-
mals. Copepods feed on most phytoplankton species and
                                              BAY FACT
occasionally on the juvenile stages of smaller copepods.
In marine waters, most animal protein production from
            plant material is carried out by copepods.
            Copepods and a related organism, krill, are
            the world's largest stock of living animal
            protein. Larger carnivores feed voraciously
            on them. Herring, for example, may con-
            sume thousands of the tiny creatures  in a
            single day.
            Most of the Bay's fish are part of the direct
            food web but their feeding habits are com-
            plex. Some experts contend that menhaden
            are the dominant fish in the Bay's intricate
food web. The extremely fine gill rakers of menhaden
act as a filtering net. Adult menhaden swim with their
mouths open, consuming any plankton in their paths. In
turn, menhaden are a major food of striped bass, bluefish
and osprey. They also support a large commercial fishery
that utilizes the fish for animal feed and other products
containing fish meal and oil.

Like menhaden, anchovies and all fish larvae are prima-
rily zooplankton feeders. Adult striped bass, bluefish and
weakfish feed mainly on other fish. Striped bass and other
predators may also feed upon young of their own spe-
cies.  Many fish are omnivorous, eating both plants and
animals. Omnivores, like eels and croakers, feed on plank-
tonic copepods, amphipods, crabs, shrimp, small bivalves
and small forage fish. Small forage fish, like killifish and
silversides, often feed upon the epifauna and epiphytes
along wetlands and in shallow water communities.

             Preserving Chesapeake
             Bay: the  Bis. Picture
            	+s	^^	
If we want to preserve the Chesapeake Bay and its many
delights for future generations, we must change our per-
spectives. We must view not only what is
occurring in the Bay itself but on the land
surrounding it. It is not enough to protect
shorelines, regulate fisheries and prevent
direct disposal of pollutants. We must take
into account all the activities that occur
throughout the watershed from Coopers-
town, New York to Virginia Beach,
Virginia, and from Pendleton County, West
Virginia to Seaford, Delaware. Released into
this watershed, fertilizers from farms, sedi-
ment from residential developments, and
toxic compounds travel in a single direc-
tion, downstream to the Chesapeake Bay.

However, even a watershed perspective is not adequate
without personal responsibitlity. Even though we ac-
knowledge that activities in the watershed affect the Bay
ecosystem, we must also realize that  individual actions
impact the Bay everyday. Fertilizers and pesticides from
yards and gardens affect the Bay as much as those from
large farms. Excessive use of cars requires more roads,
          decreasing vegetated areas that could in-
          tercept runoff. Indiscriminate use of water
          results in more water that must be treated
          and then discharged into the Bay.
                   If we want a clean, healthy Bay that can
                   sustain the biological diversity and be eco-
                   nomically stable, we must identify, alter
                   and, if possible, eliminate our own indi-
                   vidual actions that impact the Bay. People
                   alter ecosystems. The solutions to prob-
                   lems threatening the Chesapeake Bay lie
                   in the life-styles we choose. The Chesa-
                   peake Bay ecosystem is one unit where
          forests are linked to oyster reefs, housing developments
          to SAV, and choices to responsibility. Education is also
          required. Informed people choose actions that are ben-
          eficial for themselves, their culture, their community
          and the Chesapeake Bay.

* Be Part of the Solution,
  Not Part of the Problem

1.  Reduce your nutrient input to the Bay.
   Start a compost pile instead of using a garbage dis-
   posal. Limit the amount of fertilizers spread on
   gardens and lawns. Plant native vegetation that re-
   quires less fertilizing and watering. Leave grass
   cUppings on lawns and gardens, instead of fertiliz-
   ing. If you have a septic system, make sure it is
   functioning properly.

2.  Reduce the use of toxic materials
   around your house and yard.
   Use cleaning agents made from natural substances.
   Talk to a Cooperative Extension Agent to find natu-
   ral pest controls and alternatives to herbicides.

3.  Reduce erosion.
   Plant strips of vegetation along streams and shore-
   lines. Divert runoff from paved surfaces to vegetated
                  4. Save water.
                     Use water-saving devices in toilets and sinks. Turn
                     off water when not in use. Wash cars in grassy areas
                     to soak up soapy water.

                  5. Drive less.
                     Join a carpool or use public transportation.

                  6. Obey all fishing, hunting
                     and harvesting regulations.

                  7. Be a responsible boater.
                     Avoid disturbing shallow water areas and submerged
                     aquatic vegetation beds. Pump out boat waste to an
                     onshore facility

                  8. Get involved.
                     Join a citizens' environmental advocacy group or start
                     your own. Talk to your city, town or county elected
                     officials about your concerns. Join or start a water-
                     shed association to monitor growth and development
                     locally. Participate in citizen monitoring and clean-
                     up activities.
                                  For more information about
                                  the Chesapeake Bay contact:
Maryland Chesapeake Bay
Communications Office
State House
Annapolis, MD 21401
(410) 974-5300

D.C. Department of Consumer
and Regulatory Affairs
Environmental Regulation
2100 Martin Luther King Jr.
Avenue, S.E., Suite 203
Washington, D.C. 20020

Pennsylvania Bay Education
225 Pine Street
Harrisburg, PA 17101
(717) 236-1006

Virginia Department of
Environmental Quality
P.O. Box 10009
Richmond, VA 23240
(804) 762-4440
Alliance for the Chesapeake Bay
Chesapeake Regional
Information Service
1-800 662-CRIS

Other Alliance Offices:
6600 York Road, Suite 100
Baltimore, MD 21212

P.O. Box 1981
Richmond, VA 23216

225 Pine Street
Harrisburg, PA 17101
(717) 236-8825

Save Our Streams
258 Scotts Manor Drive
Glen Burnie, MD 21601

Chesapeake Bay Foundation
162 Prince George Street
Annapolis, MD 21401
U.S. Environmental Protection Agency
Chesapeake Bay Program Office
410 Severn Avenue, Suite 109
Annapolis, MD 21403
(410) 267-5700
1-800 YOUR BAY

National Oceanic and
Atmospheric Administration
Chesapeake Bay Office
410 Severn Avenue, Suite 107
Annapolis, MD 21403

U.S. Fish and Wildlife Service
Chesapeake Bay Field Office
177 Admiral Cochrane Drive
Annapolis, MD 21401

                The Chesapeake Bay Program - Leading the Restoration
The Chesapeake Bay Program is the unique regional part-
nership which has been directing and conducting the
restoration of Chesapeake Bay since the signing of the his-
toric 1983 Chesapeake Bay Agreement. The Chesapeake
Bay Program partners include the states of Maryland, Penn-
sylvania, and  Virginia;  the District of Columbia; the
Chesapeake Bay Commission, a tri-state legislative body;
the Environmental Protection Agency, representing the fed-
eral agencies; and participating advisory groups.

As the largest estuary in  the United States and one of the
most productive in the world, the Chesapeake was this
nation's first estuary targeted for restoration and protec-
tion. In the late 1970's scientific and estuarine research on
the Bay pinpointed three areas requiring immediate atten-
tion: nutrient over-enrichment; dwindling underwater Bay
grasses; and toxic pollution. Once the initial research was
completed, the Chesapeake Bay Program evolved as the
means to restore this exceptionally valuable resource.

Since its inception, the Chesapeake Bay Program's highest
priority has been the restoration of the Bay's living re-
sources - its finfish, shellfish and  other aquatic life and
wildlife. Recent years brought significant progress in the
Bay restoration effort. Improvements have been achieved
in several areas including habitat restoration, nutrient re-
duction, and  estuarine  science. Examples of specific
actions initiated by the Chesapeake Bay Program include a
watershed-wide phosphate detergent ban, the introduction
of agricultural  best management practices, biological nu-
trient removal, and a public education campaign
emphasizing the role each of the watershed's 15 million
residents play in the restoration.

Considered a national and international model for estua-
rine research and restoration programs, the Chesapeake
Bay Program is still a "work in progress". Since 1983, mile-
stones in the evolution of the Chesapeake Bay Program
include  the signing of the 1987 Chesapeake Bay Agree-
ment, the 1992 Amendments to the Chesapeake Bay
Agreement, and the 1993 and 1994 Directives by the
Chesapeake Executive Council -- the policy-making body
of the Chesapeake Bay Program.

In the 1987 Agreement, the Chesapeake Bay Program part-
ners set a goal to reduce the nutrients nitrogen and
phosphorous entering the Bay by 40% by the year 2000.
Achieving a 40% nutrient reduction will ultimately improve
the oxygen levels in Bay waters and encourage aquatic life
to flourish.
hi the 1992 Amendments, the partners agreed to maintain
the 40% goal beyond the year 2000 and attack nutrients at
their source -- upstream in the Bay's tributaries. In Novem-
ber 1992, the Chesapeake Bay Program established
watershed-wide nutrient reduction targets for the Bay's 10
major tributaries. As a result, Pennsylvania, Maryland, Vir-
ginia, and the District of Columbia are developing "tributary
strategies" to achieve the nutrient  reduction targets.  The
Chesapeake Bay Program also began  reevaluating its
Basinwide Toxics Reduction Strategy in order to better un-
derstand the impact toxics have on the Bay's resources.

hi 1993, the Chesapeake Bay Program partners celebrated a
"Decade  of Progress" by highlighting the 10th anniversary
of the signing of the original Bay Agreement along with some
of the restoration successes to date, including an increase in
the acreage of underwater Bay grasses, record-setting num-
bers of young rockfish, and significant reductions of point
source pollution. The partners also  acknowledged that the
Chesapeake Bay Program made a significant transition since
1983, moving from the research phase to the implementa-
tion phase.

Highlighting the results-oriented emphasis of the Chesapeake
Bay Program, the Executive Council guided the restoration
effort in 1993 with five directives addressing key areas of
the restoration, including the tributaries, toxics, underwa-
ter bay grasses, fish passages, and agricultural nonpoint
source pollution. Specifically, the Executive Council directed
the partners to outline initiatives for nutrient reduction in
the Bay's tributaries; revise the Basinwide Toxics Reduction
Strategy by 1994; develop action plans to  address problems
related to toxics in specific geographic areas within the wa-
tershed;  and work with the agricultural community to
implement total resource management programs on farms
in the watershed.

In addition, the Executive Council set an  initial goal for re-
covery of Bay grasses at 114,000 acres by the year 2005; and
set five- and 10-year goals for reopening 582 and 1,350 river
miles of spawning habitat by the removal of blockages, such
as small dams, on the Bay's tributaries which prevent migra-
tory fish  from reaching spawning areas.

hi 1994,  the Executive Council called the implementation
of the tributary strategies the top priority for the Chesapeake
Bay and its tributaries. The Executive Council also adopted
the 1994 Chesapeake Bay Basinwide Toxics Reduction and
Prevention Strategy. In addition, the Executive Council is-
sued new initiatives for riparian forest buffers,  habitat
restoration, and agricultural certification programs.

Striped Bass
                                                 Potamogeton perfoliatus