The mixing of freshwater with saltwater from the Atlantic Ocean in the Chesapeake Bay creates the nation's largest estuary, home to more than 3,700 species of plants and animals. Estuaries are highly productive environments because they provide a variety of habitats, which in turn support a great diversity of life.
About half of the Chesapeake's water volume comes from the saltwater of the Atlantic Ocean. The other half comes from freshwater rivers and streams that drain into the Bay from its 64,000-square-mile watershed. The Chesapeake estuary, the surrounding watershed, and the variety of organisms that live in this environment make up the Chesapeake ecosystem. All elements of this ecosystem interact with each other in some way, depending directly or indirectly on each other for survival.
We can see this interconnectedness in the decline of some of the important species that live in the Chesapeake ecosystem. Although a combination of natural and human factors may be responsible for the decline, the most common cause is the loss of habitat.
In the following sections, explore the key habitats of the Chesapeake Bay ecosystem and some of the challenges they face.
Healthy habitats are the key to healthy plants and animals. Each species has particular habitat needs that must be met for survival. There are six types of habitats in the Chesapeake Bay watershed. Explore them below.
A forest is an area that is mainly covered by woody plants and trees.
Forests are critical to the health of the Chesapeake Bay. Large areas of trees perform important ecological functions such as cleaning our water and air.
Forests provide clean water:
- Forests are like giant sponges, trapping pollutants and nutrients from flowing into our rivers and streams
- Streamside forests, also known as riparian buffers, can reduce the amount of nutrients running into waterways by as much as 30% to 90%
- Forests currently buffer about 60% of the streams and rivers that flow into the Bay
- Mature trees have deep root systems that hold soil in place, helping to stabilize streambanks and reduce erosion
Forests protect clean air:
- Through a process known as attenuation, tree roots, leaves, and forest soils can absorb and trap pollutants in the air
- Forests can capture more than 85% of the nitrogen that falls on them from the air, keeping it from running into our waterways
- Excess nitrogen in our water can fuel the growth of algae blooms, which block light from reaching submerged aquatic vegetation and decrease oxygen levels. Low or no oxygen creates "dead zones" where marine life cannot survive
- Most importantly, trees produce the oxygen we breathe
Forests create habitat:
- Forests provide food, shelter, nesting sites, and safe migration paths for critters in the water and on land
- "Interior" forests, or those that are not near any forest edge or other land use provide dwelling spaces with moderate temperatures and light levels
- Only 40% of Chesapeake forests are considered interior habitat
- Streamside forests shade the waters that run beneath their leafy canopies, maintaining cooler water temperatures and reducing stress on sensitive fish
- The leaves and other plant materials that fall into the water create a nice habitat for underwater critters
- Standing dead trees provide habitat to owls, woodpeckers, squirrels, and other animals that nest in tree cavities
- Many insects, small mammals, and birds can be found foraging and living among the decomposing logs, stumps, and leaves on the forest floor
Rivers & Streams
Streams and rivers not only provide the Chesapeake Bay with its fresh water, they also provide many aquatic species with a critical habitat. Fish, invertebratesm amphibians, and other wildlife species all depend on the Bay's tributaries for survival.
When the Chesapeake's streams and rivers are in poor health, so is the Bay, and the wide array of wildlife it harbors is put in danger.
There are hundreds of thousands of streams, creeks, and rivers throughout the Chesapeake Bay watershed that eventually flow to the Bay. These freshwater tributaries provide critical habitat for many plants and animals.
Fish that spend their entire lives in freshwater:
- Brook trout
Fish that travel from the Bay to the ocean to freshwater streams to spawn:
- Atlantic sturgeon
- Striped Bass
Fish are not the only creatures that live in rivers and streams. There are many invertebrates such as worms, clams, and other shellfish. There are also many plant and amphibian species.
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Aquatic Reefs & Pilings
Aquatic reefs are complex and diverse communities made up of densely packed oysters
Hundreds of aquatic animals find food and shelter in oyster reefs. They have many nooks and crannies that provide a safe haven for small fish and invertebrates to hide from predators
Larger species, including white perch, striped bass, and blue crabs, visit reefs to breed and find food
Reefs are the largest source of hard surface on the Bay's bottom, which is usually covered with soft sediment
The other hard surfaces in the Bay are piers, rocks, jetties, and pilings
Beaches & Tidal Flats
Sandy beaches and tidal mud flats line thousands of miles of Chesapeake Bay shoreline
Beaches are harsh environments where wildlife are subject to wind, waves, and heat
Beaches and tidal flats support a wide variety of plants and animals, including birds, mammals, insects, and invertebrates
Sandpipers and small crabs scurry along the water's edge
Gulls and terns fly above
Underneath the sand and mud, worms, clams, and crabs burrow to avoid predators
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Marshes & Wetlands
Wetlands are transitional areas between land and water
Marshes are a type of tidal wetland along the shoreline where aquatic grasses and sedges grow
Hundreds of species of fish, birds, mammals, reptiles, and invertebrates depend on marshes and wetlands for food
Thousands of aquatic species-- including worms, periwinkles, insects and ribbed mussels thrive in wetlands
In turn, larger animals eat these smaller species
Marshes and wetlands provide shelter for a variety of animals
2/3 of the nations commercial fish and shellfish depend on wetlands as nursery or spawning areas
Large flocks of waterfowl visit wetlands during their winter migrations to feed and rest
Mammals such as muskrats and beavers build their homes in wetlands
Open & Shallow Waters
Along the shores of the Chesapeake Bay is an area of incredible biological activity: the shallows
Many small fish seek refuge from predators in shallow waters
Bay grass beds are a critically important part of the shallows
Provide a haven for migratory fish such as blue fish, cobia, and mackerels
Microscopic plankton float through open waters, forming the base of the Bay's food web
In summer, both the shallows and open waters become very warm, making them susceptible to algae blooms
In winter, animals that dwell in the shallows generally retreate to deeper, warmer waters
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