Wetlands They have characteristics of both land and aquatic habitats and include tidal saltwater marshes, freshwater marshes, brackish marshes, and mudflats
Wetlands Like other wetlands, estuaries are highly productive environments that support diverse communities on land and in water.
The sediment falls to the bottom of the Bay, making it an important natural sink for many elements and compounds.
The Bay's nutrient-rich waters support a significant community of primary producers. Coastal forests, marshlands, shore grasses, and submerged aquatic vegetation (SAV) provide food and shelter for animals.submerged aquatic vegetation
The Bay is home to nearly 300 species of fish. Globally, the productivity of estuaries has declined in recent years as human populations have increased along their shores.
Estuaries across the globe have similar characteristics. They lie between land and ocean, contain a mixture of salt water and fresh water, and accumulate large amounts of sediment and organic material.
Esturaries SAV—Submerged Aquatic Vegetation These plants are sources of food and habitat for many shellfish, finfish, birds, amphibians, reptiles, invertebrates, and mammals
Esturaries Wetlands The high primary productivity in the wetlands fuels food webs
Estuarys Filter Feeders These organisms filter suspended particles to obtain food by straining the water. Anything not eaten is bound with mucus and discarded http://www.youtube.com/ watch?v=VTuBbuUro4g http://www.youtube.com/ watch?v=VTuBbuUro4g
Estuarys Pit Stops for Migratory Birds The North American migratory flyways describe the routes followed by migratory birds
Estuarys Habitats for Endangered Species like sea turtles and manatees.
Natural, Economic, and Aesthetic Values – Recreation and coastal industries
One reason the Bay is so productive is because it is shallow.
Aquatic plants receive plenty of sunlight—even those that live on the bottom. Aquatic plants are grouped into three categories based on the way they grow - floating, emergent (rooted at the water's edge, but their stems and leaves grow above the surface of the water. Cattails, cordgrass, and rushes are examples), and Submerged aquatic vegetation (SAV) which is critical in the recycling of nitrogen and phosphorous that would otherwise dissolve in the water which controls the population of algae.
Changes in sea level When the tide is high, large expanses of sand and mud may be covered by water. When the tide goes out, that land becomes exposed to air. This pattern of immersion and exposure creates a very stressful environment. Known as the intertidal zone,intertidal zone
Dead Zones Runoff from land carries sediment and nutrients into the Bay. Runoff Sometimes the runoff contains high levels of fertilizers washed from farms, suburban lawns, golf courses, and sewage plants.
Dead Zones Fertilizers contain large amounts of nitrogen and phosphorous, that can cause a sudden population explosion called an algal bloom. can survive.algal bloom
Dead Zones Any increase in these nutrients is called eutrophication. eutrophication
Dead Zones The algae begin to die and sink to the bottom. decomposers use up all the oxygen. Oxygen is an important limiting factor. Without it, the ecosystem collapses and the area becomes a dead zone where very few organisms can survive. dead zone
Development Pressures As the human population increased, critical habitats in the watershed were destroyed and the competition for the resources in the Bay became overwhelming.
The Chesapeake Bay ecosystem degraded. Scientists use the term population density to describe the concentration of a species.population density
Improperly treated sewage, excessive runoff, increased animal manure, soil erosion, and heavy use of fertilizers.erosion
a single known source, it is considered a point source.point source
When the pollution does not come from a single known source, it is a non-point source.non-point source
Riparian forest occur when trees line a riverbank, their roots bind the soil and reduce erosion. Riparian trees and wetland plants filter about 80% of the phosphorous and about 90% of the nitrogen from the water. By slowing water flow, the plants also trap sediment. Riparian forest
Filter feeders, such as oysters and clams, filter food particles from the water. The oyster filters and absorbs the nutrients but treats the abiotic sediment as waste which are heavy enough to sink to the bottom of the bay making the water less turbid.
Today, however, the population of oysters is less than 1% of its former size. The loss of oysters due to overfishing, diseases, loss of habitat, and low oxygen has significantly affected water quality.
One way to help wild oysters and other aquatic populations to recover is to "farm" seafood. Farming aquatic organisms underwater is called aquacultureaquaculture