The Chesapeake Bay is America's largest estuary and one of the world's most productive. The Bay is home to over 2,700 species. It draws water from over 150 rivers, streams, and creaks, receiving roughly 70,000 cubic feet of water every second. That water reflects the surrounding land use activities of the District of Columbia, parts of New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. A total of about 15 million people reside in the Chesapeake Bay water shed. This means that the Bay must process more land-based pollution that most bodies of water. .
Water quality and living resources in the Chesapeake Bay that declined steadily over the last several decades have begun to show improvement. Bay grasses, which perform crucial functions in the ecosystem, have increased throughout the Bay. The oyster and blue crab catch, however, continues to dwindle, and some find fish populations have declined. Species, such as striped bass have increased to the point that they are commercially viable again. .
The Chesapeake Bay's decline was evident as early as the 1950s. In the late 1970s, state and federal scientists began an extensive study to determine the reasons for the Bay's decline. Three major problems were identified; excess nutrients from wastewater, agricultural lands, and developed land; sediment in runoff from farms, construction sites, and eroding lands; and possible elevated levels of toxic chemicals. .
Nitrogen and phosphorus are considered good things because they support the bottom of the food chain. But in recent years the Chesapeake Bay has been receiving too much of these nutrients. The excess nutrients have created large blooms of microscopic plants called phytoplankton. The growth of phytoplankton has cut off the supply of light to underwater grasses. The underwater grasses are essential part of the Bay's ecosystem because they provide a habitat for many species and help filter the water.
