The primary nutrients polluting the Chesapeake Bay are nitrogen and phosphorous. High amounts of these nutrients increase the growth of algae. Algae become so abundant that the color of the water turns brownish or greenish. Sunlight is blocked from reaching other plants. When the algae die and decompose, oxygen dissolved in the water is used. Often, so much oxygen is used by decomposing algae that fish and other animals must move to areas with more oxygen. Plants and animals that cannot move may die.
Excess sediment contributes to poor water quality by blocking the sunlight needed support important aquatic habitats (submerged aquatic vegetation beds), which in turn impacts the shellfish and finfish that need these habitats to survive. A good source for more information about sediments in the Chesapeake Bay is A Summary Report of Sediment Processes in Chesapeake Bay and Watershed.
Landscape changes affect nutrient and sediment pollution to the Chesapeake Bay, too. For instance, development pressure increases pollution from urban land use despite implementation of Best Management Practices. Conversely, as agriculture declines in Maryland, nutrient and sediment pollution from agriculture declines.
Toxics or chemical contaminates and air pollution are important contributors to Chesapeake Bay pollution and will be added to the BayStat pages over time.
To learn more about pollution sources in your region, click on the image to the right, select a pollutant category and your basin of interest to see the percentage contributions and trends. Right now, the information is available Statewide and for the 10 major tributary basins. We are moving in the direction of providing this information for counties and smaller watershed basins with the development of new computer models, and that information should be available in 2008-2009.
Data contained in these charts are from the Chesapeake Bay Program Phase 4.3 Watershed Model. For more information about this model or other environmental models, go to http://www.chesapeakebay.net/restrtn.htm
