Chesapeake Bay has been for many years a symbol for excessive pollution with the large amount of fertilizers, animal waste and other pollutants making their way into the largest estuary in United States.
However, the pollution levels seem to be finally decreasing. This was the conclusion of the major study coming from the Johns Hopkins University and the University of Maryland Center for Environmental Science published in the the November 2011 issue of Estuaries and Coasts..
The researchers have discovered that the size of dead zones (areas with very little or no oxygen where plants and animals cannot live) leveled off in deep channels of the bay during the 1980s and has been declining ever since.
This timing corresponds with the introduction of multistate-federal Chesapeake Bay Program that went live in 1980s and whose goal was to restore the water quality and health of the bay.
This is a clear evidence that the federal program has actually worked and that limiting nutrient pollution is the key factor in making Chesapeake Bay healthier. Under this program farmers were encouraged to plant natural barriers and take other steps to keep fertilizer out of waterways that feed the Chesapeake.
The other important factors that helped to reduce the levels of nutrients in Chesapeake Bay were forcing water treatment plants to pull more pollutants from their discharge, and different air pollution control measures that reduced the movement of nitrogen from the atmosphere into the bay.
The decrease in the nutrients will have to continue in order to achieve bay restoration goals. More nutrients cause faster algae growth and once the algae die, their remains sink to the bottom of the bay, where they are being eaten by bacteria. As they consume algae, the bacteria utilize dissolved oxygen in the water creating dead zones. This has lead to serious decreases in the Chesapeake's fish and shellfish populations.
Chesapeake Bay is home to a more than 3,600 species of plants, fish and other animals.