A Look at the Chesapeake Bay 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. Pollution has reduced the grasses to only 10% of their historic levels, from 600,000 acres to around 65,000 acres today. Another problem occurs when algae dies and begins to decompose. The process of decomposition removes dissolved oxygen from the water and turns large sections of the Bay into dead zones where life can not be supported.
The presence of phosphorus in the Chesapeake Bay has been receiving extra attention because of its possible role in outbreaks of the toxic microbe pfiesteria. Pfiesteria is suspected to cause lesions on fish in the Bay. There are currently studies underway searching for a correlation between fertilizer runoff and the outbreak of Pfiesteria.
Toxins, such as the heavy metals mercury, cadmium, copper, lead, zinc; and pesticides, dioxins, polychlorinated biphenols (PCBs), polynuclear aromatic hydrocarbons (PAHs), and many other chemicals have been identified as a potential threat to the Bay. Toxic substances are poisonous to humans and other living things and have been known to cause a wide range of negative health effects. There are over 70,000 chemicals currently in use. Less that 2% of these chemicals have been adequately tested for their impact on human health and the environment. The testing, monitoring, and controlling of toxic substances is very complex and expensive. As a result, not enough is known about the kinds and amounts of toxic chemicals entering the Bay or the effects they have on the living things in the Bay?s water.
There are three basic ways that pollution gets into the Chesapeake Bay. The first is point source discharges such as sewage treatment plants, industrial facilities, and food production and processing facilities. They discharge nutrient and toxic-laden wastes, often through pipes, directly into the water. Some facilities carry their wastes off site and spread them across the land, where they eventually flow into the water. Many point source dischargers have made progress in reducing the amounts of pollution they dump into the water, but far too many nutrients and toxins still enter the Bay. As long dischargers are permitted to use lakes, oceans and bays as dumping grounds waste, point source pollution will continue as a problem for the Bay.
A second way pollution enters the Bay is through precipitation. Whenever rain or snow falls on the ground and picks up contaminants and carries them into streams and rivers that will eventually flow into the Chesapeake Bay. Polluted stormwater runoff has become an increasing problem because much land around the bay has changed from the natural filters of forests and wetlands to poorly managed farmland, construction sites, city streets, and suburban communities. Construction sites and farmland severely erode, sending tons of soil into the water. A well managed farms send ten times the amount of sediment into the Bay as a forest. A construction site can send a thousand times as much sediment as a forest. Farms are a significant source of nutrient, bacterial and toxic pollution when stormwater runs off farmland saturated with animal wastes and other fertilizers. One of the largest contributors of farm runoff is the Eastern Shore?s chicken industry, which produces around 400,000 tons of chicken manure. When rain falls on the roadways in urban and suburban areas, it washes harmful gasoline and oil from the roads into the Bay.
Although not often thought of, air pollution is the third source of pollution in the Chesapeake Bay. Nitrogen, phosphorus, acid rain and other airborne toxins are continually being dropped over Chesapeake Bay and its watershed. Sources of air pollution like cars, trucks, boats and lawn mowers produce millions of tons of pollution in the surrounding region every year. Stationary sources like power plants and factories, some hundreds or even thousands of miles away, do the same. These various pollutants eventually settle directly into the Bay or on land where stormwater eventually carries them into the Bay.
Efforts must be taken by the government and individuals to help reduce the amount of pollution deposited in the bay. Restrictions need to be made on the amount of pesticides used in the Bay?s watershed. Erosion must be decreased through more responsible planting, and construction site layout. Air pollution needs to be combated through the use of technology to make cleaner burning engines, power plants, and factories.
Cleanup and preservation efforts must continue to work hard at restoring the Chesapeake Bay ecosystem. The Chesapeake Bay is a unique environment that supports a great number of species. Work must continue to prevent the destruction and pollution of their natural habitat. The marine life of the Bay is essential not only to the health of the Bay ecosystem, but it is a mainstay of the economy in the surrounding areas. The threat of polluted aquatic life also poses a potential threat to the humans that consume the seafood from the Bay. If the Bay continues to be polluted the tourist and seafood industries of Maryland and Virginia could suffer greatly.