How People Almost Destroyed the Ecosystem of the Bay

The Chesapeake Bay is an ecosystem, composed of living parts: animals, plants and microorganisms. Those parts are depends on each other. Take away or change some of this parts, and the whole system feels the effects.
For many years the Chesapeake oyster was the number one resource. With the demand for oysters its population in the Bay fell. The oysters are filter feeders. An oyster pumps about 50 gallons of water a day in order to filter out algae, the tiny floating plants that serve as its primary food source. As oysters feed, they act like filters in a swimming pool, drawing out algae and clearing the water. Because oyster populations now on such low level, it would now take a year or more for today’s oysters to filter that same amount of water.
Picture displays how algae negatively affect the world under water
The Bay now has too much algae floating through the water. It is mean the lack of light for underwater grasses. Those grasses in many places may provide food for diving ducks or shelter for molting crabs. Many grasses now have disappeared, leaving large stretches of Bay bottom bare.
Picture of 'tired' Earth To make it shorter:

     People harvested oysters and destroyed the oyster reefs.

     Peoples activity Increased amount of algae in the water by adding more nutrients. Those nutrients come from sewage treatment plants, from fertilized farm fields. These nutrients cause even larger blooms of algae, which die and decompose on the Bay floor, a process that draws life-sustaining oxygen out of the water.

     People torn away the forests, cleared the land for agriculture. This increased the amount of the dirt washed to the Bay during the storms and heavy rains. Soil erosion continues today also because of construction and other land development in the watershed. Every construction site has the potential to release tons of sediment into the Bay.

     People added new chemical compounds to the Bay. Heavy metals like zinc and mercury from industrial uses, pesticides from farms and suburban lawns, cleaning solutions from households, and a host of petroleum products all wash off the land into the streams and the rivers that feed the Bay.

Human beings rely on this Bay as much as any animal; and we also bear a special responsibility, since our actions have an impact on the ecosystem greater than that of any other creature that walks the Earth.