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History of Dead Zones (Chesapeake Bay)
The Chesapeake Bay, on the East Coast of the United states, was one of the first dead zones ever identified. It was discovered and investigated in the 1970s. Chesapeake Bay contains unusually high levels of nitrogen, caused by two factors: agriculture and urbanization. The Eastern part of the bay is lined with poultry farms. These farms contains large amounts of manure which are rich in nitrogen, that wash into the bay. At the western part of the bay there are numerous factories and urban sprawls that emit nitrogen into the air from pollution and urban greenery which uses nitrogen fertilizer. In addition, there is nitrogen found in the atmosphere across the globe, which enters all bodies of water. In Chesapeake Bay atmospheric nitrogen accounts for only one third of the nitrogen found. (Paine, 2012)
To the right is the annual hypoxic levels of oxygen found in Chesapeake Bay. Levels vary annually because of seasons which effect urban areas.
By Alea Chedekel
(Paine, 2012)