Where Is It Happening?
Ocean dead zones occur off coastlines of high polluting cities or agricultural cultivated areas. The majority of the ocean’s dead zones lie on the eastern coast of the United States, the coastline of the Baltic Sea, Japan, and the Korean Peninsula (2). There is a 8,500 square miles dead zone in the Gulf of Mexico due to the Mississippi River draining the nutrients from the heavy agriculture in the Midwest. It is currently the size of New Jersey and will continue to grow if nothing is done about it. If we stop the eutrophication process, the dead zone will decrease with time. However, with the recent BP oil spill in the Gulf of Mexico, hurricane Katrina causing increased nutrient runoff, and the continuing pressure to increase the Midwest’s food production, this dead zone is not looking like it will dissipate any time soon (10). With an emphasis on corn production for ethanol, there is a bigger need for chemical fertilizers since this crop requires a large amount of nitrogen. “The U.S. Geological Survey estimated that 153,000 metric tons of nutrients flowed down the swollen Mississippi and Atchafalaya rivers during May—a 16% increase over the nutrient load average seen during the past 34 years” (4).
How Fast Is It Happening?
In 1960 there were 10 documented ocean dead zones. Less than 50 years later in 2007 there were 169 documented dead zones. Currently there is an estimated 405 dead zones worldwide. There is roughly 95,000 square miles of ocean dead zone, the size of New Zealand (2). As well as the number of dead zones increasing, the size and severity of these zones are worsening. This is because the main causes of cultural eutrophication: population growth, increased intensive agriculture, and industrial processes, are all still increasing. Currently there are only 13 dead zones in recovery, such as San Francisco Bay and the Hudson River while there are still 233 areas of concern (9). This problem is not dissipating and in fact is increasing at an exponential rate. If dead zones continue to worsen as rapidly as they have been in the last few decades, we may not be able to reverse it in time (8).
"Dead zones are becoming more common worldwide in areas where coastal waters are swamped with nutrients, particularly nitrogen, from sewage or fertilizer," according to NOAA scientists
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