Largest Gulf ‘Dead Zone’ Anticipated in Wake of Spring Floods

The Gulf of Mexico’s hypoxic zone, an oxygen-depleted area created by excessive nutrient pollution, is expected to reach record proportions this year as a result of the extreme flooding in the Mississippi River basin,

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Gulf of Mexico Dead Zone Size

Nancy Rabalais LUMCON/NOAA
Size of the ‘dead zone,’ 1985-2011
according to a forecast by the National Oceanic and Atmospheric Administration (NOAA). Using nutrient load data compiled by the U.S. Geological Survey, scientists calculate that the hypoxic zone, also known as the “dead zone,” could cover 8,500 to 9,421 square miles, an area about the size of New Hampshire. The dead zone — which is created when algal blooms remove oxygen from the water and suffocate marine life — has reached an average 6,000 square miles during the last five years. But with the flow rate of the Mississippi and Atchafalaya Rivers nearly double the normal rate this spring, the quantity of nutrients entering the Gulf is about 35 percent higher than usual, according to NOAA. The dead zone, located along the coast, forces Gulf fishermen farther offshore.