A team of scientists from NOAA, the Louisiana Universities Marine Consortium, and Louisiana State University is forecasting that the "dead zone" off the coast of Louisiana and Texas this summer - an area of low or no oxygen which can threaten or kill all marine life in it - has the potential to be the largest since shelf wide measurements began in 1985. The "dead zone" is an area in the Gulf of Mexico where seasonal oxygen levels drop too low to support most life in bottom and near-bottom waters. It is caused by a seasonal change where algal growth, stimulated by input of nutrients such as nitrogen and phosphorus from the Mississippi and Atchafalaya rivers, settles and decays in the bottom waters. The decaying algae consume oxygen faster than it can be replenished from the surface, leading to decreased levels of dissolved oxygen.
This summer's "dead zone" may be as large as 8,500 square miles, an area about the size of New Jersey. Since 1990, the average annual hypoxia-affected area has been approximately 4,800 square miles; the "dead zone" measured 6,662 square miles in 2006. Although NOAA has predicted an active hurricane season for 2007, if no strong storms stir up the waters, this year's dead zone could equal the largest recorded and stretch into the continental shelf waters of Texas . This area is of particular concern because of its potential to affect valuable fisheries in the Gulf of Mexico.
For more information, read the NOAA news story.