The Drought and the Gulf of Mexico Dead Zone
Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes, caused by "excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water. Currently, the Gulf of Mexico's dead zone, off the coast of Louisiana and Texas, is the most notorious hypoxic zone in the United States. The worst drought to hit the United States in at least 50 years does have one benefit: it has created the smallest dead zone in the Gulf of Mexico in years, says a Texas A&M University researcher who has just returned from gulf waters.
NOAA-supported scientists in July 2012 have found the size of this year’s Gulf of Mexico oxygen-free dead zone to be the fourth smallest since mapping of the annual hypoxic, or oxygen-free area began in 1985. Measuring approximately 2,889 square miles, the 2012 area is slightly larger than Delaware.
The survey also found a patchy distribution of hypoxia across the Gulf differing from any previously recorded. This is in stark contrast to last year, when flood conditions, carrying large amounts of nutrients, resulted in a dead zone measuring 6,770 square miles, an area of the state of New Jersey. The last time the dead zone was this small was in 2000 when it measured 1,696 square miles, an area slightly smaller than Delaware.
Oceanography professor Steve DiMarco, one of the world's leading authorities on the dead zone, says he and other Texas A&M researchers and graduate students analyzed the Gulf Aug. 15-21 and covered more than 1,200 miles of cruise track, from Texas to Louisiana. The team found no hypoxia off the Texas coast while only finding hypoxia near the Mississippi River delta on the Louisiana coast.