"This year's record Mississippi River floods are forecast to create the biggest Gulf of Mexico 'dead zone' since systematic mapping began in 1985, U.S. scientists reported on Tuesday.
Often created by farm chemical run-off carried to the Gulf by the Mississippi, the 2011 low-oxygen 'dead zone' could measure 8,500 to 9,421 square miles (22,253 to 26,515 sq km), or an area roughly the size of New Hampshire, the U.S. Geological Survey said in a statement.
This would be bigger than 2002's record-large hypoxic zone, which stretched over 8,400 square miles (21,750 sq km).
The hypoxic zone threatens commercial and recreational Gulf fisheries. In 2009, the dockside value of commercial Gulf fisheries was $629 million. Recreational fishers contributed more than $1 billion to the Gulf economy taking 22 million fishing trips, the survey said in its statement.
Seen year-round but most pronounced in summer, the 'dead zone' threatens resources including humans who depend on fish, shrimp and crabs, which need oxygen to survive. The zone typically is located on the bottom of the continental shelf off Louisiana and Texas."