Gulf of Mexico ‘dead zone’ expected to be average size this summer _lowres

Associated Press photo by Johnny Hanson -- First year Texas A&M oceanography student, Rebecca Gray, boards the research boat, RV Manta June 17, 2014, on Pelican Island in Galveston, Texas. She and a group of faculty and students from Texas A&M will study the 'dead zone' along the Texas and Louisiana coast.

The annual low-oxygen “dead zone” that forms every summer off the coast of Louisiana will be about average size this year, according to forecast modeling done through support from the National Oceanic and Atmospheric Administration.

Researchers at a number of universities including LSU and the Louisiana Universities Marine Consortium forecast that the dead zone will end up covering 4,633 square miles to 5,708 square miles this summer.

The actual size of the low-oxygen area will be measured later this year with results released in July or early August, according to a news release from NOAA.

Last year, the dead zone measured 5,840 square miles.

The Mississippi River Gulf of Mexico Watershed Nutrient Task Force has long set a goal to reduce the annual size of this dead zone to less than 1,930 square miles.

The forecast estimate is based in part on measurements of the amount of nitrates from fertilizer and other sources flowed down the Mississippi River into the Gulf of Mexico.

The nitrates that enter the Gulf of Mexico feed small organisms that use up oxygen as they die and fall to the sea floor.

Without windy weather from storms or weather fronts to help mix oxygen-rich water at the top with the low-oxygen layers of water at the bottom, low-oxygen conditions can accumulate to a point where levels drop too low to support marine life.