The 2015 area of low oxygen, commonly known as the ‘Dead Zone,’ measured 16,760 square kilometers (= 6,474 square miles) as of Jul 28 – Aug 3, 2015 at the end of the 31st such cruise to measure the area of hypoxia (low oxygen) in the northern Gulf of Mexico. Based on the May nitrogen load from the Mississippi River, the area was predicted by Gene Turner, Louisiana State University, to be 15,210 square kilometers (5,875 square miles). The size is larger than the prediction. Continued Mississippi River discharge above average in June and record breaking high discharge in July brought more fresh water and nutrients from the River basin than usual for this time of the year.

This year’s ‘Dead Zone” is the size of Connecticut and Rhode combined, and is the 11th largest in size since the area has been mapped beginning in 1985. It is 28 percent larger than in 2014.
The average size for the last five years, including this year, is 14,024 square kilometers (= 5,543 square miles) and is three times larger than the environmental target (5,000 square kilometers; 1,991 square miles) approved by a federal/state task force in 2001 and maintained by the same task force in 2008. The 30 year average (less 1989) is 13,752 square kilometers (5,312 square miles.)

For more details please see http://gcoos.tamu.edu/documents/Hypoxia-LUMCON-2015.pdf.