Scientists supported by the National Oceanic and Atmospheric Administration say the size of this year's Gulf of Mexico oxygen-free "dead zone" is the fourth smallest since mapping of the oxygen-free area began in 1985.
The hypoxic zone forms each summer off Louisiana and Texas and threatens commercial and recreational Gulf of Mexico fisheries.
“The smaller area was expected because of drought conditions and the fact that nutrient output into the Gulf this spring approached near the 80-year record low,” Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium, said in a statement.
What wasn’t expected was how scattered the distribution of the dead, or hypoxic, zone was, said Rabalais, who led the survey. The patchy distribution “differed from any others documented in the past,” she said.
“Confirmed, however, is the strong relationship between the size of the hypoxic zone and the amount of fresh water and nutrients carried to the Gulf by the Mississippi River,” she said.
The 2012 area is approximately 2,889 square miles, slightly larger than Delaware.
Last year, flood conditions carried large amounts of nutrients that resulted in a dead zone measuring 6,770 square miles, an area the size of New Jersey.