Scientists forecast an average-sized “dead zone” in the Gulf of Mexico this year of 5,483 square miles, “or about the size of Connecticut,” says the U.S. Geological Survey. The forecast was drawn from monitoring of nutrient runoff and streamflow in the Mississippi River basin, and from the combined projections of four forecasting models run by separate research groups. A monitoring survey led by the Louisiana Universities Marine Consortium from July 28-August 4 will result in a confirmed size for the hypoxic zone.
“The dead zone in the Gulf of Mexico affects nationally important commercial and recreational fisheries and threatens the region’s economy,” says the USGS. It estimates that 104,000 tonnes of nitrate and 19,300 tonnes of phosphorus flowed down the Mississippi River basin into the Gulf during May. The nitrate total was 21 percent below the average for 1980-2014 but phosphorus was 16 percent above its long-term average.
An average-size dead zone “is still much larger than the national goal of reducing the dead zone this year to 1,930 square miles – a goal that’s not going to be met because little has changed in the amount of nitrogen coming down the river, primarily from agricultural fertilizer,” said the Baton Rouge (La) Advocate. “Most of the nitrogen comes from upriver agricultural areas.”