Scientists project large ‘dead zone’ in Gulf this summer

An area of low oxygen to form this summer off the coast of Louisiana could grow to the size of New Jersey if forecasts released Tuesday hold true.

That area of low oxygen, also known as the “dead zone,” could be one of the largest scientists have seen since annual monitoring began in 1985, according to the National Oceanic and Atmospheric Administration.

The 2013 NOAA forecast calls for a “dead zone” of low oxygen to end up covering 8,561 square miles. There’s a 95 percent confidence that the size of this year’s dead zone will be between 7,634 square miles and 9,517 square miles if no tropical storms occur before or during the annual testing cruise in late July.

Funded through NOAA, the forecasting, monitoring and other “dead zone” work in the Gulf of Mexico is done by the Louisiana Universities Marine Consortium, Louisiana State University and the University of Michigan.

“Hypoxia is a critically important national issue,” said Ben Sherman, a NOAA spokesman.

In a news release on the latest forecast, NOAA included information about low oxygen areas in Chesapeake Bay to highlight that it isn’t just a problem for the Gulf of Mexico.

In the Gulf of Mexico, a yearly cruise headed by Nancy Rabalais, executive director of LUMCON, is done in July to measure the size of the “dead zone” at that time.

The forecast, done by Gene Turner, a professor in the LSU School of the Coast and Environment at LSU, takes into account the amount of water flowing from the Mississippi River in May and the amount of nutrients such as fertilizers in the water.

This May, the amount of water flowing down the Mississippi River was above normal, which means more nutrients were streaming into the Gulf of Mexico. The U.S. Geological Survey estimates that 153,000 metric tons of nutrients flowed to the Gulf in May, which is 94,900 metric tons more than last year’s amount, according to information from NOAA.

The nutrients feed small organisms that die and fall to the bottom of the water column, where they use up oxygen as they decompose.

The lower levels of water are heavier than the fresh water coming from the Mississippi River, and without storms to mix the oxygen-carrying upper layer of water with the lower layers, oxygen levels drop below what is needed to sustain marine life.

The size of the dead zone fluctuates and is at its most severe in the summer months.

The Mississippi River/Gulf of Mexico Watershed Nutrient Task Force in 2008 released an action plan that set a goal of reducing the five-year average of the “dead zone” down to 1,930 square miles but that goal hasn’t been met.

“There’s been no progress as far as I can tell,” said Turner. “There is a reluctance to see it as a water quality problem.”

The large size of the “dead zone” forecast for this year comes in part because of the drought last year up river, Turner said.

He said it was so dry that nutrients and water weren’t washed through the drainage systems located under many agricultural fields. As a result, he said, nutrients and fertilizer placed on the soil this year added to amounts that were already in the system.

Turner said some have suggested using some of the money from Deepwater Horizon fines from the 2010 oil disaster in the Gulf of Mexico to work on nutrient reduction upstream.

“It’s such a novel way to look at this, not state by state, but as an agricultural system,” Turner said.

Funding to continue the work of forecast, modeling and sampling is uncertain for the future, Turner and Rabalais said. Although the work was funded through 2014, there’s been no word on what the next year’s allocation could be or if it’s coming, Turner said.

Funding last year, when it arrived, had been cut by 43 percent not counting an additional cut in boat time to do field work, Turner said.