Gulf of Mexico Faces Record-Breaking Dead Zone With Devastating Consequences

This year may be one of the deadliest for marine life who call the Gulf of Mexico home, a number of researchers warn.

NOAA-supported models at the University of Michigan, Louisiana State University and the Louisiana Universities Marine Consortium forecast that the hypoxic "dead" zone located along the shores of the gulf will stretch between 7,286 and 8,561 square miles, resulting in a biological desert.

Should this be the case, 2013 would rank in the top 10 for largest dead zones ever recorded and represent a major set back for regional fisheries and overall economy, NOAA reports.

However, the estimate is based on the assumption that no significant tropical storms will occur in the two weeks preceding or during the official measurement survey period scheduled from July 25 to Aug. 3, which could drop the dead zone to a low of 5,344 square miles, or roughly the size of Connecticut.

Hypoxic, or very low oxygen, and anoxic, no oxygen, zones are the result of excessive nutrient pollution, largely from human activities such as agriculture, which causes insufficient oxygen to support marine life in near-bottom waters.

Other, more natural aspects such as wind speed, wind direction, precipitation and temperature all impact the size of dead zones as well.

This year's prediction for the Gulf reflects flood conditions in the Midwest that resulted in the transportation of a large number of nutrients from the Mississippi watershed to the region and comes five years after the Mississippi River/Gulf of Mexico Nutrient Task Force established the goal of reducing the dead zone to less than 2,000 square miles annually.

During May 2013, for example, stream flows in the Mississippi and Atchafalaya rivers were above normal, with estimates from the U.S. Geological Survey (USGS) pointing to some 153,00 metric tons of nutrients transported downriver, compared to last year's 58,100 metric tons.

Meanwhile, a second NOAA-funded forecast for the Chesapeake Bay estimates a smaller-than-average dead zone for the nation's largest estuary with a mid-summer hypoxic zone of 1.46 cubic miles, a mid-summer anoxic zone of 0.26 to 0.36 cubic miles and a summer average hypoxia of 1.10 cubic miles - all of which represent the low end of previously recorded zones measured in cubic miles due to its shallow nature.

For the Chesapeake Bay, the USGS estimates 36,000 metric tons of nutrients entered the region from the Susquehanna and Potomoc rivers between January and May. This number represents a 30 percent decrease from the average.

According to Donald Boesch, president of the University of Maryland Center for Environmental Science, the measurements from both areas are key in understanding and dealing with the potentially problematic ebb and flow of hypoxic and anoxic zones.

"Coastal hypoxia is proliferating around the world," he said. "It is important that we have excellent abilities to predict and control the largest dead zones in the United States. The whole world is watching."

The confirmed size of the 2013 hypoxic zone is due to be released in August, following a monitoring survey led by the Louisiana Universities Marine Consortium beginning in late July and, once out, will help to improve future forecasts.

In the case of the Chesapeake bay, however, the final reading is not due until October following surveys by the Chesapeake Bay Program's partners from the Maryland Department of Natural Resources and the Virginia Department of Environmental Quality.

Both forecasts are based on nutrient run-off and river stream data from the USGS with the Chesapeake data funded with a cooperative agreement between USGS and the Maryland Department of Natural resources. Finally, the numbers taken from these sources are inserted into models developed by funding from the National Ocean Service's National Centers for Coastal Ocean Science.