Dead zone in Gulf could be biggest ever recorded

HOUMA – Louisiana researchers are predicting that this year’s dead zone, the area of low-to-no oxygen that forms annually in the Gulf of Mexico, will be the largest ever recorded.

Scientists expect the so-called “dead zone,” which has earned its nickname by killing or driving away marine life from thousands of miles of oxygen-deprived Gulf waters, to grow to about 10,084 square miles – an area about the size of the state of Massachusetts that will reach over to the Texas coastline.

“Low oxygen conditions have been present off Terrebonne and Barataria Bays since March, and the number of stations that are hypoxic (or low-oxygen) is increasing,” said Nancy Rabalais, director of LUMCON.

The dead zone is caused during warmer months by excess nutrients dumped into the river from farming and waste run-off upstream, and scientists predict the problem will only worsen as demand for ethanol drives corn farming upstream.

“In the last few years, there’s been 20 percent more corn farming, and that’s a major source of nitrates,” said Eugene Turner, one of the lead researchers with Louisiana State University. “Also, some of those new corn fields are coming in on marginal lands so they don’t hold the soil as well.”

Flooding in the Mississippi this year could also have some influence on the size of the dead zone, Rabalais noted.

Scientists made the forecast by calculating the concentration of nitrates – nutrients that are often a product of farming and feed the phenomenon – as well as the flow of the river to create a model of the predicted dead zone.

The average size of the dead zone has been about 6,046 square miles since 1990, and scientists say that it has nearly doubled in size since the early years of mapping it.

“The size of the hypoxic zone last year was only slightly below the largest zone measured,” said Turner. “…Nitrogen loading to the Gulf of Mexico in May this year will be 37 percent higher than last year and the highest since measurements began in 1970.”