Gulf dead zone misses forecast, is still bigger than goal size
By Perry Beeman, Des Moines Register.com30 July 2013
This year’s dead zone in the Gulf of Mexico is smaller than expected, but still significantly bigger than a federal task force’s goal.
The oxygen-free zone — the result largely of fertilizer runoff from the Midwest — covers an area bigger than Connecticut.
Researchers had expected a near-record zone of hypoxia, or low oxygen, at 7,300 to 8,600 square miles because of heavy spring rains and unused fertilizer runoff from last year’s drought-shrunken corn crop. The Louisiana Universities Marine Consortium’s cruise aboard the Pelican found a zone of 5,800 square miles instead.
Last year, the dead zone was 2,889 square miles, the fourth-smallest on record, because of the drought, the National Oceanic and Atmospheric Administration reported.
The record, in 2002, was 8,481 square miles, and the smallest was 15 square miles in 1988.
The average over the past five years has been 5,176 square miles.
The federal task force working on the dead zone, or hypoxic area, wants the airless area reduced to 1,930 square miles.
The low-oxygen condition is caused in part by Midwestern crop fertilizers, which cause algae to grow in the Gulf. When the algae die, they consume oxygen, forcing sea creatures to move elsewhere or die. That disrupts one of the nation’s top fisheries.
Iowa is the nation’s top corn grower and the source of some of the biggest nitrogen loads heading down the Mississippi River to the Gulf.
“Giving a voice to the majority of Iowans who share this concern, we have repeatedly called on state leaders to set clear, measurable goals for reducing Iowa’s contribution to the Dead Zone,” said Ralph Rosenberg, executive director of the Iowa Environmental Council.
A coalition of environmental groups called the Mississippi River Collaborative sued the U.S. Environmental Protection Agency last year to force the agency to set and enforce numeric standards for nitrogen and phosphorus in waterways. In Iowa, the pollution makes it more expensive to treat drinking water and fouls rivers and lakes used by paddlers, boaters and swimmers, Rosenberg added.
Louisiana scientists said high winds in the southern part of the Gulf kept the dead zone smaller than had been predicted, preventing hypoxia from forming in some places this summer.
Not only was the area smaller than expected, but oxygen levels were relatively high, even in the dead zone.
“At stations where hypoxia was found, the values were extremely low and close to zero,” said LUMCON’s Nancy Rabalais and fellow researcher Eugene Turner of Louisiana State University.
The news from last week’s cruise of the Pelican, LUMCON’s ship, comes a week after Iowa Agriculture Secretary Bill Northey told a Farm Bureau conference in Ames that the voluntary projects outlined in the state’s Nutrient Reduction Strategy — similar to approaches used while the dead zone grew during the past several decades — remain the answer to cutting runoff pollution.
Northey contended regulations won’t work, and more progress will come from working with farmers on voluntary conservation and nutrient management.
The Gulf Restoration Network wasn’t buying that argument Monday. Once again, the group called for setting numeric standards for nitrogen and phosphorus.
“Since states have chosen to drag their feet on reducing dead zone-causing pollution in a significant way, it is EPA’s responsibility to set strong standards,” said Cynthia Sarthou, executive director.
Ditto for another nonprofit, the Prairie River Network.
“It’s long past time for us to get serious about curbing the dead zone pollution,” said Glynnis Collins, executive director. “Cities are rising to the challenge of tighter controls on sewage treatment plant discharges because the Clean Water Act forced them to. Now we need leadership from Congress to tackle tough national policies to reduce pollution from agriculture.”