Scientists: dead zone stresses Gulf, action needed

By CAIN BURDEAU, Associated Press
3 August 2011


Scientists say the massive area of low oxygen in the Gulf of Mexico, known as the "dead zone" because it kills marine species, will create more problems unless fewer fertilizers are dumped into the Mississippi River.

Farm runoff is the leading cause of the high nitrogen and phosphorous levels in the Gulf and the increase in corn growing to meet new ethanol standards in gasoline will keep nitrogen levels high, scientists said. The warning was the theme of a gathering of scientists and policymakers Tuesday. The meeting brings together scientists working on a multistate federal task force studying the dead zone and members of the Gulf of Mexico Alliance, a group of state officials pushing to clean up the Gulf.

Since the 1970s, scientists have discovered that a massive area of low oxygen, known as hypoxia, forms each summer in a noxious cycle driven by the huge amounts of nutrient-rich waters that flow into the Gulf from the Mississippi River. The nutrients feed algae blooms, which in turn spark a massive growth in phytoplankton. The phytoplankton sinks to the bottom of the Gulf and decomposes, dramatically reducing the amount of oxygen in the water that animals need to survive. The dead zone kills many bottom-dwelling creatures, such as worms, crabs and shrimp. Fish can swim away, but it stresses them, too.

Scientists have been measuring the Gulf’s dead zone since 1985, and this year found that an area of about 6,765 square miles held too little oxygen in July to support most marine life. It was the 11th-largest dead zone on record. The 26-year average through 2010 was 5,200 square miles.

Scientists say evidence is mounting that the Gulf is getting closer to a breaking point. Other seas, such as the Black Sea and the Caspian Sea, have experienced ecological collapses in the past and scientists fear the Gulf could follow a similar path.

Recent studies show that the dead zone is hurting the reproduction of croakers, an important fish species. Also, new research suggests that the Gulf is becoming less capable of recovering from the dead zone each year.

"The longer the hypoxic zone is at this magnitude, it will be harder to shrink it," said Robert E. Magnien, the director of the Center for Sponsored Coastal Ocean Research at the National Oceanic and Atmospheric Administration.

Scientists worry that the Gulf has suffered too much harm in recent years. Last year, the Gulf was the site of the nation’s largest offshore oil spill when an oil rig drilling a BP PLC well exploded April 20. The out-of-control well spilled millions of gallons of oil.

"The Gulf is really resilient, it can bounce back. But the dead zone stretches the rubber band every year and the question is when does the rubber band snap?" said Larry McKinney, the director of the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University.

"I dove in the hypoxic zone once and it was a real eerie place," McKinney said. He said he saw small crabs and worms struggling to cling onto woody debris floating upward and out of the dead zone. The bottom of the Gulf where he dove was littered with dead species, he said.

Since the mid-1990s, the federal government has sought to study the problem more intensely and enact a plan to reduce the dead zone, but those efforts have not done much. The goal is to reduce the dead zone to about 1,900 square miles by 2015.

Congress has never approved funding for a plan to reduce the size of the dead zone and until that happens, it is unlikely that it will shrink substantially, said Doug Daigle, a member of a government-sponsored committee seeking solutions to the dead zone problem. A draft plan crafted by the Clinton administration proposed spending $1.5 billion over five years, but that initiative was never funded, Daigle said.

Bill Northey, the Iowa secretary of agriculture, said farmers are taking steps to reduce the amount of fertilizer they use and stop it from getting into the Mississippi. For instance, farmers are planting new corn and soybean plants that need less fertilizer and are building wetlands to filter runoff. He believed it was possible to reduce the nitrogen load and continue growing crops at present levels.

In 2009, the U.S. Department of Agriculture set up a program to help farmers in 12 states block fertilizer runoff. The goal is to spend $320 million over five years.

Daigle said that program was not large enough to deal with all the problem spots in the Mississippi basin, which drains 41 percent of the continental United States.


Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.