The Associated Press

NEW ORLEANS - Louisiana, a state working against time to keep its coast from sinking into the Gulf of Mexico, is looking to the Midwest for help with a related problem - a seasonal "dead zone" in the Gulf.

The problem is that nitrogen-rich water from streams that empty into the Mississippi River feeds a population boom of one-celled organisms - so many that when they die and decompose at the bottom, the process eats oxygen out of the water from the bottom up.

That creates a dead zone in the Gulf that's usually 6,000 to 7,000 square miles, though tropical storms this year churned up the water and mixed oxygen back in, shrinking it to 3,300 square miles in July - the annual measurement month.

Wetlands and forests usually trap and use nitrogen and other nutrients carried off of fields in rainwater and turning a tiny fraction of Midwestern farmland back to marshes or swamps and returning forests to riversides and floodplains could go a long way toward a dead zone solution, researchers say.

Louisiana's coastal erosion - 25 to 30 square miles a year - is also inextricably tied to the Mississippi River. Flood control levees throughout the basin keep the Mississippi's waters within its banks. But without the mud floods leave behind the land sinks a bit every year, until it is underwater.

Louisiana's coastal restoration program is paying $150,000 to have researchers at Ohio State and Louisiana State universities figure out how much new upriver wetlands are needed to cut back the dead zone, where they should go and how they should be set up.

If a wetland isn't the right size and in the right position, it won't be much help, said John Day, LSU's chief researcher. His counterpart at OSU is William Mitsch, who has created 30 acres of swamp and marsh on some university land north of the main campus.

"Together, north and south, we can tackle this problem," Mitsch said. "Louisiana has a hypoxic dead zone that's due to runoff from farms throughout the Mississippi watershed. A large restoration of wetland areas in the Midwest is the answer."

It also would mean better water, better flood control and more wildlife habitat across the Mississippi basin, Day said. Water treatment plants across Iowa need expensive nitrate-removal systems to meet federal guidelines.

"We're not just asking the rest of the Mississippi basin to do something for us," Day said. "There's a generalized benefit over the whole basin."

The current estimate is that about 5 million acres of wetlands and 19 of forest would be needed. The wetlands might take 3 percent of current farmland in affected states, Day said.

"This is not an attempt to point fingers at farmers," he said. "The upper Midwest has an $80 billion-a-year farm economy. They're producing food that feeds us all.

"We want to work with the farmers to produce programs that will allow them to do their job - produce food - in the most cost-effective way, and at the same time improve water quality."