Muddy waters: letting the Gulf of Mexico breathe again

June 14, 2001

COLUMBUS, Ohio - Saving the Gulf of Mexico from polluted runoff is possible, but it means creating or restoring at least 5 to 13 million acres of wetlands in the Midwest and the lower Mississippi River basin, according to a new report by environmental researchers.

Led by William Mitsch, a professor of natural resources and environmental science at Ohio State University, the scientists also recommend creating or restoring 19 to 48 million acres of streamside forest areas.

Together, that's at least enough created and restored wetland and forested area to fill all of West Virginia. The report appears in the May issue of the journal Bioscience.

It's estimated that the American Midwest has lost about 80 percent of its wetlands in the last two centuries, compared to a 50 percent loss in the contiguous United States. Wetlands create buffers between agricultural lands and streams and rivers. They also reduce the level of chemicals - agricultural and otherwise - that wash into waterways.

Under current conservation programs, about 577,000 acres of wetlands have already been created or restored. About 10 to 25 times more wetlands are needed to cause a significant reduction of nitrogen levels in the Gulf, said Mitsch.

"There are countless federal programs to help support wetland restoration and creation," he said. "And that may help solve half of the problem. It could cost anywhere between $300 to $2,000 per acre to restore and create wetland areas in the Midwest; it's less expensive to create a wetland in an area that used to be a wetland."

In comparison, Mitsch said efforts to restore the 1.4 million acre Everglades National Park is costing taxpayers about $8 billion. The Mississippi River feeds the Gulf of Mexico, and the Mississippi River basin includes 40 percent of the lower 48 states. Runoff from watersheds in the basin eventually makes its way to the Gulf.

That runoff is full of nitrogen and other chemicals that algae thrive on, experts say. Resulting algal blooms deplete the water of nearly all dissolved oxygen, turning the Gulf each spring into what's been termed a "dead zone." Dissolved oxygen levels dip below 2 parts per million, and most aquatic species can't live in waters containing less than 2 ppm of oxygen. Dissolved oxygen levels in the Gulf are normally about 5 to 10 ppm.

The "dead zone" typically begins in the spring, when planting and fertilizing fields peaks. The accumulation of nitrogen and other chemicals usually reaches a maximum in midsummer and disappears in the fall, Mitsch said. While the size of the zone varies from year to year, it has encompassed more than 7,000 square miles of the Gulf.
Mitsch co-authored the report with John Day, of Louisiana State University; J. Wendell Gilliam, of North Carolina State University; Peter Groffman, of The Institute of Ecosystem Studies in Millbrook, N.Y.; Donald Hey, of the Wetland Initiative in Chicago; Gyles Randall, of the University of Minnesota; and Naiming Wang, of the South Florida Water Management District.

Written by: Holly Wagner, 614-292-8310;

Ohio State University

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