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Summer/Fall 2002 Vol. 2 No. 2

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Heron in mangroves; photo by Heather Henkel, U.S. Geological Survey Murky Waters

Will Everglades Restoration Clarify
Nearby Bay?

The 850 square miles of water that make up Florida Bay is rarely much more than about a meter deep, a fact that would lead you to believe it should be no trouble seeing the sandy bottom regardless of where you stand. This was true 30 or 40 years ago. But in the 1980s, it started getting cloudy from increasing algae growth and suspended sediment. At the same time, dense meadows of turtle grass common to the bay began to die off.

The prevailing assumption in Florida was that high salinity -- partly caused by lower freshwater inflows from the nearby Everglades -- was to blame for the loss of grass and muddying of the water. So when a joint federal-state task force said that it wanted to elevate water levels in the Everglades as part of a multibillion-dollar restoration effort, many people figured the water clarity in the bay, which receives much of its fresh water from the Everglades, would improve.

But a new report from a Research Council committee advising the task force on scientific matters questions whether more fresh water is really the answer to a problem that may not have been caused by too much salt to begin with. It calls the evidence linking high salinity to the loss of turtle grass "debatable," and says that some scientists suspect the bay's environmental woes are in fact due to nutrient pollution, which fresh water from the Everglades may bring more of. And even if the Everglades restoration plan is fully implemented, it is unclear how much fresh water will actually flow into the bay, with some models predicting little change from current levels by the year 2050.

Ironically, efforts to return the bay to its grassy, pristine self may not be what nature intended. Historical accounts from the 19th century describe a murky body of water, not a clear one.

A more reliable characterization of the bay's historical condition and a focused technical review of how the Everglades restoration plan will affect the bay are needed, the committee said.    --Bill Kearney

Florida Bay Research Programs and Their Relation to the Comprehensive Everglades Restoration Plan. Committee on Restoration of the Greater Everglades Ecosystem, Water Science and Technology Board and Board on Environmental Studies and Toxicology, Division on Earth and Life Studies (2002, 54 pp.; ISBN 0-309-08491-1; available from National Academies Press, tel. 1-800-624-6242; $18.00 plus $4.50 shipping for single copies).

The committee was chaired by Jean M. Bahr, University of Wisconsin, Madison. The study was funded by the U.S. Department of the Interior.

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Copyright 2002 by the National Academy of Sciences