Pollution Dogs Chesapeake Bay, Dead Zones Shift And Grow

[hatrack]

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"Some days, there's no sign of it in this shallow part of the bay off St. Mary's County, where Buddy Evans puts out his pots to catch blue crabs. Other days, he pulls up the pots and finds all the crabs dead inside. It's just like a fog. It rolls in, it rolls out," said Evans, a 37-year-old waterman from Smith Island.

What Evans and others call "bad water" has been robbed by algae of its dissolved oxygen, which fish and crabs need to breathe. Scientists blame man-made pollutants -- animal manure, suburban lawn-care products and treated sewage -- that act like underwater fertilizer for the algae.

For 20 years, this kind of pollution has been recognized as the most pervasive of the Chesapeake's many troubles. But years of effort to curb it has made little change: Last summer, when heat and high rainfall made the algae bloom heavily, about 40 percent of bay water lacked adequate oxygen, according to the Environmental Protection Agency's Chesapeake Bay Program.

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The problem is blue-green algae, which have infested the river (ed. - the Potomac) this year in the highest concentrations in 20 years, according to the Maryland Department of Natural Resources. Unlike the algae that trouble the saltier Chesapeake Bay, these freshwater algae tend to float on the surface of the Potomac, forming a scum that resembles bright-green paint. "It just looks like a golf course out there, it's so green," Ken Penrod, another longtime Potomac bass guide, said in a telephone interview. The algae can be toxic. Any concentration of algae exceeding 10,000 cells per milliliter can be harmful to some aquatic life, scientists said. This year, the Potomac has had concentrations as high as 80 million cells per milliliter. Earlier this summer, Maryland officials warned against drinking or swimming in algae-filled water, and the river town of Colonial Beach, Va., had to shut its beaches when a large bloom appeared there."

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http://www.washingtonpost.com/wp-dyn/articles/A3624-2004Aug15.html

Long but very interesting article.