January 11, 2007

Possible Cause of Fish Kills Found

WASHINGTON (AP) - After more than seven years of study scientists have isolated a toxin that they say may have killed millions of fish along the East Coast in the 1990s.

The fish kills were associated with a parasitic algae called Pfiesteria, but until now researchers have been unable to determine how the organism killed the fish.

Peter Moeller, a chemist with the National Oceanic and Atmospheric Administration, said Thursday that he was able to isolate a toxin from Pfiesteria, but that the poison lasted only a few days and was destroyed by light.

That would explain why researchers detected poisons sometimes but not other times.

Moeller had to use red light in his lab at NOAA's Center for Coastal Environmental Health in Charleston, S.C. His findings are being published in the journal Environmental Science and Technology.

Researchers have disagreed about whether Pfiesteria produces a poison, and Moeller said the rapid breakdown of the chemical is probably the reason some have been unable to isolate it in the past.

Moeller said the poison incorporates iron and copper. "Copper is toxic to most organisms," he said.

In the lab Pfiesteria is producing a chemical that is toxic to sheepshead minnows, Moeller said, and now that needs to be confirmed in the wild.

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