New Study May Reveal Toxic Trigger for Microbe

By Scott Harper, The Virginian-Pilot, Norfolk, Va.

Jan. 12–If full moons are to blame for werewolves, and strange elixirs create Mr. Hyde, what then turns a harmless microbe into “the cell from hell”?

It is a question that has baffled scientists since the 1990s, when the aquatic microbe called pfiesteria — pronounced “fee-steer-ee-ah” — emerged as an environmental threat and popular bogeyman along the East Coast.

In 1997, pfiesteria was blamed for killing millions of fish and sickening several people in coastal Virginia, North Carolina and Maryland. It frightened away seaside tourists and sunk seafood sales across the Mid-Atlantic.

Then, it large ly disappeared, igniting more scientific debate.

Like Dr. Jekyll or Lon Cheney’s Wolfman character, pfiesteria is usually harmless. It normally lives unseen and passively in muddy bottom sediments.

But something apparently trips its conversion into an aggressive, toxin-spewing predator, a switch that scientists have struggled to explain and pinpoint.

Is chicken manure the toxic trigger? Is it hog waste? Or maybe slow-moving water laden with nutrient pollution?

Or is pfiesteria toxic at all? Is it an over-hyped hoax?

On Thursday, a team of scientists released findings from a seven-year study that suggest two key truths about pfiesteria: The microbe can produce and release a lethal toxin, if only for short, sporadic periods; and the presence of heavy metals in waterways — especially copper — appears to be a prime culprit.

“We would observe toxic activity, and then it would disappear,” said Peter Moeller, an organic chemist with the National Oceanic and Atmospheric Administration, who oversaw the study.

Bright light also was a factor, Moeller said, and seemed to “excite” pfiesteria cells. He therefore doubts the microbe could “go toxic” at night.

To study the microbe’s mercurial biology, Moeller said researchers often were forced to work under red light, so as not to cause sudden changes.

The results support the controversial work of JoAnn Burkholder, a North Carolina State University researcher credited with discovering pfiesteria.

Her experiences — including how a colleague exposed to large amounts of the toxic microbes lost his memory — are featured in the book “And the Waters Turned to Blood.”

In a press release, Burkholder praised the NOAA research, saying “it’s like having a smoking gun.”

Critics have long said that pfiesteria research almost always takes place in a lab and therefore is unproven in the wild. The NOAA study, too, occurred in a lab.

In some trials, sheepshead minnows were immersed in dishes of water containing toxic pfiesteria cells. Moeller said the fish immediately “got very agitated” and would swim in circles or try to leap out of the dish. Nearly all of them died.

The research was published Thursday on the Web site Environmental Science and Technology Online News. A copy will appear in February in the peer-reviewed journal of the American Chemical Society.

Andrew Gordon, a toxicologist at Old Dominion University who has studied pfiesteria for years, said the NOAA research is valuable but will not resolve the debate about its dangers and biology.

“It gives us a paper tiger to test,” Gordon said in a statement.

— Reach Scott Harper at (757) 446-2340 or scott.harper@pilotonline.com.

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Copyright (c) 2007, The Virginian-Pilot, Norfolk, Va.

Distributed by McClatchy-Tribune Business News.

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