Media, public panic, not Pfiesteria, seen as damaging bay Microscopic 'blooms' called common

September 26, 1997|By Frank D. Roylance | Frank D. Roylance,SUN STAFF Sun staff writer Timothy B. Wheeler contributed to this article.

Pfiesteria's biggest impact on people in the Chesapeake region may be an overheated press corps and public panic, according to scientists at a marine resource conference that began yesterday in Baltimore.

"Blooms" of microscopic phytoplankton such as Pfiesteria are normal, occur all over the world every year, and are "intrinsically beneficial to the food web process," said Dr. Sandra E. Shumway, of Long Island University. Only a tiny fraction -- perhaps 2 percent -- of those blooms involve species with toxic effects on fish, birds, marine mammals and people.

"I wouldn't make such a big deal of Pfiesteria if I wasn't here in the middle of it," she said. She complained that the public has been "whipped into a frenzy by the press," with potentially serious economic consequences for those in the region's seafood industry.

Shumway spoke at the opening session of the 1997 Science Conference of the International Council for Exploration of the Sea (ICES). As many as 600 scientists from 19 countries are gathering at the Stouffer's Renaissance Hotel to share the results of research in a wide variety of topics.

In Washington, Terry R. Garcia, acting assistant Commerce secretary, told a House subcommittee that harmful algae blooms are a concern because of the havoc they can wreak. Red and brown tides and shellfish poisonings in the U.S. have cost an estimated $1 billion to seafood and other industries in the past decade.

Visitors to the Columbus Center's Hall of Exploration can get the facts about Pfiesteria from maps; interactive video exhibits; the center's Internet Web page (; lectures and informal conversations with scientists and actual experiences in a laboratory.

No Pfiesteria have been brought to the lab. Dr. Carol Bossert, a molecular biologist at vice president for programming, said a "Level 3" isolation laboratory must be built to protect researchers from Pfiesteria's toxins.

When it is finished, visitors will be able to see the organism on video screens linked to microscopes in the lab, and observe scientists as they work to develop rapid testing methods for detecting Pfiesteria in local waters.

Dr. Katherine Richardson, coastal ecology research director at the Danish Institute for Fisheries Research, told the ICES gathering that Pfiesteria is just one of perhaps 4,000 species of tiny organisms known as phytoplankton.

"Their job is to convert the sun's energy into organic material," and their blooms provide a timely bonanza for creatures higher in the food chain.

Pfiesteria belongs to a sub-group called dinoflagellates, which propel themselves with a tiny hairlike tail.

Phytoplankton attract attention only when they bloom into large, visible masses and stain a beach, or when they begin to kill, she said. But of 4,000 known species, only 6 percent are responsible for such problems.

Only 2 percent -- fewer than 80 species -- are known to produce the toxins than have killed whales, dolphins and manatees in recent years. A toxic bloom in South Africa reportedly chased droves of lobsters up a beach.

In people, the toxins can cause skin rashes, cancers, memory loss, paralysis, diarrhea and death. Richardson said as many as 300 people are killed annually around the world as a result of eating shellfish that have concentrated the toxins.

Scientists don't know why the organisms produce the poisons, she said.

But there apparently is nothing new about it. Rock cores drilled in the Baltic region have revealed fossils suggesting that "red tide" blooms have been killing bivalves "for at least 150 million years," she said.

Seasonal blooms occur in temperate zones all over the world. A perception that they are increasing globally -- and that human pollution may be responsible -- may be the result of better reporting.

But Richardson said there is "very good evidence of a large increase in phytoplankton biomass and harmful algal blooms" in enclosed waters such as the South Kattegat near Denmark, and the Chesapeake Bay.

In those cases, the blooms may be fed by nutrients produced by human activity. Pesticides may be killing the creatures that eat harmful phytoplankton, and the discharge of ship ballast water may be introducing them in places where they didn't exist before.

Pub Date: 9/26/97

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