Algae red tides menace coastal seas Carolina's Neuse River shows stress

North Carolina's Neuse River shows heavy infestation


Like something out of a horror movie, the cell from hell attacks its victims in gruesome ways, frequently changing its body form with lightning speed. The unicellular organism, called Pfiesteria piscida, has at least 24 guises it can assume in the course of its lifetime. It can also masquerade as a plant or lie dormant for years in the absence of suitable prey.

Armed with a voracious appetite and vast reproductive powers, the microscopic animal moves through coastal waters to kill fish and shellfish by the millions and to poison anglers and others, producing pain, narcosis, disorientation, nausea, fatigue, vomiting, memory loss, immune failure and personality changes. Its toxins are so deadly that people who merely inhale its vapors can be hurt badly.

"This thing has us scared to death," said Rick Dove, the expert who has been appointed to keep track of the Neuse River in North Carolina, part of a coastal estuary where the organism periodically goes on killing sprees. "This river is our lifeblood. If it goes belly up, everything goes belly up."

Anything but a rare organism, Pfiesteria has scores of toxic cousins that appear to be multiplying around the globe, mainly as algae but sometimes as zooplankton and, most conspicuously, as red and brown tides.

In Chesapeake Bay

In the Chesapeake Bay, heavy inflows of freshwater this year already have led to record blooms of algae.

"I haven't seen anything like it," said Lawrence W. Harding Jr., an oceanographer with the University of Maryland who has been conducting aerial surveys of algae blooms in the bay since 1989. The algae blooms stretched to the Atlantic Ocean.

Record freshwater flows early this year coupled with snowmelt "loaded the bay up with nutrients," Harding said, producing some of the earliest and most extensive algae blooms he's seen.

"When we first began flying in March, we had red tides [algae] in and around the Bay Bridge and up toward the Patapsco River," he recalled. During spring, the midbay was clogged all the way to the Virginia capes with brownish blooms, he said.

Some ecologists believe there is a serious global epidemic of these marine microorganisms. They fear that their toxic tides may upset the natural balance of the oceans and are urging action to reduce the runoff of sewage and other nutritive substances that seem to promote the poisonous blooms. Other experts are more cautious, conceding that the number of reported incidents is up but withholding judgment on whether this is anything more than an upturn in a natural cycle, with more observers filing reports on the scourge.

A growing fear, intriguing but unconfirmed, is that nutrient runoff from human development, the heavy use of fertilizers and livestock farms is feeding the growth of the marauding swarms. If true, it bodes ill, given the global spread of the phosphorous and nitrogen from human sewage, animal waste and fertilizers that is increasingly polluting freshwater streams flowing into coastal estuaries.

"There's a correlation between increased nutrients in coastal waters and increased frequency of phytoplankton blooms," said Dr. Jane Lubchenco, a prominent ecologist at Oregon State University who studies the workings of the intertidal zone. "But that's not causation. It smells like it, but the evidence is skimpy."

More toxic than cyanide

Studies of the deadly blooms are accelerating, if only because the tiny killers have been found to harbor poisons 1,000 times more toxic than cyanide, strong enough to kill humans.

"People in Washington are beginning to realize that you can't attack this with Band-Aids," said Dr. Donald M. Anderson, of the Woods Hole Oceanographic Institution on Cape Cod, who is an expert on red tides. "Every single coastal state has this problem in one form or another.

"Everybody agrees that the impact and number of reported events are increasing," Anderson added. "At the very least, in many areas of the world we are adding nutrients in the form of pollution into coastal waters, and that seems to be producing more harmful blooms."

The suspicion is that natural cycles of bloom and bust are expanding into a global menace. For scientific sleuths, the challenge is to find clues that allow natural causes and cycles to be distinguished from ones that are altogether unnatural.

"The question is whether human effects are prompting an

increase in the frequency, virulence or the types of organisms," said Dr. Peter Franks, a red-tide expert at the Scripps Institution of Oceanography in La Jolla, Calif.

Red tides, he noted, are only occasionally red, also appearing as orange, brown and even green. And they never occur literally as tides, which are the rises and falls of the sea. The preferred

terms for the phenomena are harmful algal blooms (which kill things), noxious algal blooms (which smell bad) and exceptional algal blooms (which are visually striking but do no direct harm). Unfortunately, even nontoxic blooms can kill marine animals by depleting oxygen in the water.

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