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Ocean scientist suggest potential red tide cure may be worse than problem

Naples Daily News - Florida

15th April 2004

Donald Anderson has been on the trail of red tides all over the world for some 30 years. He is determined to find a way to tame them.

Anderson, a senior scientist at Woods Hole Oceanographic Institution in Massachusetts, reported progress Wednesday with experiments using clay to control red tide but warned that science has yet to overcome fears that the promising cure could be worse than the disease.

"We may be able to clear the way, but will society ever allow us to do this?” Anderson told almost 100 people at a breakfast lecture at the Port Royal Club in Naples.

Many people agree that red tide is a big problem. The blooms of microscopic toxic algae can poison shellfish and harm tourism. They trigger coughing fits in humans and litter beaches with dead fish. Red tide has been blamed for deaths of manatees, sea turtles and dolphins.

A red tide's worst enemy is proving to be phosphatic clay, a byproduct of the region's phosphate mining industry, laboratory studies show.

When sprayed into seawater, even in small amounts, tiny clay particles clump together, trap red tide cells and then sink to the ocean bottom.

Using clay to control red tides is a widespread practice in South Korea to protect the region's economically important fish farming industry.

In the United States, though, environmental regulators and some scientists eye such methods warily, Anderson said.

They fear unintended consequences to animals that live on the ocean bottom and worry about what will happen to the trapped red tide cells once they sink to the bottom.

Anderson said the trick is to find a balance.

"They've got to recognize that the ocean is no longer pristine," Anderson said. "We have been destroying our oceans."

The Florida Department of Environmental Protection approved a small field study by Mote Marine Laboratory in Sarasota Bay using clay to control red tide, but officials remain worried about the effects of larger-scale applications.

"Until we see the study results, we're not going to know that information," said Cece McKiernan, environmental administrator for the watershed and resource protection section in the DEP's office in Tampa.

Phosphatic clay contains phosphorus, an ingredient in fertilizers that can act as a pollutant by promoting algae growth.

Anderson said he doesn't expect any negative consequences from more phosphorus because there isn't enough nitrogen, another pollutant, in the water to create the reactions that would spur more algae growth.

Initial field tests in November 2003 didn't reveal any fatal flaw with spraying clay into a marine environment. Researchers now are waiting to test the process during an actual red tide.

"I just haven't seen a show-stopper here yet," Anderson said.

Last month, the Southwest Florida chapter of the Sierra Club criticized scientists for trying to find a way to control red tide instead of tracking down whether pollution from cities and farms is causing it.

Anderson said he's all for stemming polluted runoff into coastal waters but that red tide might not be a good poster child for pollution reduction.

"I think you put your neck out pretty far (by saying reducing pollution will solve red tide)," Anderson said.

Pollution reduction is a complex and costly proposition that could take decades and might end up not having much effect on red tide, Anderson said.

Research in other parts of the world seems to show a connection between toxic algae blooms and pollution.

Nutrient limits in Japan's Seto Inland Sea in 1974 have reduced the annual occurrence of red tides there from more than 300 to more than 100, according to a chart Anderson showed those attending Wednesday's session.

Another chart showed an upward trend in coastal red tides in China that coincided with increased fertilizer use.

Anderson said a global increase in nitrogen use has marine scientists around the world greatly concerned about marine waters, where it ends up.

Florida's west coast has its own place in the red tide world: no other coastal region in the world has red tides as frequently and as long-lasting as here, Anderson said.

"You have a rather special problem here and one I think we'll have with us for quite a while," he said.