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Red tide in Gulf of Mexico puts Florida Keys at risk

Researchers say toxin poses threat to coral reefs, fish

KEY LARGO, Fla. -- Scientists are tracking a 400-square-mile red tide that is drifting through the Gulf of Mexico and threatening to wash ashore on the Florida Keys.

"It's huge," said Billy Causey, superintendent of the Florida Keys National Marine Sanctuary, adding that the toxic tide poses "a major threat to coral and coral reefs."

Red tide is composed of a higher-than-normal concentration of microscopic algae that is toxic to fish and can cause watering and itching eyes in people, as well as coughing and sneezing.

It can also be dangerous for those with severe or chronic respiratory conditions. Swimmers who come into contact with it can develop an itchy rash, so its appearance forces beach closures. The sale of seafood caught within a red tide bloom is prohibited.

Lobsterman Gary Nichols is credited with spotting the tide Dec. 1, near the southwestern tip of Florida where the Shark River empties into the Gulf. He and his crew saw four dead dolphins floating in the algae, along with a large number of dead fish.

Nichols, a 40-year veteran of the crab and lobster trade off the Florida Keys, said the tide was the worst he had ever seen. It forced him to relocate 3,000 lobster and crab traps that were along its path.

"The water is usually a green-blue color, but the red tide turned it a dark brown with a red tint, and it smelled like dead fish," he said.

Chuanmin Hu, a scientist from the Florida Marine Research Institute, is using satellite imagery to track the tide, which he says seems to have joined another algae bloom emanating from the Shark River. The river algae, he said, is harmless, "but it may add additional fuel to the red tide." Red tide thrives on nutrients from dead fish and the river algae.

A predicted cold front with winds from the north could break the red tide apart, researchers said -- or push it closer to the Keys.

Eric Bartels of Florida State University's Mote Marine Laboratory, in the Keys, took water samples recently with the hope of predicting how the tide will behave.

"We're trying to learn as much as we can about red tide," he said. "The question we're trying to answer is if they are increasing in severity or coverage."

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