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Algae worse than red tide

Publicized in: Bradenton Herald
Publication Date: May 6, 2007
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While 'red tide' has become a household word, not as much attention has been given to a growing problem in Florida - harmful blooms of blue-green algae in warm, stagnant fresh waters.

These primitive, one-celled organisms can cover entire ponds and lakes with thick green mats. But worse than the pollution and unsightliness is their release of strong and even deadly toxins - more poisonous than cobra venom.

'These are some of the most potent toxins we know of,' said Kenneth Hudnell, expert on freshwater algae blooms for the Environmental Protection Agency.

The freshwater blue-green algae were the subject of a workshop Saturday in Sarasota, sponsored by the Sarasota Department of Health and the Sierra Club, and featuring federal, state and local specialists on the subject.

A lot is still unknown about the many species of blue-green algae, said Hudnell. What is known is what a major encounter with their toxins can do. One type destroys the liver and another - a neurotoxin - causes muscle paralysis and eventual suffocation. More frequently the toxins cause skin rashes, respiratory, stomach and intestinal problems.

The main way Floridians come into contact with the toxins is by swimming in contaminated waters, said Andrew Reich, coordinator of the Aquatic Toxins Program for the Florida Department of Health. The toxins are also ingested by eating fish or shellfish from contaminated waters, and breathing the toxins that escape into the air as droplets.

Reich said there are no federal standards for acceptable levels of the toxins in water supplies. However, illness from from the algae - formally known as cyanobacteria - in public water supplies has been avoided through water treatment.

The organisms occur all over the state, and massive blooms have occurred in central and eastern Florida. One during the summer of 2005 covered the St. Johns River for 100 miles. It was called 'the Green Monster.'

Preventing blooms works better than trying to get rid of one that already exists, said Reich. Killing the organisms increases the amount of toxins in the water, because when they die, the cells release all their toxins, which persist, he said.

What causes these blooms? Both experts said they happen when conditions are right for the algae: Sunlight, temperature, slow-moving waters and nutrients from fertilizer runoff.

'While there is some uncertainty in their role in red tide,' said Hudnell, 'there is no controversy about the role of nutrients in cyanobacteria blooms.'

At a glance

What: Blooms of blue-green algae, called cyanobacteria. Does not include 'red tide,' which is caused by a different organism.

Problems: Releases toxins that are poisonous to humans, animals and plants; also causes degradation of water quality, fish kills.

Conditions for intensive blooms: Warm, stagnant waters; sunlight, nutrients

Control: Preventing nutrients from fertilizers, animal waste and sewage treatment discharges from entering surface waters.

What's next: Local government ordinances controlling the chemical composition and application of fertilizers. Newly created state task force to recommend basic statewide rules.

To report blooms or illnesses: (888) 232-8635

think about this...

"We must build a peace in South Florida - a peace between the people and their place, between the natural environment and man-made settlement, between the works of man and the life of mankind itself. "
~ Florida Gov. Reubin Askew ~