The culprit? Red tide. As defined by the Florida Fish and Wildlife Research Institute (FWRI), the phenomenon is a higher-than-normal concentration of a microscopic, plantlike organism called Karenia brevis. The organism produces a toxin that can affect the central nervous system of fish. At high concentrations (called a bloom), the organisms may discolor the water and cause respiratory difficulties in humans.
"Red tide toxin will make you sick," says Bob Rigby, a passionate crusader for cleaning up Florida's inland and offshore waters. For the past 11 years, Rigby, 66, has been working on developing a chemical compound to control the organism that causes red tide.
Rigby, former owner of a heavy-equipment construction company and inventor of a machine that cleans gutters and removes roadway pollutants, admits that he doesn't have a scientific education. But he's come up with a chemical concoction he says will kill the organism. It takes about a drop to treat one gallon of water, he says.
"My intent is to treat it offshore where the bloom develops -- kill it there," he says.
Although red tide has been found worldwide, the Florida type is found only in the Gulf of Mexico. Blooms found off Florida's Atlantic Coast most likely originated in the Gulf and were carried by the Gulf Stream currents around the peninsula.
When Rigby, who lives in Nokomis, couldn't get local marine research laboratories to test the compound, he turned to nearby Venice High School. With the help of the FWRI, which provided samples of the red tide organism, and two grants of $1,000 each from the Venice City Council, the high school students have been testing Rigby's formula.
So far, the young researchers have found Rigby's formula -- which he won't explain in detail because of intellectual property concerns -- to be effective in very small concentrations in killing the red tide organism. They've also found that it won't harm fish. And what about the formula's effect on humans? It hasn't been tested, but Rigby quips, "I've bathed in it before."
Scientists at more established venues are also studying red tide. Researchers at Sarasota's Mote Marine Laboratory have filed a patent application for controlling the growth of algae blooms generated by Karenia brevis by applying seawater containing low levels of dissolved ozone directly onto or under the surface of water containing the blooms. And FWRI is conducting an in-depth study of Karenia brevis' occurrence and dispersal as well as a volunteer monitoring project.
RED TIDE INFORMATION : redtideonline.com
The Red Tide Alliance website has links to the current status of red tide blooms in Florida and historical maps of red tide activity. There are also health tips and a red tide information kit designed to help businesses explain red tide to tourists and other customers. The alliance is a public-private partnership of the Florida Fish and Wildlife Research Institute in St. Petersburg, Sarasota's Mote Marine Laboratory and Solutions to Avoid Red Tide (START), a grass-roots citizens organization.