Promising Treatment for Red Tide: Successful Open-Water Test in Gulf of Mexico

A group of experts from the University of Central Florida has conducted a successful open-water test using "clay flocculation" to reduce red tide in the Gulf of Mexico. Preliminary results are promising, with the technique showing potential.

Promising Treatment for Red Tide: Successful Open-Water Test in Gulf of Mexico
Red tide/Karenia brevis in Tamaulipas, 2015. Credit: Cofepris

A "promising" treatment for red tide, a harmful seasonal phenomenon in the Gulf of Mexico, has been successfully tested by a group of experts from the University of Central Florida. The trial, led by biologist and professor Kristy Lewis in conjunction with the Mote Marine Laboratory, is the first successful open-water test to reduce red tide, which frequently leads to the mass death of marine life.

The large-scale experiment took place between the end of February and the beginning of March in Sarasota Bay on the west coast of Florida. Using a technique called "clay flocculation", which involves the use of a specific type of clay, the researchers placed eight plastic tubes, each 6 feet (1.8 meters) wide, from the water's surface to the sea floor. Lewis described them as "giant test tubes". Preliminary results of the trial are "quite promising", according to Lewis, who spoke to the agency EFE.

Red Tide Treatment Test

The researchers used clay treated with a chemical compound to attract and sink the microorganism Karenia brevis responsible for Florida's red tide in four tubes. Water samples were collected to investigate what happens to the algal toxins when they fall to the ocean floor and whether they remain inactive or not. While the tests "reduce an immediate acute impact of red tide," the toxins are not released into the air, which causes respiratory and eye irritation.

The three-year-long tests began with laboratory tests and 20-liter tanks and then scaled up to larger environments, with the impact of the clay on invertebrates such as blue crabs, sea urchins, and clams also being tested to ensure that the cure is not worse than the disease.

Depending on the results of the samples, the next steps will be taken, with plans to investigate what happens when this treatment is used near seagrass beds and then distributed by the tide and currents. The researchers are confident that these tests could lead to a "mitigation strategy" for red tide, a phenomenon that cannot be prevented and poses a risk to human health due to the toxins released by fish killed by it.

Red tide impact on Florida

According to a study by the University of Miami, the recent major red tide event in 2018 resulted in a 61% decrease in all types of travel to Florida, causing millions of dollars in losses. Currently, the Florida Fish and Wildlife Conservation Commission (FWC) has issued a warning about the presence of red tide on the west coast of Florida, specifically in Pinellas, Sarasota, Charlotte, Hillsborough, Manatee, Collier, Lee, and lower Monroe counties. In the past 11 days, nearly 6,000 pounds of dead fish were removed from the waters in Indian Rocks Beach in Pinellas County alone, and another 3,000 pounds in Manatee County.

Moreover, experts anticipate a potential confluence of red tide and the sargassum phenomenon this year. The sargassum mass, which is up to 5,000 miles wide (about 8,000 kilometers), is moving across the Atlantic and could reach Florida's Gulf of Mexico coast. Lewis, a specialist in red tide at Florida Gulf Coast University, estimated that the combination of both phenomena could have a severe impact on Florida's tourism industry and marine life.