The Everglades Foundation has developed an early-warning system for red tide blooms in Southwest Florida, which has been able to forecast dangerous outbreaks of Karenia brevis with up to 84 percent accuracy.
The models use a machine-learning algorithm to crunch a large amount of real-time environmental data from red tide samples, satellite imagery of Florida’s west coast, ocean buoys, and river gauges to forecast the “worst” area, if any, expected across the greater Charlotte Harbor region during the following week, and a second forecast looks out four weeks
Red tide not only fouls the region’s beaches with decaying dead fish, it emits toxins that can trigger respiratory problems in humans. The poisons can also accumulate in shellfish, making them dangerous to eat.
Paul Julian is an aquatic ecologist with the foundation and a member of the team developing the warning system. He said, for now, their data will be shared with agencies doing public predictions of red tide and other algal bloom activity, such as the Florida Department of Environmental Protection and the South Florida Water Management Agency,
“Southwest Florida is linked to its environment, and so being able to understand when person X doesn't want to, say, go fishing tomorrow because red tides out there, and it's probably going to get worse, I think in the future, there's going to be multiple, multiple end users of the of it.
The foundation’s algorithm, developed with researchers from ECCO Scientific, takes into account samples as small as nitrate levels by the Franklin Locks on the Caloosahatchee River, to as large as the location of the Loop Current in the Gulf.
Red tides have been documented for more than a century, and the need for these types of reliable forecasting devices became a goal after severe outbreaks like one lasting from 2017 to 2019, Red tides can cause significant ecological and economic damage across Southwest Florida and typically show up at this time of year.
Red tide blooms first form offshore of Florida’s West Coast. Winds and tides can carry the bloom toward the shore where nutrient -rich waters along the coast can sustain, prolong, and intensify the blooms. The nutrients come from a variety of sources, often nutrient pollution when the water is filled with nitrogen and phosphorus.
The red tide organism produces a neurotoxin that kills fish and other marine wildlife. The toxin also presents public health risks: Eating shellfish contaminated by the neurotoxin can land you in the hospital, and when the neurotoxin gets into the air, it causes respiratory illness up to several kilometers inland from the coast.
The toxic effects extend beyond dead fish washing ashore. When waves break red tide cells, they release brevetoxins into the air, causing respiratory irritation several kilometers inland. The toxins also accumulate in shellfish, making them dangerous for human consumption.
The last red tide to affect Southwest Florida was abloom that began near Tampa Bay after Hurricane Milton in October 2024 and stretched from Tampa Bay o the Flo0rida Keys. At the time, Lee County health officials issued alerts for ten beach locations, including Sanibel, Captiva, and the Bonita Beach areas.
Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.
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