Gulf of Mexico
Ron Arwood / Caloosa Waterkeeper

FL - Here, there, everywhere: Red tide plagues SWFL after Hurricane Ian

Red tide is blooming along coastlines from Sarasota to Collier counties, and while scientists have yet to discover what kick-starts a red tide blooms, research has proven heavy rains, storm surge, and flooding from tropical storms like Hurricane Ian on Sept. 28, 2022, wash nutrient-rich water back into the Gulf of Mexico, which can "feed" existing blooms and make them stronger, bigger, and last longer

Florida Department of Health officials in Manatee, Sarasota, Charlotte, Lee, and Collier counties are issuing health alerts daily warning of the real and present danger to human and animals.

Red tide is everywhere.

From Tampa Bay south to Ten Thousand Islands, local groups and state agencies that test for and track red tide are warning that the harmful algae that kills fish, sickens dogs, and whose acrid air chase people off the beach is here.

And there. And there. And there.

Red tide was detected at every beach in Sarasota County soon after Hurricane Ian made landfall near Fort Myers in late September. Earlier this month, the Florida Fish and Wildlife Conservation Commission found the red tide organism, Karenia brevis, in nearly 100 samples throughout Southwest Florida.

Florida Department of Health officials in Manatee, Sarasota, Charlotte, Lee, and Collier counties, taken as a group, are issuing health alerts daily warning of the real and present danger to human and animals.

The red tide is so prevalent, so pungent, and so potentially poisonous that the authors of the health advisories ignored the long-established practice of softening the language to avoid scaring away tourists.

“Stay away from the water,” a Charlotte County health advisory warned. “Do not swim in waters with dead fish. Wash your skin and clothing with soap and fresh water if you have had recent contact with red tide. Those with chronic respiratory problems should be especially cautious and stay away … as red tide can affect your breathing. Keep pets and livestock away and out of the water, sea foam and dead sea life. If your pet swims in waters with red tide, wash it as soon as possible. Do not harvest or eat molluscan shellfish or distressed or dead fish from this location. Residents may want to wear masks.”

There is a lot of not-so-quiet resignation in the seven weeks since Hurricane Ian that red tide would follow. Local charter captains and coastal environmental groups say anecdotal evidence is enough for them: the massive red tide that lasted from 2017 to 2019 followed hurricanes Irma and Maria.

And scientific evidence is mounting as well. A pair of otherwise unrelated research projects found that, while the organism that causes red tide is always present in the Gulf of Mexico, if nature decides it’s time for a bloom the influx of nutrient pollution “feeds” it, which allows the bloom to making it last longer and be stronger.

The ground scrubbing done by the massive amount of rain, storm surge, and flood waters from hurricanes like Ian washed a sick mess of pollutants into streams and rivers. Nitrogen and phosphorus from fertilizers; human waste from many of the region’s 100,000-plus antiquated septic systems that were inundated; animal feces; lawn clippings; it all flows from those streams and rivers into the bays that mix with the Gulf of Mexico.

Chemical processes between the saltwater and all the stuff in the runoff breaks things down into various microscopic nutrients that become a dominant feature of the seawater, where there is always background concentrations of K. brevis that can bloom into red tides when conditions are right.

 The runoff from Hurricane Ian into the Gulf of Mexico is clearly visible in this picture taken by a NASA satellite in space
NASA/The runoff from Hurricane Ian into the Gulf of Mexico is clearly visible in this picture taken by a NASA satellite in space

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