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It will take more than a hurricane to shake Florida’s red tide

It will take more than a hurricane to shake Florida’s red tide


The harmful algae bloom continues

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Red Tide Warnings Have Closed Some Miami Area Beaches
Photo by Joe Raedle/Getty Images

Even a hurricane isn’t powerful enough to dislodge a toxic algal bloom from Florida’s shores. When Hurricane Michael pummeled the Florida panhandle last week, scientists wondered whether the storm would finally shake loose the red tide clinging to the state’s coastline. The harmful algal bloom has been killing off fish and releasing plumes of neurotoxins for months  — and even after enduring surging seas and winds of up to 155 miles per hour, it doesn’t seem to be going anywhere.

Before Michael hit, experts speculated the bloom could play out in a few different ways: the storm could break up the bloom, make it worse, or a combination of both. Now, with Florida recovering from Hurricane Michael and the dregs of Hurricane Willa on schedule to drop one to two inches of rain on the Florida panhandle over the next few days, the verdict is in: the bloom continues, as Earther first reported. “The general scientific consensus is that Michael had no effect on the red tide,” Tracy Fanara, an environmental engineer at Mote Marine Laboratory in Sarasota, Florida, says in a text message to The Verge.

“Michael had no effect.”

Florida red tides are an overgrowth of a type of algae called Karenia brevis, which produces a neurotoxin that can be deadly to marine creatures and irritating to the eyes and lungs of people on land. Red tides originate miles offshore, and can be carried closer to the coast on ocean currents. There, if conditions are right, they thrive — turning into a toxic flotilla that tends to appear in the late summer or fall and disappear in the winter, according to the National Oceanic and Atmospheric Administration. This particular red tide, however, has stuck around around for about a year, which NOAA says is unusual.

After the storm, Fanara says that people continued to report irritated lungs and dead fish in parts of the Panhandle. The bloom persisted on Florida’s east coast as well, she says. The west coast of Florida got a brief break as offshore winds blew the bloom-tainted water away from shore — but it’s back now, says Bob Weisberg, a professor of physical oceanography at the University of South Florida. “As far as the red tide goes, Michael’s been out of the picture,” he says. “What little respite we had was for a day or two.”

And as for the rain due from the remains of what was once Hurricane Willa, Weisberg doesn’t expect to see much of an effect. “Rain is rain. It’s not the cause of red tide,” Weisberg says. And it’s unlikely to end the red tide either. What will? “That’s still a mystery,” he says.