No End in Sight for Florida’s Algae Emergency as Red Tide Spreads up Atlantic Coast

An access point to a beach closed off in Palm Beach County due to red tide on October 2.
An access point to a beach closed off in Palm Beach County due to red tide on October 2.
Photo: AP

The red tide that’s plagued Florida’s Gulf Coast for a year and made a rare jump east earlier this month wasn’t vanquished by Hurricane Michael. Instead the toxic algae bloom has continued to move up the state’s Atlantic coast, befouling beaches and raising fears of a new ecological crisis should it become widespread in the Indian River Lagoon, one of the most biodiverse estuaries in North America.

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Red tide, a rusty-brown ooze caused by the neurotoxin-producing algae Karenia Brevis, is a frequent occurrence along Florida’s Gulf Coast—it washes ashore from the West Florida continental shelf and is sustained by local and manmade nutrients. But the 2018 bloom’s recent Atlantic coast tear has been unusual. The Florida Fish and Wildlife Conservation Commission first detected the algae on the east coast near Palm Beach County at the end of September after it followed the Gulf of Mexico loop current. Since then, it’s migrated northward into what’s known as Treasure Coast—comprising Martin, St. Lucie, Indian River counties—and even the southern part of Space Coast in Brevard County.

Conditions have, unfortunately, been welcoming. Throughout its journey the red tide has been killing fish, releasing noxious fumes, and prompting widespread beach closures.

“We’ve got warm nutrient rich waters on our coast right now, and the conditions are set up well to allow that algae to bloom,” Zack Jud, a marine biologist with the Florida Oceanographic Society located in Stuart, Florida, told Earther.

Recent measurements by Florida’s Fish and Wildlife Commission have revealed patches of algae off Treasure Coast at what’s considered “high” densities of over a million cells per liter of seawater. However, Jud noted that much lower concentrations, such as those seen off Stuart, can still kill fish and cause breathing problems for humans.

“Today, guests at our nature center are coughing and we’re a quarter mile from the ocean,” Jud said of conditions on Monday.

His biggest concern is the Indian River Lagoon, a 156-mile long estuary complex that traces Florida’s Atlantic coastline from north of Cape Canaveral to Jupiter Inlet. So far, red tide has only been detected in isolated patches within the lagoon and at fairly low concentrations. But favorable salinity levels combined with loads of manmade nutrients could trigger a more widespread bloom of red tide.

That, Jud said, would be “absolutely devastating to our economy and ecology.”

While the Indian River Lagoon is regularly inundated with blooms of blue-green and brown algae that choke out fish by gobbling up oxygen, K. brevis’s toxins pose an additional deadly threat to dolphins, manatees, and other animals that make their home there. A widespread, red tide-induced die-off is unlikely, but Jud said it’s not inconceivable.

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“When you have a confined body of water like the Indian river lagoon—156 miles long but only 1-2 miles wide—[it] would not be impossible to experience very extensive losses of marine organisms,” he continued.

There’s no telling how long the red tide will stick around on the Atlantic coast. National Oceanic and Atmospheric Administration oceanographer Richard Stump told Earther that while previous east coast blooms have been fairly short lived and winter wind patterns could help push the bloom offshore, “we don’t have a whole lot to go on.”

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While there are no quick fixes that will make red tides go away now or in the future, Jud said anything that can be done to minimize the level of nutrients making their way into coastal estuaries could help stave off a crisis. In addition to receiving nutrient-rich discharges from Florida’s Lake Okeechobee, local fertilizer use, leaky septic tanks and inadequate sewage all help fill the Indian River Lagoon with algae fuel.

“Individual homeowners can make a difference,” Jud said. “We don’t need bright green grass that’s gonna cost us the health of our estuary.”

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Correction: An earlier version of this article described Zack Jud as an oceanographer. He is actually a marine biologist. The text has been updated to reflect this. A clause has also been added to the second to last paragraph to emphasize that there are no quick fixes for the red tide.

Maddie Stone is a freelancer based in Philadelphia.

DISCUSSION

TinaBelcher'sBuns

Since the IRL is a very restricted lagoon, there’s only a few spots where a truly marine phytoplankton like K. brevis can enter. And based on current sampling map it seems like the only spot within the lagoon proper is way down by the St. Lucie inlet. The Indian River is a misnomer as water essentially flows within the lagoon based on prevailing winds. So to me it’s unlikely that it spreads north in the lagoon much further, but the St. Lucie section of the estuary has already been hit hard with the cyanobacteria (largely Microcystis) released from Lake O, so not great news for those residents!

However, I would suspect the Ft. Pierce and Sebastian inlets are also of major concern right now given the more dense patches found along the beaches in that area. What also would concern me would be if it gets all the way up past Cocoa and into the Port Canaveral inlet. The northern IRL, especially the Banana River, have essentially acted like incubators for large blooms of estuarine species over the last several years. In the north we’ve had everything from the green/cyanobacteria “Superbloom” in 2011, to subsequent brown tides (Aureoumbra lagunensis) and even some red tides (not K. brevis though, usually Pyrodinium which can be toxic too) in between. A big part of this is, ironically, the lack flushing as turnover times are sometime 150+ days in the north. So once something gets in, it’s really hard for it to leave if nutrient, lights, etc. conditions are favorable. Maybe a threat of K. brevis invasion will stop people from suggesting we just add more inlets to the lagoon as a way to combat blooms...