Parts of historic Everglades showing signs of blue-green algae with summer on the horizon

Chad Gillis
Fort Myers News-Press

Environmental groups and water quality experts are paying more attention to Lake Okeechobee as blue-green algae levels continue to spike in some areas of the system. 

The Florida Department of Environmental Protection reported elevated levels of microsystis in parts of the Lake Okeechobee and traces of the toxic bacteria in the upstream portion of the Caloosahatchee River. 

FDEP reports show microsystis also detected around the western edge of the lake and that 14 of 22 samples collected showed at least trace amounts of the toxins. 

"The  April 7 imagery was of pretty harsh cyanobacteria blooms," said Calusa Waterkeeper John Cassani. "There had been reports at Port Mayaca and a couple of other areas, and one of the recent lake samples came back with relatively high toxicity levels, above the recreational threshold." 

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Blue-green algae blooms can produce cyanobacteria, a toxic bacteria that can cause upset stomach and diarrhea in humans and even kill domestic animals in high doses. 

Researchers are still trying to determine the long-term impacts from exposure to blue-green algae but more and more studies are linking exposure to the algae with neurological disorders like Alzheimer's and ALS. 

Cyanobacteria is a neurotoxin that can also cause fish kills and create massive, thick matts of surface scum. 

They're common on Lake Okeechobee and can spread to coastal estuaries if conditions are right. 

Work continues on the Lake Okeechobee dike in Clewiston on Wednesday, March 31, 2021.

Florida Gulf Coast University researchers proved that the bacteria can become aerosolized and get into the airways and lungs of humans. 

DEP says the most recent satellite imagery shows increasing potential for low to moderate bloom conditions on the open lake. 

The April 15 satellite imagery of Lake Okeechobee from the National Oceanic and Atmospheric Administration, or NOAA, shows cyanobacteria blooming in the north part of the lake and on the southwest side, near Clewiston. 

The reports say wind and weather may obscure the imagery and cause an underestimation of algae. 

"The problem is you don’t see it at the surface because of the wave action and fetch, the area of the lake that is subject to wave energy," Cassani said. "So if you have a couple of calm days you’re probably going to see it back up at the surface."  

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The Caloosahatchee River and its estuary are polluted with excess nutrients, which can feed an algae bloom at any time. 

A bloom that started on Lake Okeechobee in the summer of 2018 spread down into the river and estuary and wreaked havoc on the Fort Myers-Cape Coral area. 

Algae mats thicker than carpet blanketed many local canals, and some residents had to flee their homes due to health concerns. 

Concentrations today are much lower than they were that summer, but they're still nearly three times higher than the U.S. Environmental Protection Agency's recommended exposure limits at some locations. 

"That’s pretty high, but at Port Mayaca there's a lot of that that builds up, kind of a backwater," said Barry Rosen, a professor at Florida Gulf Coast University's Water School. "If you stick a bottle in and collect them, you’re going to get a fairly high number. It’s not like it’s throughout the whole water column."

Rosen said the threat to the public is pretty minimal at this point. 

"It’s not toxic unless it’s consumed," Rosen said. "People just assume that it’s like Roundup that’s spilled in the water, but this stuff, you have to consume it. Does it get into the air? We’re trying to figure that out. Air moves around quite a bit, so we don’t know much of a dosage you get from air." 

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Rosen said he's more worried about the overall conditions of the system than low to moderate samples. 

"Of potential greater concern is does the water flow allow it to proliferate," Rosen said rhetorically. "Then you’re starting to fill edge to edge on the canals. Right now at Franklin Lock you’ll find it building up. Just keep your pets out of it. Pets get it on their fur and they clean themselves and they get a much higher concentration." 

Pets and other domestic animals can be more prone to blue-green toxicity because they may drink the water or ingest it while grooming themselves. 

Cassani said he worries the higher concentrations are coming, that they may already be in the river. 

"I was on the river (Thursday) morning and (Friday) at Franklin Lock (and Dam in Alva) and further down in the estuary, and the way I’m seeing it is it’s moving down in rivulets along the shore following the current downstream," Cassani said. "It’s definitely in the river and is becoming more frequent at the surface when it’s calm. It’s not a huge bloom but it’s there. The water looks really bad. It’ has a muddy brown look to it." 

This cyanobacteria, also called blue-green algae is seen blooming on the south shore of the Caloosahatchee River in Olga April 28, 2020. Calusa Waterkeeper John Cassani has identified nearby blooms as Microcystis, which produces dangerous toxins.

Rosen said blue-green algae blooms are becoming more of a problem everywhere. 

"They’re becoming more common and part of that is the climate is warming," Rosen said. "(Blue-green algae) like it warm. They are bacteria and they are equipped to be more productive than their neighbors. When things get warm, they’re going to do better." 

Connect with this reporter: @ChadEugene on Twitter.