Algae bloom causes concerns

Posted 6/12/19

TALLAHASSEE — Florida’s new algae task force will meet today, just in time to discuss the latest round of algal blooms.

The Florida Department of Environmental Protection will host the …

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Algae bloom causes concerns


TALLAHASSEE — Florida’s new algae task force will meet today, just in time to discuss the latest round of algal blooms.

The Florida Department of Environmental Protection will host the inaugural meeting of the Blue-Green Algae Task Force, on June 12 at 10 a.m. in Tallahassee. The meeting will be livestreamed on the Florida Public Service Commission’s website, The Florida Channel, online at The key focus of this task force is to support funding and restoration initiatives, such as prioritizing solutions and making recommendations to expedite nutrient reductions in Lake Okeechobee and the downstream estuaries. During the first meeting, the task force will cover their charge, goals, roles of state and federal agencies in addressing algal issues, and state water management and water quality regulatory structure.

Special to the Lake Okeechobee News
The fishing on Lake Okeechobee has been phenomenal this year, according to Mike Krause of Okeechobee Fishing Headquarters, who shared this photo on June 6.

The hot summer weather and water levels below 11 feet (above sea level) have set the stage for algal blooms in Lake Okeechobee. Since the start of May, the Florida DEP has been sampling water from various locations in the lake. Until last week, the samples from the lake showed no toxins or extremely low levels of toxins.

Thanks to many years of studies by the University of Florida, scientists know the lake is home to about a dozen types of cyanobacteria, commonly referred to as “blue-green algae” (although it is not a true algae). Only a few species of the cyanobacteria found in the lake are capable of producing toxins. Those that can produce toxins do not always do so. Cyanobacteria, the oldest life form on the planet, is found all over the world.

A sample from an algae bloom on Lake Okeechobee in Palm Beach County waters about 10 miles southwest of Port Mayaca on June 5 tested positive for microcystin at a level of 17.6 micrograms per liter, according to the Florida Department of Environmental Protection. That is double the new EPA recommendation of 8 micrograms per liter as safe for recreational human contact. (The World Health Organization standard is 10 micrograms per liter.)

A water sample also taken on June 5 closer to Port Mayaca found no toxins in the water near a bloom of “mixed algae” there.

Samples taken elsewhere on the lake this summer have tested with no toxins or extremely low levels of toxins (2 micrograms per liter or less). Just because there was algae in a certain area on one day does not mean it will be there the next day. Boaters who check the National Oceanic and Atmospheric Administration (NOAA) imagery for blue-green algae bloom indications often can’t find any algae in areas where the map indicates algae should be found.

Lake Okeechobee covers more than 730 square miles. According to scientists who study algae, just because a bloom on one side of a lake or pond contains toxins does not mean toxins will be found elsewhere on the lake. That’s true even for a small pond. The aptly named “big water” is 40 miles across.

So, what does all this mean? It means one sample from an area with a visible algae bloom on June 5 had levels that indicate people should not swim in that area of the lake on that day (as in recreational contact). For most boaters, that’s not a problem. Lake Okeechobee is not a “swimming lake,” as most lake area residents have a healthy respect for the alligators. It also means FDEP will continue to monitor the situation and sample water to see what happens next.

Are fish from an area with a visible algae bloom safe to eat? Because there is really no way to tell by just looking at the algae, the Florida Department of Health advises against eating fish caught in an area with a visible algae bloom. That does not necessarily mean there is a problem with the fish. It means they advise to err on the side of caution.

“People shouldn’t panic,” said Mike Krause of Okeechobee Fishing Headquarters. “It’s a 730-square-mile lake. We’ve had one reading that was above the safe recreational level. I wouldn’t worry too much about that until there is a whole lot more to go on.”

Mr. Krause said the fishing on Lake Okeechobee has been phenomenal this summer, but advised anglers to go with a guide who is familiar with the lake. With Lake Okeechobee’s water level so low, it’s important to go out with someone who really knows the underwater topography of the big lake, he cautioned.

The Okeechobee Utility Authority, which uses water from Lake Okeechobee as the primary source of drinking water for the City of Okeechobee, is ready with its own testing, water treatment and backup plans. OUA pumps about 2.5 million gallons a day from Lake Okeechobee. The water pumps at the Clif Betts Jr. Lakeside Recreation Area (Lock 7) draw water from pipes that run out about 100 feet from shore. OUA staffers watch the water intake areas for any sign of algal blooms, according to OUA Executive Director John Hayford. They also watch for signs of algae in the water by sight and smell and periodically test for microcystins. Microcystin tests are not among the water quality tests required by the Environmental Protection Agency (EPA). The tests are an added precaution. If toxins were to be detected, he explained, OUA would switch to their backup plan, pumping water from the Rim Canal and from wells. The surface water plant treats water from Lake Okeechobee by coagulation, filtration, ozonation and chloramines for disinfection. The ozone takes out the color, turbidity and odor, and has the added benefit that it inactivates toxins. The EPA publication “Cyanobacteria and Cyanotoxins: Information for Drinking Water Systems” states that ozone is “very effective for oxidizing extracellular microcystin, anatoxin-a and cylindrospermopsin.”

On Tuesday, Mr. Hayford said OUA recently sampled the water for algae and is awaiting the results. He said OUA is also concerned about the effect of chemical spraying for aquatic invasive plants in Lake Okeechobee. “We have heard that they will be spraying in the lake near the intakes within the next few weeks,” he said. “They were asked to give us a call prior to spraying so that we can switch to the Rim Canal pump station. When they spray, the OUA is planning on sampling before and after and specifically testing for glyphosate.”

According to the U.S. Army Corps of Engineers, last week, the seven-day average flow into the lake from the north was 3,249 cubic feet per second (cfs). Flows to the Caloosahatchee at Moore Haven averaged 613 cfs. Flows at the Franklin Locks were 500 cfs (which means some water was lost in the 43 miles between Moore Haven and the Franklin Locks). From the east, water backflowed into Lake Okeechobee from Port Mayaca at an average rate of 45 cfs. No water flowed through the St. Lucie Lock. An average of 2,636 cfs flowed south.