Scientists say climate change will worsen these algae problems


Floating on oxygen molecules in a mucus-like blob, microcystis is most content in lazy water warmed to 86 degrees.

Add sunlight to stimulate photosynthesis and nutrients for food, and — boom — it blooms.

The single-cell organism, a type of cyanobacteria — more commonly known as blue-green algae — produces the toxin microcystin, which has been found in dangerously high levels in the St. Lucie and Caloosahatchee estuaries this summer. The scary levels have raised safety fears among residents and created talking points for political candidates racing to the source to show people they care.

And, scientists believe, because of climate change, these harmful algae blooms will worsen.

And South Florida has all the ingredients for the freshwater scourge.

“Lake Okeechobee has the perfect recipe for making blooms,” said Karl Havens, director of Florida Sea Grant at the University of Florida. “But it’s not Mother Nature. The Florida Peninsula didn’t always have this problem.”

While a warming globe will mean more days with algae-friendly temperatures, South Florida also has the unique dilemma of decades of calamitous human manipulation to its natural plumbing system.

RELATED: Scott issues emergency order over blue-green algae

In an effort to more efficiently drain land for cattle and communities north of the lake, the Kissimmee River was deepened and straightened, funneling rain, along with heavy loads of phosphorous and nitrogen, straight into Lake Okeechobee. Previously, the river meandered for 103 miles through Central Florida, flowing more slowly and filtering through riparian marshes where nutrients could be pulled out by plants.

At the same time, decades of back-pumping from sugar growers — a practice since curtailed and heavily monitored — shot fertilizer-tainted water into the lake from the south.

The result was a buffet for cyanobacteria.

‘We will see more algae blooms with more warmth’

When lake water is discharged to the estuaries, as it has been periodically since June 1, the algae goes with it. The fresh lake water also dilutes the salinity in the brackish waterways, reducing their ability to fight algae growth. The discharges themselves are another man-made problem, created after Lake Okeechobee’s natural overflow south into the Everglades was diverted to put in farms and homes.

“They want calm, hot, high-nutrient water and away they’ll go,” said J. William Louda, a research professor at Florida Atlantic University’s department of chemistry, about the microcystis. “What it comes down to is we are fertilizing the Earth to death and we will see more algae blooms with more warmth.”

RELATED: White House approves massive reservoir to hold Lake O overflow

Air temperature globally has increased by about 1.8 degrees over the past 115 years, making the period between 1901 and 2016 the warmest in the history of modern civilization, according to the federal Climate Science Special Report released in November.

Under a worse-case-scenario, South Florida could see up to 70 more days per year of temperatures warmer than 90 degrees by the mid-21st Century, according to the report, which was overseen by the U.S. Global Change Research Program.

Higher temperatures mean increased bouts of drenching rains because warm air holds more moisture, and there will be higher evaporation rates of lakes and oceans.

Today, the Kissimmee is being restored to its former ramble, and back-pumping of agricultural runoff into Lake Okeechobee is a rare event undertaken only if there is a threat of flooding.

But Havens said it’s estimated that the watershed north of Lake Okeechobee contains enough nutrients from past agricultural activities to fuel high nitrogen and phosphorous inputs for the next 50 years, even if farming stopped today.

The lake bed also is laden with “legacy” nutrients accumulated from decades past that can be stirred up and suspended in the water column by high winds.

“That happened with Hurricane Irma,” said Brian LaPointe, an FAU research professor and algae expert. “Fertilizers and septic tanks are the two biggest sources of nitrogen pollution to surface waters in Florida, and both of these must be mitigated if we are to reduce harmful algae blooms in the future.”

RELATED: Editorial: Long-term plan to fix algae blooms needs Big Sugar backing

The algae does more than just foul waterways with a kale smoothie-like goop. It can cause serious health problems, including liver failure if people swim in or drink toxin-laden water. Rashes, respiratory problems, and nausea also are linked to toxic algae.

A health advisory was issued Wednesday by the Martin County Health Department for the area of Phipps Park in Stuart where toxin levels were found in the “high” range for health problems. But the test results can take three to five days.

“Residents are put at risk over the weekends while the Florida Department of Health waits on results from the Florida Department of Environmental Protection,” said John Cassani, whose group Calusa Waterkeeper is a member of the national nonprofit Waterkeeper Alliance. “Seemingly no real strategy on (DEP’s) part.”

Professor: Some don’t want to believe ‘man can change the environment’

Satellite images from the National Oceanic and Atmospheric Administration estimated 90 percent of the 730-square-mile Lake Okeechobee was infected with cyanobacteria on July 2.

But the blooms can grow exponentially, and then die quickly. On June 12, just 1 percent of the lake had cyanobacteria.

More recent images have been obscured by clouds or Lake Okeechobee was out of the satellite’s view, said Sachi Mishra, a satellite oceanographer with the National Centers for Coastal Ocean Science.

Col. Jason Kirk, the Army Corps’ Jacksonville District commander, said Thursday that restoration projects underway will make a “measurable improvement” in reducing the need for discharges from Lake Okeechobee in the next six to seven years. The Corps controls water levels in the lake.

Louda isn’t convinced that will fix the lake’s algae concerns.

“We have to get to the root cause of nutrient input and it has to be done sooner than later,” Louda said. “Some people don’t want to believe man can change the environment of Earth. Well, wake up people.”

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