Almost Half of Florida Water Bodies Have Algal Blooms, and Climate Change Is Worsening the Problem

Ninety percent of Lake Okeechobee was covered in cyanobacteria in the summer of 2018.
Ninety percent of Lake Okeechobee was covered in cyanobacteria in the summer of 2018. Sentinel 2 satellite photo via Environmental Working Group
Florida — home of armed iguana hunters, exploding toilets, and the nation's grandparents — just so happens to be the perfect petri dish for algal blooms. Because blue-green algae absorb energy from the sun and quickly grow in warm freshwater, the Sunshine State offers optimal conditions for the microorganisms called cyanobacteria to thrive.

Nearly all of Lake Okeechobee was covered in cyanobacteria in 2018, and the bacteria has returned this summer. The Florida Department of Environmental Protection tested 108 bodies of water statewide in the past month, and 44 percent had algal blooms. Eight sites were tested in Broward County in the past two weeks. Algal blooms were found in all but one.

"We have a problem," says Soren Rundquist, the director of spatial analysis for the nonprofit Environmental Working Group. "Florida's warmer climate is naturally conducive to algal blooms."

Federal and state tests have found cyanobacteria toxins in hundreds of bodies of water in the United States, according to a new report issued today by the Environmental Working Group. The analysis warns that current water-testing regulations are not nearly enough to keep citizens safe from the toxins in their water.

Not all algal blooms are harmful, but the dominant type of cyanobacteria found in Lake Okeechobee is toxic. It can produce both neurotoxins and hepatoxins, causing health effects ranging from mild (headaches and sore throats) to severe (tumor formations and cancer).

Unfortunately, Florida's algae problem is expected to worsen with climate change. Rundquist says algal bloom season is already beginning earlier and lasting longer.

"Florida is an area in which we'll see more severe and more frequent algal blooms," he says.

Increased rainfall due to a changing climate means more agricultural runoff into Florida waters as well. Nutrients commonly found in fertilizer include phosphorus and nitrogen, which have been found to support algal blooms as they grow and propagate. Florida is home to one of the largest phosphate mines in the world, and the chemical can also be found in animal waste and septic systems.

"Those conditions exacerbate the growth of toxic algae outbreaks," Rundquist says. "It offers ideal growing conditions and creates more opportunities for these neurotoxins to form."

Surprisingly, Florida is one of the more progressive states in its response to algal blooms. It is one of 20 states that track blooms and one of 14 that has recent publicly available data. There's even a hotline for Floridians to call if they see freshwater or saltwater blooms. Still, Rundquist would like to see more aggressive year-round testing.

"The ephemeral nature of toxic algae requires weekly or at minimum bimonthly testing of beaches," he says. "Once a year isn't going to cut it in terms of alerting the general public to this toxic bacteria."

The Environmental Protection Agency has placed several cyanotoxins on its list of regulated water contaminants under the Safe Drinking Water Act, but a new policy could still be years away. Currently, the agency tests freshwater quality every five years. The results from 2007 and 2012 were included in the Environmental Working Group's report, but the 2017 results have not been made public yet.
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