Inside Florida's Algae-Fueled Nightmare

The shape of things to come in U.S. politics could be decided, in no small part, by foul-smelling, fish-killing slime.

Florida is in the grips of an algae crisis of epic proportions. Pollution and water management issues have triggered bloom after bloom of blue-green algae on the ginormous Lake Okeechobee, the beating heart of the state’s water system. When water is released from the lake via drainage canals, the stinky, slimy gunk creeps into rivers and estuaries, mucking up coastlines and sickening residents.


Meanwhile, a separate algae outbreak—starring the saltwater-loving Karenia brevis—has laid siege to Florida’s southwest coast, killing tens of thousands of fish as well as manatees, sea turtles, and dolphins. The so-called red tide bloom currently spans some 135 miles of coastline, and it shows no signs of stopping.

Both blue-green algae and red tide are naturally-occurring organisms. But, as Earther learned when we traveled to Florida to speak with experts and see the blooms for ourselves, today’s algae crisis has human fingerprints all over it. It’s deeply intertwined with development, agriculture, and politics. Solving it will ultimately require a vast overhaul of how Florida moves and uses water—and a concession that the decision to tame and drain America’s largest swamp nearly a century ago carried some unintended consequences.


If one thing’s certain, it’s that Floridians are sick of algae, and its death-like stench will be fresh in folks’ memories as they head to the polls in November. Republican Governor Rick Scott is leaving his post to make a run at Democratic Senator Bill Nelson’s seat, and whoever wins could well decide the majority in the Senate. Both have blamed the other’s policies for the algae crisis.

Will a bunch of opportunistic microbes have an outsized voice this election season? Stranger things have happened in recent memory.



Maddie, this is awesome and huge kudos to you and the video production team.

One thing that is a bit more nuanced and hasn’t gotten much attention is that there are some potentially interesting interactions going on within Lake O. While the main issue is Microcystis blooms, there have been reports throughout the summer by FL SeaGrant (based, I believe, on FWC/FDEP sampling) that at least a couple times the bloom has actually switched back and forth between Anabaena and Microcystis dominance. Why does that matter? Well, like most microorganisms, Microcystis needs a “fixed” source of inorganic/organic nutrients to survive. Anabaena, however are nitrogen fixers meaning they are able to covert atmospheric N2 into bioavailable N. But this process can be leaky, so it’s not uncommon for lakes to see blooms those blooms lead to Microcystis dominance once they can capitalize on all that new, “fixed” nitrogen.

Lake O has historically had a phosphorus problem (which is the main reason why any water entering the Everglades is mandated to be much, much cleaner) because there’s virtually no biological mechanism for it to be removed permanently. It either gets “buried” in the sediments as they accrete or it gets resuspended and recycled over and over helping to fuel more blooms until they are flushed out to the coasts. And when phosphorus is high, nitrogen fixers like Anabaena are usually much more favored since they can essentially make their own nitrogen (in reality it’s a bit more complicated). But I think there’s indirect evidence to suggest that this seesawing between the different cyanobacteria may be helping to prolong that particular bloom...

As for the red tide, there’s a whole host of reasons why it could be as bad as it is this year as noted in the video. The Gulf of Mexico/coastal Florida is a much more open system relative to a lake, even one as big as Lake O, and trying to pinpoint the exact nutrient sources is a difficult task!