Smack in the middle of the Florida peninsula, Lake Okeechobee, one of the largest lakes in the U.S., has a nagging problem. Nearly every year now, large blooms of algae form in the lake.
On a recent visit, even Steve Davis, a senior ecologist with the Everglades Foundation, was surprised.
"Oh my gosh," he exclaimed, "look how thick this blue-green mat is right here."
Lake Okeechobee is the source of much of the water that flows south through the Everglades. A recent NASA photo showed that this summer, as much as 90 percent of the lake's surface was covered with algae. At this lock, connecting the lake with the St. Lucie River, everything is coated in green.
"It's a pretty dense mat of, I would bet, microcystis blue-green algae," Davis says. "It looks like a paint truck crashed and spilled green paint all over the surface."
The algae have a strong smell that can irritate eyes and throats. Even worse, it can be toxic. Two years ago, algae flowing down the St. Lucie River from the lake forced the closure of beaches during the normally-packed July 4 holiday.
Algal blooms have long been a headache in Lake Okeechobee. For decades, nutrient-rich runoff from cattle ranches, farms, and sugar plantations has flowed into the lake.
"So that's really deposited a layer of phosphorus-rich muck on the bottom of the lake that in combination with the polluted surface waters makes for ripe conditions, especially this time of year for algae," Davis says.
From China to Kenya to Canada, when the weather turns warm, mats of bright green algae form in rivers and lakes, hurting local economies, causing fish kills and endangering water supplies. Phosphorus-rich runoff from farms, cities and suburbs have made algal blooms a perennial problem. The Everglades Foundation in South Florida, decided to tackle it head-on. https://www.npr.org/2018/07/06/626601088/figure-out-how-to-cheaply-fix-algae-blooms-and-win-10-million