A large blue-green algae bloom in Lake Okeechobee was found to contain a high level of toxins by the Florida Department of Environmental Protection as water releases from the lake more than double into the St. Lucie Estuary.
According to the Florida DEP, water sampled Monday from the lake at the Port Mayaca lock contained 24.4 micrograms per liter of the toxin microcystin.
The World Health Organization says 10 to 20 micrograms per liter is considered a moderate level, with 20 to 2,000 considered high.
On Monday, water sampled on the canal side of the Port Mayaca lock was found to have 5.1 micrograms per liter of microcystin, which is considered a low level. Of eight areas sampled since May 18, four were found to be toxin free.
“Although a majority of our testing shows very low toxins in the blue-green algae, we will continue to work with the South Florida Water Management District to monitor the algal blooms to keep Floridians and visitors informed and safe,” said Dee Ann Miller, of the DEP.
The area with the highest level was on the lake side of the Port Mayaca lock.
Miller said the area is non-recreational.
“We have shared these results with the Corps and the Florida Department of Health,” she said.
Concerns about how the algal bloom will impact the ecosystems of the St. Lucie and Caloosahatchee estuaries heightened Thursday when the U.S. Army Corps of Engineers announced it would increase discharges from the lake.
Beginning today, 1.1 billion gallons of freshwater per day will be released from Lake Okeechobee into the St. Lucie River. That’s an increase from 420 million gallons per day.
The Caloosahatchee Estuary will get 2.5 billion gallons per day, up from 1.2 billion gallons per day.
The corps monitors the level of Lake Okeechobee closely because if it gets too high, it could begin to erode the Herbert Hoover Dike, which protects communities around the lake from flooding. The corps likes to keep the lake between 12.5 feet and 15.5 feet above sea level.
On Thursday, the lake was at 14.38 feet, close to a May 2010 high mark of 14.57 feet. Last year, the lake was at 12.65 feet above sea level on June 1.
Lt. Col. Jennifer Reynolds, who is the Corps’ deputy district commander for South Florida, said she can’t predict how the algae bloom will be affected by the increase in lake discharges.
There is a chance that the algae will be disrupted by turbulence in the water created by the discharges, she said.
“They grow better in fresh water conditions, but turbulent water tends to suppress their reproduction rate so we’re not entirely sure what is going to happen,” Reynolds said Thursday. “Where blooms will appear and become problematic, we don’t have a good way to predict that.”