OKEECHOBEE -- As the summer heat wave continues, cyanobacteria can be found in nearly 90 percent of the big lake, according to the National Oceanic and Atmospheric Administration.

Cyanobacteria, commonly called “blue green algae,” -- although it is not actually algae -- sometimes produces toxins. So far, Florida Department of Environmental Protection tests have shown only very low levels of toxins around the bloom areas in Lake Okeechobee. More samples were taken on Monday.

Cyanobacteria that can produce toxins does not always do so.

Oceanographer Michelle Tomlinson of the NOAA National Ocean Service explained they have been monitoring satellite photos of the lake since the start of June.

"The algorithm we developed for the imagery is showing cyanobacteria blooms," she explained. “So it is separating out the cyanobacteria from any other background algae in the lake. There may be some non-harmful phytoplankton mixed in there but what you are seeing is the concentration of the cyanobacteria.”

According to Dee Ann Miller of the Florida Department of Health, “Some – not all – blue-green algae can produce toxins that can contribute to environmental problems and affect public health. Little is known about exactly what environmental conditions trigger toxin production. Over time, these toxins are diluted and eventually break down and disappear. Persistent blooms are routinely monitored and retested. Because you cannot tell if algae is producing toxins by looking at it, the Florida Department of Environmental Protection (DEP) coordinates with the water management districts and the Florida Fish and Wildlife Conservation Commission to routinely sample observed and reported algal blooms and test for algal identification and toxin levels.”

A sample taken near Port Mayaca on June 25 had 2.2 micrograms per liter of the toxin, microcystin. A sample taken the same day near Moore Haven had 3.3 micrograms per liter of microcystin.

The World Health Organization considers level above 10 micrograms per liter to be hazardous for recreational contact.

More water samples were taken on Monday, July 2. According to FDEP, it takes about four days for testing to determine the type or types of algae and/or cyanobacteria present, and the toxin levels if any.

No fish kills have been reported in the lake this summer.






The NOAA images, however, do not reflect what boaters and fishermen see on the lake. From many areas of the shoreline, no algae is visible.