Cyanobacteria bloom lessens in Lake Okeechobee

OKEECHOBEE — The cyanobacteria bloom on Lake Okeechobee continues to be present in about 345 square miles of the Big O, but the density has decreased, according to the computer imagery taken by the National Oceanographic and Atmospheric Administration on Oct. 25.

The image shows cyanobacteria (also known as “blue-green algae”) in about 63 percent of Lake Okeechobee. About a dozen types of cyanobacteria are present in the lake year round; a few types are capable of producing toxins. The NOAA imagery does not indicate which types of cyanobacteria are present. The NOAA imagery does not indicate if any toxins are present.

Cyanobacteria on Lake Okeechobee, Oct. 25, 2018 as shown with NOAA imagery.

The colors in the image show the density of the cyanobacteria. Areas in red are the highest density and the most likely area to see visible surface scum. However, the satellite can detect cyanobacteria in the water column, so the cyanobacteria can be present when it is not visible to the boaters on the surface.

In addition to cyanobacteria, the lake’s ecosystem is also home to many types of algae.

The casual observer cannot tell what type of cyanobacteria and/or algae is present by looking at what appears to be an algal bloom. Florida Department of Environmental Protection (FDEP) takes water samples to examine the cyanobacteria and/or algae under a microscope and run tests to determine if toxins are present.

Cyanobacteria, although called “blue-green algae” is not technically algae. Cyanobacteria are photoautotrophic bacteria; they carry out photosynthesis and release oxygen.

Cyanobacteria do not have a nucleus. Algae are simple plants; algae have a nucleus.

When an algae bloom is reported, FDEP takes water samples to test for toxins. In the past 30 days, there have been only four reports of algae on Lake Okeechobee, and water sampled from Lake Okeechobee has indicated no toxins or very low levels of toxins. The World Health Organization (WHO) considers anything under 10 micrograms per liter of the toxin microcystin safe for recreational contact.

• A sample taken by FDEP near the center of the lake on Oct. 16 found mixed algae. Total microcystin was 0.29 micrograms per liter.

• A sample taken Oct. 8 on the lake near Moore Haven found mixed algae. No toxins were present.

• A sample taken Oct. 16 on the lake near Port Mayaca found mixed algae with microcystin levels at 0.31

• A sample taken Oct. 17 on the lake near Clewiston found mixed algae. No toxins were present.

To report a bloom, call the toll-free hotline at 855-305-3903.

Publisher/Editor Katrina Elsken can be reached at kelsken@newszap.com

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