Algal blooms continue to be reported all over the state as the summer heat intensifies.
The Florida Department of Environmental Protection (FDEP) samples water bodies throughout the state where algal blooms are reported. In addition, South Florida Water Management District (SFWMD) routinely samples 28 sites on Lake Okeechobee every other week.
Not all algal blooms are harmful or toxic. About 25% of species of cyanobacteria species (commonly called blue-green algae) are capable of producing toxins. Those capable of producing toxins do not always do so. Laboratory tests are necessary to determine which species of algae and/or cyanobacteria are present and if any toxins are present.
The Environmental Protection Agency (EPA) considers microcystin levels below 1.0 parts per billion (ppb) to be safe for drinking water and levels below 8.0 ppb to be safe for human recreational contact (swimming).
When FDEP determines an algal bloom is a threat to human safety, they use algaecide to break up the bloom. For example, the Pahokee marina has been a hot spot for algal blooms for years. The design of the marina prevents little water flow and tests have shown higher levels of nitrogen at the marina than in the open lake. FDEP and SFWMD have treated algal blooms at the Pahokee marina several times this summer. On July 17, water sampled at the marina had microcystin toxins at 12 ppb. On July 26, water sampled from the marina had 6.5 ppb. On Aug. 1, the water sampled showed toxin levels of 1.4 ppb.
For the week of July 28-Aug. 3, the FDEP weekly report states there were 22 reported harmful algal bloom (HAB) response or HAB routine site visits in the past seven days statewide with 22 samples collected. Algal bloom conditions were observed by samplers at 17 of the sites.
The most recent usable satellite imagery for Lake Okeechobee from the most intense bloom potential in the northeastern quadrant of the lake.
Satellite imagery for the Caloosahatchee Estuary and the St. Lucie Estuary from Aug. 3 is partially obscured by cloud cover.
Satellite imagery for the St. Johns River from Aug. 3 is partially obscured by cloud cover and shows low to moderate bloom potential on approximately 35% of Lake George.
July 31-Aug. 3, FDEP staff collected 19 HAB response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name.
Results are pending for samples collected at Peace River - Brownville Park; Peace River - Veterans Park Ramp; and Peace River - Crews Park Boat Ramp.
On July 31, St. Johns River Water Management District (SJRWMD) collected one HAB response and one HAB routine sample.
On Aug. 3, Highlands County staff collected a HAB response sample from Lake Istokpoga. Results are pending.
Results are available for two HAB response samples collected on July 17 by DEP staff:
Results are available for three samples collected on July 27 by SJRWMD staff. Lake Monroe was HAB routine and the two Doctors Lake samples were HAB response.