The summer heat continues to contribute to blue-green algae blooms across Florida …
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The summer heat continues to contribute to blue-green algae blooms across Florida. Lack of water movement also increases the likelihood of algal blooms. While blue-green algal blooms have been reported on Lake Okeechobee, samples collected recently are below the level considered safe for recreational contact (swimming).
In an June 21 media briefing, Major Cory Bell, deputy commander of the U.S. Army Corps of Engineers Jacksonville District, the only water leaving Lake Okeechobee is via evapotranspiration. No lake water can be released south until the flood waters from the heavy rainfall the week of June 11-14 recedes. South of Lake Okeechobee, the Everglades Agricultural Area farms, stormwater treatment areas (STAs) and water conservation areas (WCAs) received about 15 inches of direct rainfall in just a few days – some areas received even more. The flood control system for the EAA can move about 3/4 inch of water per day.
No water will be released to the Caloosahatchee River unless local bain runoff is less than the target flow of 2,000 cubic feet per second (cfs) at the W. P. Franklin Lock, more than 43 miles from Moore Haven, where the lake meets the river.
No lake water has been released east to the C-44 canal (St. Lucie Canal) since April. After the recent storms, water from the C-44 canal backflowed into Lake O.
Cyanobacteria (commonly called blue-green algae) are part of the lake’s natural ecosystem. Most of the time they are not visible to the human eye. Under the right conditions – hot weather, lack of water movement and available phosphorus and nitrogen in the water – the microscopic cyanobacteria can reproduce rapidly into a visible “bloom.” According to the U.S. Geological Survey about 25% of the species of blue-green algae in the Lake Okeechobee Waterway are capable of producing toxins, but do not always produce toxins. The waterway includes the Caloosahatchee River, Lake Okeechobee, the St. Lucie Canal and the St. Lucie River.
The World Health Organization (WHO) and Environmental Protection Agency (EPA) consider microcystin toxin levels above 1.0 ppb to be unsafe for drinking water and levels above 8.0 ppb to be unsafe for human recreational contact (swimming).
Florida Department of Environmental Protection (FDEP) collects samples where algal blooms are reported. There were 55 reported site visits in the seven-day period ending June 20, with 55 samples collected. Algal bloom conditions were observed by samplers at 16 of the sites.
June 17-20, FDEP staff collected 14 Harmful Algal Bloom (HAB) response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name.
• Lake Okeechobee - Port Mayaca - Microcystis aeruginosa; no cyanotoxins detected.
• C-44 canal (St. Lucie Canal)- Microcystis aeruginosa; trace level [0.40 parts per billion (ppb)] microcystins detected.
• Doctors Lake - Wyndegate Drive: Microcystis aeruginosa; 1.9 ppb microcystins detected.
• Doctors Lake - End of Lawrence Road: Microcystis aeruginosa; trace level (0.78 ppb) microcystins detected.
• Lake Eustis - Center: Microcystis aeruginosa; no cyanotoxins detected.
• Unnamed Lake - off Sycamore Drive: No dominant algal taxon; no cyanotoxins detected.
• Lake Rowena - West Shore: Microcystis aeruginosa and Microcystis wesenbergii co-dominant; trace level (0.19 ppb) microcystins and 0.45 ppb cylindrospermopsin detected.
• Lake Gibson - West: Microcystis aeruginosa; trace level (0.46 ppb) microcystins and trace level (0.22 ppb) cylindrospermopsin detected.
• Crescent Lake - at Sunrise Park Boat Ramp: Microcystis aeruginosa; trace level (0.54 ppb) microcystins detected.
• Crescent Lake - Eagle Trail: Microcystis aeruginosa; trace level (0.12 ppb) microcystins detected.
• Lake Thonotosassa - Center: Microcystis aeruginosa and Botryococcus braunii co-dominant; 2.4 ppb microcystins detected.
• Caloosahatchee River - Alacante Canal North: No dominant algal taxon; no cyanotoxins detected.
• Caloosahatchee River - Rivers Condo: Microcystis aeruginosa; no cyanotoxins detected.
• C-17 Canal - Congress Avenue: Results pending.
In addition to FDEP sampling, South Florida Water Management District samples both reported bloom sites as well as routine monitoring sites.
June 13-19, SFWMD staff collected seven HAB response samples, four routine monitoring samples at water control structures (S77, S78, S79 and S80) and 29 Lake Okeechobee routine HAB monitoring samples (FEBIN, KISSR0.0, LZ2, NES191, L001, NES135, NCENTER, EASTSHORE, L004, L008, L005, POLESOUT3, POLESOUT2, POLESOUT1, POLESOUT, KBARSE, CLV10A, LZ40, L006, PALMOUT3, PALMOUT2, PALMOUT1, PALMOUT, LZ30, POLE3S, RITTAE2, LZ25A, L007 and PELBAY3). Dominant algal taxa and cyanotoxin results follow each waterbody name.
• Pahokee Marina: Microcystis aeruginosa; 1.8 ppb microcystins detected.
• S135LOCKDS: Microcystis aeruginosa; trace level (0.27 ppb) microcystins detected.
• S352: Algal results pending; no cyanotoxins detected.
• S351: Algal results pending; 4.7 ppb microcystins detected.
• S354: Algal results pending; 2.1 ppb microcystins detected.
• FEBIN: Microcystis aeruginosa and Raphidiopsis raciborskii co-dominant; no cyanotoxins detected.
• KISSR0.0: No dominant algal taxon; no cyanotoxins detected.
• LZ2: Dolichospermum circinale; no cyanotoxins detected.
• NES191: Microcystis aeruginosa; no cyanotoxins detected.
• L001: Microcystis aeruginosa; no cyanotoxins detected.
• NES135: No dominant algal taxon; trace level (0.49 ppb) microcystins detected.
• NCENTER: No dominant algal taxon; no cyanotoxins detected.
• EASTSHORE: No dominant algal taxon; no cyanotoxins detected.
• L004: Microcystis aeruginosa; no cyanotoxins detected.
• L008: No dominant algal taxon; trace level (0.35 ppb) microcystins detected.
• L005: Microcystis aeruginosa and Dolichospermum circinale co-dominant; no cyanotoxins detected.
• POLESOUT3: No dominant algal taxon; no cyanotoxins detected.
• POLESOUT2: Microcystis aeruginosa; no cyanotoxins detected.
• POLESOUT1: Microcystis aeruginosa; no cyanotoxins detected.
• POLESOUT: Microcystis aeruginosa and Planktolyngbya limnetica co-dominant; no cyanotoxins detected.
• KBARSE: Microcystis aeruginosa; no cyanotoxins detected.
• CLV10A: No dominant algal taxon; no cyanotoxins detected.
• LZ40: No dominant algal taxon; no cyanotoxins detected.
• C43 canal (Caloosahatchee River) - S77 (Julian Keen Jr. Lock, upstream): Microcystis aeruginosa and Raphidiopsis raciborskii co-dominant; no cyanotoxins detected.
• C43 canal - S78 (Ortona Lock, upstream): No dominant algal taxon; no cyanotoxins detected.
• C43 canal - S79 (W.P. Franklin Lock, upstream): No dominant algal taxon; no cyanotoxins detected.
• C44 canal (St. Lucie Canal) - S80 (St. Lucie Lock, upstream): No dominant algal taxon; no cyanotoxins detected.
• L-47 Canal - S135LOCKUS: No dominant algal taxon; no cyanotoxins detected.
• L8 Canal (Palm Beach County) - CULV10A: Algal results pending; no cyanotoxins detected.
