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Blue-green algae update

By: Author Bob Rountree

Posted on Last updated:

Weekly Update from the Florida Department of Environmental Protection (DEP)

Sept. 8 – Sept. 14, 2023 – There were 36 reported site visits in the past seven days with 36 samples collected. Algal bloom conditions were observed by samplers at 17 of the sites.

Satellite imagery from 9/14 for Lake Okeechobee shows low to moderate bloom potential on approximately 20% of the lake, primarily in the northwest quadrant. 

Satellite imagery from 9/14 for the Caloosahatchee and St. Lucie estuaries shows no visible bloom potential. 

Satellite imagery from 9/14 for the St. Johns River shows low to moderate bloom potential on approximately 30% of Lake George, extending down the mainstem of the river to Clarks Creek. 

Please keep in mind that bloom potential is subject to change due to rapidly changing environmental conditions or satellite inconsistencies (i.e., wind, rain, temperature or stage.)

Blue-green algae detail

On 9/11- 9/14, Florida Department of Environmental Protection (DEP) staff collected 17 harmful algal bloom (HAB) response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

• Lake Rowena – Near NE Corner: Microcystis aeruginosa; trace level (0.22 parts per billion [ppb]) cylindrospermopsin detected.

• Lake Yale – Near Center: Microcystis aeruginosa; trace level (0.24 ppb) cylindrospermopsin detected.

• Ortega River – 0.3 Miles up Morven Canal: No dominant algal taxon; no cyanotoxins detected.

• Lake Okeechobee – 1 Mile NW of Pahokee: No dominant algal taxon; no cyanotoxins detected.

• Lake Okeechobee – S308C (lakeside): Microcystis aeruginosa; no cyanotoxins detected.

• C44 Canal – S308C (canal side): No dominant algal taxon; no cyanotoxins detected.

• Lake Howell – N Shore: Microcystis aeruginosa; trace level (0.15 ppb) cylindrospermopsin detected.

• Lake Haines – Boat Ramp: Microcystis wesenbergii and Planktolyngbya limnetica; trace levels of microcystins (0.26 ppb) and cylindrospermopsin (0.51 ppb).

• Lake Rochelle – Dock: Microcystis aeruginosa; no cyanotoxins detected.

• Lake Placid: Microcystis aeruginosa and Microcystis wesenbergii; no cyanotoxins detected.

• Lake Weohyakapka – W Boat Ramp: No dominant algal taxon; no cyanotoxins detected.

• Tiger Lake – Center: Microcystis aeruginosa and Microcystis wesenbergii; trace level (0.12 ppb) microcystins detected.

Results are pending for Caloosahatchee – Raleigh Canal; Lake George – North; Little Half Moon Lake – South; Lake Worrell – Ridge Rd.; and Georges Lake – Boat Ramp.

On 9/14, South Florida Water Management District staff collected HAB response samples at C44 Canal – Timer Powers Park; Lake Okeechobee -S354; Lake Okeechobee -S352; L8 Canal – CULV10A; and Lake Okeechobee- S271. Results are pending.

On 9/12-9/14, St. Johns River Water Management District staff collected five HAB response and nine HAB routine samples.

• St. Johns River – Shands Bridge: No dominant algal taxon; no cyanotoxins detected.

• Doctors Lake – Salt Myrtle Lane: Microcystis wesenbergii; no cyanotoxins detected.

• Doctors Lake – Pace Island Dock: Microcystis wesenbergii; no cyanotoxins detected.

• Doctors Lake – Center: No dominant algal taxon; no cyanotoxins detected.

• St. Johns River – Mandarin Point: No dominant algal taxon; no cyanotoxins detected.

• Stick Marsh – North: Microcystis aeruginosa; trace level (0.65 ppb) cylindrospermopsin detected.

• Lake George – Center: Planktolyngbya limnetica; trace level (0.16 ppb) cylindrospermopsin detected.

• Lake Yale: Microcystis aeruginosa; trace level (0.24 ppb) cylindrospermopsin detected.

• Lateral M Canal – Just North of Blue Cypress Lake: No dominant algal taxon; no cyanotoxins detected.

• Blue Cypress Lake – Center: No dominant algal taxon; no cyanotoxins detected.

Results are pending for Crescent Lake – Mouth of Dunns Creek (CRESLM); Crescent Lake – Mouth of Haw Creek; Lake Jesup – Center (OW-CTR); and Lake Monroe – Center (LMAC).

Pending Results from Last Week

On 9/7, Highlands County staff collected a HAB response sample at Lake Glenada – Boat Ramp. The co-dominant algal taxa were Microcystis aeruginosa and Microcystis wesenbergii and a trace level (0.49 ppb) of microcystins was detected. 

Results for completed analyses are available at FloridaDEP.gov/AlgalBloom. 

Go here for Interactive Blue-Green Algae Map of the entire state

Results for completed analysis are available at FloridaDEP.gov/AlgalBloom.

blue-green algae
Blue-green algae bloom. (Photo courtesy St. Johns River Water Management District.)

Blue-Green Algae statewide dashboard — LIVE map prepared by the Florida Dept of Environmental Protection

More from Florida Rambler: The Florida Red Tide Report

Contributing factors to both red tide and blue-green algae.

blue-green algae site 1web final algae red tide inforgraphic Blue-green algae update
Contributing factors to both red tide and blue-green algae. (Florida Audubon)

Blue-green algae

In water bodies with blue-green algae, if people or animals splash or if boats create wakes, the cyanotoxins in the algae can release into the air. The toxins mix with water droplets and spray—that’s how people and animals can inhale the toxin. These toxins can’t pass through your skin easily so swallowing large amounts of contaminated water is what causes illness. This algae is blue, bright green, brown or red, and can have a strong odor like rotting plants. Pets can become sick from blue-green algae so keep them out of those areas and away from contaminated marine animals and fish.

SYMPTOMS? Stay away from blue-green algae.  For some people, blue-green algae can cause rashes, stomach cramps, nausea, diarrhea and vomiting. People who are very sensitive to smells can have respiratory irritation. Sometimes, high exposures of toxin can affect the liver and nervous system.
If you come into contact with blue-green algae, get out of the area and wash off with soap and water. See your doctor if you think blue-green algae has made you sick.

CONTAMINATED WATER. Water from areas with blue-green algae can make animals and people sick—stay away from these areas.

SWIMMING. Don’t swim in or around blue-green algae.

BLUE-GREEN ALGAE AND FISH.  Fish tested from water with blue-green algae show that cyanotoxins don’t accumulate much in the edible parts — muscle or fillet — of fish, but can in other organs. Rinse fish fillets with tap or bottled water. Throw out guts. Cook fish well.

blue-green algae
Blue-green algae update 5

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