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Florida blue-green algae update

The U.S. Army Corp of Engineers began discharging water from Lake Okeechobee into the Caloosahatchee and St. Lucie estuaries in mid-February. These annual discharges are intended to manage lake levels ahead of Florida’s rainy season, and they often result in blue-green algae growth in coastal estuaries.

Related news:
  • Health alert issued for blue-green algal toxins in Lake Okeechobee, WPTV, March 16, 2024
  • Health Officials Issue Blue-Green Algae Bloom Alert for Dowling Lake North: Pasco County, FL – The Florida Department of Health in Pasco County has issued a Health Alert for the presence of harmful blue-green algal toxins in Dowling Lake-North. This is in response to a water sample taken on March 4, 2024. The public should exercise caution in and around Dowling Lake-North. Florida Department of Health, March 11

Latest blue-green algae sampling

Update from the Florida Department of Environmental Protection (DEP)

March 15 – March 21, 2024 – There were eight reported site visits in the past seven days with eight samples collected. Algal bloom conditions were observed by samplers at five of the sites.

Satellite imagery for Lake Okeechobee from 3/21 is partially obscured by cloud cover, but shows low to moderate bloom potential on approximately 15% – 20% of the lake, predominantly in the northwest quadrant of the lake, with more scattered bloom potential along the western, southern and eastern shorelines of the lake.

Satellite imagery for the Caloosahatchee Estuary from 3/21 shows scattered low to moderate bloom potential in the upper estuary. 

Satellite imagery for the St. Lucie Estuary from 3/21 shows no bloom potential on visible portions of the estuary. 

Satellite imagery for the St. Johns River from 3/21 shows scattered low to moderate bloom potential on Lake George and throughout the mainstem of the river from Lake George downstream to the city of Jacksonville. 

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.) 

On 3/20 – 3/21, Florida Department of Environmental Protection (DEP) staff collected five Harmful Algal Bloom (HAB) response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

Cherry Lake: Oedogonium sp.; no cyanotoxins detected.

Lake Pearl – Park Dock: Microcystis aeruginosa and Pseudanabaena mucicola; trace level [0.89 parts per billion (ppb)] microcystins detected.

Lake Minnehaha – East Dock: Microcystis aeruginosa; 0.80 ppb microcystins detected.

Blanton Lake – South Lobe: Results pending.

Lake Dowling – Off Dock: Results pending.

On 3/18, St. Johns River Water Management District (SJRWMD) collected one routine HAB monitoring sample at Lake Washington – Center: No dominant algal taxon; no cyanotoxins detected.

On 3/18, Highlands County staff collected two HAB response samples. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

Lake Placid – Boat Ramp: Microcystis wesenbergii and Cylindrospermopsis raciborskii; no cyanotoxins detected.

Lake Glenada – Boat Ramp: Microcystis aeruginosa and Microcystis wesenbergii; trace level (0.68 ppb) microcystins detected.

Last Week

On 3/14, DEP staff collected a HAB response sample from Lake Clarke Inflow – East Congress Avenue: No dominant algal taxon; no cyanotoxins detected.

On 3/13, South Florida Water Management District staff collected routine HAB monitoring samples at four locations on Lake Okeechobee. Dominant algal taxa and cyanotoxin results follow each waterbody name. 

CLV10A: No dominant algal taxon; no cyanotoxins detected.

PALMOUT: Microcystis aeruginosa; trace level (0.26 ppb) microcystins detected. 

LZ30: Microcystis aeruginosa; no cyanotoxins detected.

RITTAE2: Microcystis aeruginosa; no cyanotoxins detected.

On 3/14, SJRWMD staff collected a routine HAB monitoring sample at Crescent Lake – Mouth of Dunns Creek: No dominant algal taxon; no cyanotoxins detected.

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

Maps of blue-green algae test sites

The blue dots in the maps below represent positive samples within the past 30 days. The green dots represent tests over the past 90 days. For an interactive version of this map, which allows you to zoom in and read test results for specific test sites for the past 90 days, go to floridadep.gov/AlgalBloom

These maps were posted on March 22, 2024.

Caloosahatchee Estuary
blue-green algae caloiosahatchee Florida blue-green algae update
Florida blue-green algae update 12
Lake Okeechobee & St. Lucie Estuary
blue-green algae lake Florida blue-green algae update
Florida blue-green algae update 13
St. Johns River
blue-green algae stjohns Florida blue-green algae update
March 22, 2024 — The blue dots represent positive samples within the past 30 days. The green dots represent tests over the past 90 days. For an interactive version of this map, which allows you to zoom in and read test results for specific test sites for the past 90 days, go to 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 Florida 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
Florida blue-green algae update 14


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