Information related to Red Tide and Blue-Green algae blooms – SW Florida

This page is intended to be a resource to assist the Windsurfing community of SW Florida to better understand and be aware of the 2021 Red Tide and Blue-Green algae blooms. I will update this information on a regular basis but the focus will be to provide a single resource for trusted links to Government and Science based websites.

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Tampa Bay Waterkeeper

Tampa Bay Waterkeeper, a 501(c)3 non-profit organization, protects and improves the Tampa Bay watershed by combining sound science, policy advocacy, and grassroots community engagement to ensure swimmable, drinkable, and fishable water for all.

General Information via the Protecting Florida Together website

Red Tide

Red tide is one type of harmful algal bloom that is caused by high concentrations of toxic dinoflagellates, microscopic algae. In Florida and the Gulf of Mexico, the alga that causes most red tides is Karenia brevis, often abbreviated as K. brevis

At high enough concentrations, red tide can discolor water and give it a red or brown hue. Blooms caused by other algal species can also appear red or brown, but may also take on a green or purple coloration. Some algal blooms appear colorless. 

Red tides in Florida often develop in late summer and early fall with their point of origin typically 10-40 miles offshore. The initiation of any specific red tide event is difficult to predict, but once the algal bloom is located, the movement of the bloom may be forecast using wind information and water current data. Some blooms may be carried into shallow coastal waters, including bays and estuaries. However, K. brevis cannot tolerate prolonged exposure to low-salinity water and seldom penetrate the upper reaches of an estuary. 

If a red tide is transported by wind and currents to nearshore waters, the algae can use nutrients delivered from adjacent watersheds to fuel their growth and sustain the production of toxins with a broad range of negative impacts. Karenia brevis produces potent neurotoxins (brevetoxins) that can affect the health of both wildlife and people. For people, brevetoxins can cause respiratory irritation or illness if inhaled or neurotoxic shellfish poisoning if contaminated seafood is eaten.

Blue-Green Algae

Blue-green algae blooms occur primarily in freshwater water systems, whereas red tides tend to originate 10 – 40 miles offshore. Although wind and currents can push red tides into nearshore waters, including bays and estuaries, the algae that cause red tides cannot survive in freshwater systems