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Did Helene and Milton spark Florida’s red tide?

Can hurricanes cause a red tide? Not exactly

FILE PHOTO - Red tide season usually lasts from October to around February, but the current red tide has stayed along the coast for around 10 months, killing massive amounts of fish as well as sea turtles, manatees and a whale shark swimming in the area. Photo by Joe Raedle/Getty Images

Red tide is surfacing once more along the immediate west coast of Florida. Shortly after major Hurricane Helene ripped north into the Big Bend of Florida, there were signs of a burst in algal activity starting to appear. Milton more or less sealed the deal.

Statewide concentrations map (Florida Fish and Wildlife)

What is red tide? For those of you who aren’t aware, it is a dramatic surge in algae producing “phytoplankton” that causes exponential vegetation growth that would otherwise be much more gradual. Phytoplankton form one of the lowest pieces of the natural food chain in any body of water.

Another way to describe a red tide, is a Harmful Algae Bloom (HAB for those who enjoy acronyms). When these blooms grow beyond a certain point, they can be seen by the naked eye and even by satellite! They take on a look of red when looked upon from above the surface of the water. In large concentrations, they can harm the rest of the ecosystem within it is growing. In extreme cases, they can start to kill off other animal and sea life, even going as far as affecting us humans.

There are toxic and non-toxic forms of algae producing organisms. Both can still contribute to the death of aquatic wildlife and pose negative impacts to folks who tread into algae-stricken waters. Red Tide can cause physical ailments such as skin irritation and burning eyes. When the huge surge of algae begins to wither away, they tend to release toxins that can cause coughing, sneezing, runny nose, wheezing, and shortness of breath, according to the Florida Department of Health.

So, did Helene and Milton actually cause this latest surge in our Florida red tide? While they directly contributed to the increase in algal growth, hurricanes do not in fact cause a red tide in of themselves.

Tropical cyclones thrive on warm ocean water. It’s the fuel to their tropical internal combustion engine. As such, the storm surge, the wind, the rain, all act to stir the oceanic pot beneath them.

Sea surface temperature anomaly (WKMG)

Because of this stirring effect, it helps bring nutrient-rich water into favorable settings to start producing algal growth unlike the traditional tempo would favor. This is called upwelling, precisely what occurs to reduce sea surface temperatures after a hurricane moves through. The same effect is what causes the sudden rise in phytoplankton that then go on to create the harmful algae blooms we know as Red Tide.

West Florida especially was faced with several bouts of severe storm surge and coastal flooding even dating back to Hurricane Debby’s arrival in early August. This was a pre-cursor to what Helene and Milton finished by once more turning over the Gulf of Mexico waters along our coast.

Thankfully, according to Florida Fish and Wildlife, the red tide organism they monitor to detect what level of red tide is currently observed is found at low concentrations along the coast, especially closest to Sarasota, Manatee, and Pinellas counties where Milton specifically made landfall.

Southwest FL Milton landfall site concentrations of algae producers (Florida Fish and Wildlife)

However further water sampling is needed. Because of the pace with which Florida was impact by both hurricanes, sampling has been delayed and will pick back up in the near distant future.


About the Author
David Nazario headshot

David joined WKMG-TV and ClickOrlando.com in September 2024.