No, Florida is not getting smothered by a giant seaweed blob

Getting into the weeds on the sargassum media hype

Mats of Sargassum are nothing new. WJXT Meteorologist Mark Collins holds sargassum seaweed that washed up in Ft. Lauderdale back in 2019.

You have surely stepped on a common seaweed found on our beaches called sargassum. It’s not, nor will it be much of a problem locally in contrast to the Caribbean where currents pile it several feet high on the shore.

The beneficial macroalgae have floated in the oceans forever serving as a refuge for sea turtle hatchlings while providing food and habitat for marine life.

Yet too much of a good thing is bad. Over the last decade, sargassum has proliferated causing many environmental problems including a hit to tourist economies when tons of floating mats wash ashore on Caribbean beaches.

The amount of sargassum in the central Atlantic reached the second-highest February level since 2018 but there are reasons why it won’t be any more consequential than in past years for the Sunshine State.

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Since 2011, it has grown into a continuous belt of sargassum reaching from west Africa to the Gulf of Mexico. The annual density begins increasing early in the year and recurrently peaks around July.

A google trend search shows a blitz of media attention this month latching onto overstated viral headlines of seaweed blobs en route to Florida beaches.

March 2023 spike in on Google search trends for Sargassum Seaweed spiked higher than any other time in history.

Scientists’ concerns are toned down.

Near the hall from where I previously worked at the University of South Florida College of Marine Science, is a lab devoted to tracking sargassum algae using NASA satellite imagery.

The team pioneered an algae index and provides monthly updates on sargassum trends.

What’s puzzling is how the current bloom has decreased in size during February when it typically increases. This reversal comes after it doubled every month from November to January.

Researchers integrate surface currents to predict short-term sargassum movement and the main drivers are not aimed at Florida.

The prediction is for a banner year in the Caribbean Sea but perhaps not as large as previously feared early in the year according to the USF March bulletin. The oceanographers state the Florida Keys may start to see only small amounts according to the report.

Brighter colors on the floating algae index detect floating algae and other materials on the ocean surface.

Beach forecasts are just as routine as weather forecasts for the Lesser Antilles which bear the brunt of the seaweed beaching events before it drifts into the Caribbean Sea.

Saint Martin’s latest prediction for the island expects a mass of sargassum in the central Atlantic to move towards the North of the Antilles arc. This is a typical route into the historical great Sargasso Sea.

Eddies that swirl out from the Sargasso Sea can bring in rafts of seaweed to Duval and St. Johns counties. Southeast winds also result in carpets of washed-up sargasso which is typically thicker in south Florida where the Gulf Stream flows just miles from shore.


About the Author:

After covering the weather from every corner of Florida and doing marine research in the Gulf, Mark Collins settled in Jacksonville to forecast weather for The First Coast.