Sargassum Season Is Back — and It Could Be the Worst Yet

South Florida beaches are bracing for what scientists warn may be a record-breaking sargassum year. The brown seaweed has already begun piling up along Miami-Dade and Broward county shorelines, earlier than in previous years.

Warmer ocean temperatures and elevated nutrient levels in the Atlantic are feeding unusually large blooms. Trade winds and currents push the floating algae from the Atlantic Sargassum Belt through the Caribbean and onto local beaches, where it decays and releases hydrogen sulfide gas — a sharp, rotten-egg odor that drives beachgoers away.

While sargassum supports marine ecosystems in the open ocean, massive beach accumulations hurt tourism and cost coastal communities millions in annual cleanup. With peak summer season approaching, officials are watching closely.