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Armada of Stinky Seaweed Blobs Heading Straight for Florida Beaches

“The Great Atlantic Sargassum Belt” has broken a record as it approaches the shoreline. Prepare for “inevitable” clumps of seaweed on South Florida beaches.

FLORIDA — The looming mass of sargassum (seaweed) approaching South Florida beaches has now officially broken a record. The 5,000-mile-wide blob has been formally named “The Great Atlantic Sargassum Belt” and reached a record estimate of 13 million tons as of March 31.

The University of South Florida’s Optical Oceanography Lab has been monitoring the sargassum belt via satellite as it approaches the shore. In their latest sargassum bulletin, researchers said the February estimate was low because of “persistent cloud cover in the eastern Atlantic” blocking their satellites’ sea view.

The sargassum bloom as of March 2023. Red areas have a higher density of seaweed. (University of South Florida Optical Oceanography Laboratory)

Dr. Chuanmin Hu and his colleagues also emphasized that the sargassum belt isn’t one giant mass of uninterrupted seaweed but an accumulation of “clumps and mats scattered randomly within the 5,000-mile sargassum belt.”

Some coastal cities, including Fort Lauderdale and Boca Raton, have large blobs of the smelly, slimy seaweed approaching just offshore.

“Major beaching events are inevitable around the Caribbean, along the ocean side of the Florida Keys and east coast of Florida, although the exact timings and locations are difficult to predict,” USF researchers wrote in the monthly sargassum bulletin.

The South Florida seaweed season generally runs from May to October, with June and July as the peak. Sargassum on its own is harmless to humans, but it does trap sea lice, jellyfish and other critters that can irritate the skin. In addition, as it decomposes in the sun, it releases hydrogen sulfide that can aggravate respiratory conditions and make the beach smell like rotten eggs.

Currently, there are three main strategies for managing seaweed. State parks leave it on the beach to naturally decay. Most large cities remove it with bulldozers and dispose of it in landfills. But some researchers are exploring ways to convert the nutrient-rich sargassum into “ecoal,” a type of charcoal used for cooking fuel.