Experts say even more seaweed will likely wash up on Florida’s beaches in 2025, predicting a “bumper” year for seaweed.
Researchers at the University of South Florida used satellite imagery to measure the monthly abundance of sargassum in the Atlantic Basin and found that December was an exceptionally high month of sargassum.
Ongoing research shows that Sagrasum abundance in the Gulf of Mexico, western Caribbean, and eastern Caribbean is currently low, which is normal for this time of year.
However, this was not the case in the Atlantic Ocean. In the Western Atlantic, sargassum has increased significantly since November, as a result of both local plants and seaweed migrating westward from the coast of Africa.
This band of seaweed spreads across the Atlantic Ocean each year, peaking in the summer, and drifting westward, often piling up on Caribbean islands or continuing into the Gulf of Mexico. From there, much of it travels around Florida and ends up congealing (and smelling) on East Coach beaches.
The study found that when compared to previous Decembers since 2011, sargassum abundance was above the 75th percentile for each region, meaning it was well above average and close to maximum. did.
The report said small amounts of sargassum had already reached the Lesser Antilles in the last week of December.
Sargassum growth typically increases after January and continues westward toward the United States. There aren’t that many in our area yet, but things could change. “Due to the relatively high abundance of sargassum in the tropical Atlantic,” the report says, “2025 is likely to be another big year for sargassum.”
The amount of sargassum has skyrocketed over the past 15 years, causing frustration for South Florida beachgoers and significant economic damage to the Caribbean region.
They support marine life in the open ocean, but when they decompose on shore they release hydrogen sulfide, a gas with an odor reminiscent of rotten eggs that can cause respiratory illnesses.
The reason for this sudden increase appears to be a phenomenon known as the Atlantic Sargassum Band (GASB). This is a massive, sometimes 5,000 mile wide sargassum bloom of the Atlantic Sargassum that did not exist until 2011.
This belt forms closer to the equator and farther north in the Atlantic Ocean than where sargassum historically formed.
A 2023 study by Florida Atlantic University’s Woods Hole Oceanographic Institution and others found that large blooms occur more frequently in Atlantic waters near the equator compared to waters farther north in the Sargasso Sea, where macroalgae have historically grown. associated with high concentrations of nutrients.
Finding higher levels of nutrients in the Atlantic Sargassum belt “provides conclusive evidence that GASB flooding is caused by nutrients,” said the study’s lead author Dennis McGillicuddy of Woods Hole. .
This article was originally published in Florida, a multi-newsroom initiative founded by the Miami Herald, South Florida Sun-Sentinel, Palm Beach Post, Orlando Sentinel, WLRN Public Media and the Tampa Bay Times. Produced in partnership with Climate Reporting Network.
