Drone video: Sargassum, a type of seaweed, takes over beaches
A record bloom of sargassum, a genus of seaweed, is possible this year, and its seen taking over Florida beaches.
The area of the Atlantic covered by seaweed set a new all-time record in April, a sign that could spell trouble for Florida beaches this summer.
In fact, scientists announced May 1 that the total amount of sargassum in the Atlantic in April was 40% higher than the previous all-time high set in June 2022, “which makes 2025 a new record year,” the University of South Florida Optical Oceanography Lab said in a statement.
“The big story is that the total amount has exceeded the previous all-time high,” University of South Florida oceanography professor Chuanmin Hu, who tracks sargassum movement, told USA TODAY. He said the annual high is typically in June or July.
He added that if history repeats itself, this year’s expanse of seaweed will continue to get bigger.
The exact reasons behind the record large mass still “need to be investigated,” the lab said. “Corresponding to these increases, sargassum beaching events have been reported around the Caribbean and along the southeast coast of Florida.”
Indeed, it was just last week that a mass of the weed washed ashore in Miami Beach.
Which beaches will be hit with the most seaweed? When will it land?
“Florida, as a whole, will no doubt see a lot more sargassum this summer from the Florida Keys to Jacksonville,” Hu said. “The impacts could be felt by late May and should last through the end of August and early September.”
Ultimately, though, the amount of seaweed that reaches Florida beaches will depend on ocean currents and wind patterns, which are “hard to predict.”
What is sargassum?
Sargassum is a yellowish-brown floating macroalgae that crabs, sea turtles, shrimp and other marine life depend on, but large amounts on beaches can scare off people — it has a reputation for being slimy and smelling bad as it rots. Some local Florida governments spend millions of dollars to clean it up.
About 31 million metric tons of sargassum was recorded between Africa and the Caribbean in April, according to Hu. That’s up from 14.5 million metric tons in March.
May sargassum forecast
As in most previous years, May is expected to see continued increases in most regions, the laboratory said.
“More sargassum is expected to be transported to the west Caribbean Sea and then to the Gulf through the Yucatan. Sargassum inundation will continue to occur in most of the Caribbean nations and islands as well as along the southeast coast of Florida.”
Sargassum reported by Columbus
According to the laboratory, sargassum in the Atlantic was first reported in 1492 by Christopher Columbus during his voyage in the North Atlantic Ocean, which possibly led to the name of Sargasso Sea, the only sea on Earth that has no physical boundary.
Before 2011, sargassum was mainly found in the Sargasso Sea and the Gulf of Mexico (renamed by the U.S. government as Gulf of America), although small amounts were also sighted in the Caribbean Sea and off the Brazilian coast.
The Great Atlantic Sargassum Belt
Although the Sargasso Sea and Gulf continued to show abundant sargassum, since 2011 most sargassum was found in a continuous “belt” in the tropical Atlantic extending from the west Africa to the Gulf, Hu said.
Because of the large scale (about 5,000 miles long) and high abundance of sargassum, the area was termed the Great Atlantic Sargassum Belt.
Contributing: Timothy O’Hara, Treasure Coast Newspapers
