This Sargassum was first reported by
Christopher Columbus in the 15th century but recently appeared in 2011 in the Atlantic.[4]
As of 2023, the belt is estimated to weigh about 5.5 million metric tonnes and extends 5,000 miles (8,000 km), stretching from
West Africa to the
Gulf of Mexico.[5][6]
“I try to shy away from the term blob. That’s not really what it is,” says Barnes, who says that the Great Atlantic Sargassum Belt is really a series of many small blobs with individual patches that are as large as an acre. Smushed together, he adds, it would be roughly the size of
Delaware.
Due to the smell, the attracted insects, and the sheer amount of it piling up on beaches, the Sargassum Belt has a negative impact on communities in the Caribbean, and West Africa.[7] When the Sargassum dies after about 48 hours on land, it releases
hydrogen sulfide, a toxic gas. The sulfide can irritate eyes, nose and throat and has a smell akin to that of rotting eggs.[8] The sulfide also can affect people with respiratory problems, including asthma.[9] In 2022, the largest bloom on record was recorded, causing
Guadeloupe to issue a health alert, as well as the
US Virgin Islands issuing a state of emergency, requesting help from
FEMA.[citation needed]
The buildup of Sargassum is caused by nutrients flowing into the Atlantic from water discharged by the
Amazon and
upwelling currents off West Africa. The Sargassum Belt, while in the
Sargasso Sea, is different, composed of different
morphological types of Sargassum. The Sargassum Belt has also been found to possess lower
biodiversity than the Sargasso Sea and is mainly composed of more highly nutrient-efficient organisms.[12]