A raggedy carpet of vegetation recently surrounded an uninhabited island near the French Caribbean territory of St. Martin that is popular with tourists, forcing officials to suspend ferry service and cancel kayaking, paddleboarding and snorkeling tours. The normally translucent turquoise waters around Pinel Island turned into a prickly yellowish-brown slush.
Scientists say more research is needed to determine why sargassum levels in the region are so high, but the United Nations’ Caribbean Environment Program said possible factors include a rise in water temperatures as a result of climate change, and nitrogen-laden fertilizer and sewage that nourish the algae.
The concentration of algae is so heavy in parts of the eastern Caribbean that the French island of Guadeloupe issued a health alert in late July. It warned some communities about high levels of hydrogen sulfide gas emanating from the huge rotting clumps of seaweed. The gas, which smells like rotten eggs, can affect people with breathing problems such as asthma.
Lakes Beach is covered in sargassum in St. Andrew along the east coast of Barbados, Wednesday, July 27, 2022. More than 24 million tons of sargassum blanketed the Atlantic in June, up from 18.8 million tons in May, according to a monthly report published by the University of South Florida’s Optical Oceanography Lab that noted “a new historical record.
Masses of sargassum also have strangled the Caribbean’s fishing industry. It damages boat engines and fishing gear, prevents fishermen from reaching their vessels and fishing grounds and leads to a drop in the number of fish caught. Barbados, where the beaches are piled with reddish-brown seaweed, has been hit especially hard.