Science in the North Atlantic

Sargasso Seaa floating forest

It is the only sea on Earth bounded solely by currents: it lies at the centre of the Atlantic subtropical gyre, around Bermuda. It takes its name from sargassum, seaweed that lives and reproduces while floating in the open ocean, offering shelter to many marine species such as turtles and eels. Since 2011 a belt of sargassum has also been spreading across the tropical Atlantic, growing year after year: in 2025 it reached a record 37.5 million tonnes. For the fleet it is an obstacle: it gets caught on foils and rudders and slows the boats down. It is also a problem for the people of the Caribbean: it piles up on the coasts and, as it rots, releases toxic gases that affect the lives of local communities.