The Sargasso Sea is often covered in rafts of sargassum, an unusual bulbous seaweed that forms a floating surface in which tuna, dolphinfish and crabs raise their young.
The fishing vessels that criss-cross this 4mn sq km of water, the world’s only sea defined by ocean currents rather than a coastline, bear the flags of Spain, Taiwan, the US and China and are a constant threat to its marine life. On the sea floor off its eastern flank, Russia and other countries are exploring how they might extract copper, silver and gold from the rich polymetallic sulphides that spew from volcanic vents.
Negotiators of the new UN Biodiversity Beyond National Jurisdiction treaty say it could start to curb this rush for the marine resources — provided that major powers, which tend to value oceans for their fishing grounds, oil reserves and shipping lanes rather than their biodiversity, can be persuaded to support it.