A Caribbean Influx of Deadly Weed

Massive rafts of Sargassum seaweed that originate in the Sargasso Sea, an area contained normally by the central gyre of the Atlantic currents, have been coming ashore in recent years, not only in the Eastern Caribbean, but also along the coasts of Mexico, Trinidad, Tobago and some West African nations. It's been especially bad in Barbados, an island normally noted for its pristine white beaches, where some are now buried beneath vast expanses of rotting seaweed, with some mounds as much as six feet high (1.8m).

Besides clogging boats' cooling water intakes, its effects can be deadly to wildlife. In Barbados, it has killed three dolphins and seven endangered green turtles. In 2015, the worst year, more than 40 green and hawksbill turtles died.

Under normal circumstances, floating mats of Sargassum form a thriving ecosystem, but for air-breathing animals, it can be a problem because it traps them when they try to break through to the surface.

Be aware: If a mat of Sargassum floats overhead while you are diving, you will not have clear access to the surface.