Scientists finally discover what’s fueling massive sargassum blooms

Massive Sargassum blooms sweeping across the Caribbean and Atlantic are fueled by a powerful nutrient partnership: phosphorus pulled to the surface by equatorial upwelling and nitrogen supplied by cyanobacteria living directly on the drifting algae. Coral cores reveal that this nutrient engine has intensified over the past decade, perfectly matching surges in Sargassum growth since 2011. By ruling out older theories involving Saharan dust and river runoff, researchers uncovered a climate-driven process that shapes when and where these colossal seaweed mats form.