Scientists come closer to solving Caribbean seaweed mystery

Mexican Marines stand next to sargassum removed from the sea as part of a government program to remove the algae, in Cancun, Mexico July 20, 2021. Picture taken July 20, 2021. REUTERS/Paola Chiomante

(Reuters) - Scientists were baffled when a band of seaweed longer than the entire Brazilian coastline sprouted in 2011 in the tropical Atlantic - an area typically lacking nutrients that would feed such growth.

A group of U.S. researchers has fingered a prime suspect: human sewage and agricultural runoff carried by rivers to the ocean.