The Great Atlantic Sargassum Belt, an 8,000-kilometre-wide brown mass of blanketed seaweed, reached a record-high volume for the month of March.

The Great Atlantic Sargassum Belt is not new, but it is on the move and could potentially wreak havoc on beaches in Florida, Mexico and the Caribbean this summer.

The picture-perfect beaches and turquoise water of the Caribbean are increasingly being fouled by mats of decaying seaweed that attract biting sand fleas and smell like rotten eggs.