A raft of brown-colored seaweed in the Atlantic Ocean is so vast it can be seen from space. "Following the big 2018 blooms, doctors in Martinique and Guadeloupe reported thousands of people going to clinics with breathing complications from the air that was coming off these rotting piles of sargassum," he said. Typically, floating rafts of sargassum accumulate in a part of the North Atlantic called the Sargasso Sea