As summer vacation rolls around and hotels, restaurants and other hospitality companies gear up for a busy tourist season, coastal businesses in the U.S. Southeast, Puerto Rico and the Caribbean may be welcoming an unexpected guest—the Great Atlantic Sargassum Seaweed Belt. Businesses are bracing for this ten-million-ton mass of brown seaweed, which is floating on the ocean surface and extending from the west coast of Africa to the Gulf of Mexico.