Sargassum is a brown seaweed that’s been wreaking havoc in the Caribbean over the last decade, and in particular, along Mexico’s Cancun and Mayan Riviera beaches. It started appearing a decade ago and has exploded in recent years, due to a combination of fertilizer runoff, warmer temperatures, and deforestation. More than 60,000 tons of the algae washed up on Mexico’s Caribbean beaches in mid-May — a new record for the region. It’s befouling Cancun’s famed beaches and harming marine life. Reporter Michael Fox has the story of Omar Vasquez Sanchez, an entrepreneur turning seaweed into something useful.