Record sargassum seaweed blankets Caribbean coasts

A record-breaking bloom of sargassum seaweed is blanketing coastlines across the Caribbean, Gulf of Mexico, and tropical Atlantic, with about 27 million metric tons recorded in July 2026. The Great Atlantic Sargassum Belt, which has grown since 2011, is now self-sustaining, with blooms reproducing locally. Scientists from the University of South Florida and Georgia Tech warn the phenomenon is likely to persist. The seaweed smothers shorelines, harms marine life, releases toxic gases, and disrupts tourism and fishing. Mexico is investing $115 million to combat the seaweed, deploying Navy personnel and boats, while United States — Puerto Rico has declared a state of emergency. Governments and entrepreneurs are exploring uses for sargassum as biofuel, fertilizer, and construction material, with projects in Mexico, Barbados, and Brazil. A joint EU-Caribbean conference on sargassum is planned for October in Cancun.