Some 27 million metric tons of self-sustaining sargassum have been recorded in the Atlantic, Caribbean and Gulf of Mexico in July, according to a report released Friday by the University of South Florida’s Optical Oceanography Lab.

Seaweed composing the Great Atlantic Sargassum Belt hit near-record levels in June 2026, with the Caribbean Sea and Gulf of America both reaching all-time highs.

These vast mats of smelly seaweed may have entered a self-sustaining cycle, effectively feeding their own expansion