Sizing Up the Sargassum Belt

Core point

The Great Atlantic Sargassum Belt reached near-record levels in June 2026, with significant concentrations of seaweed observed in the Caribbean Sea and Gulf of America. This trend of increasing Sargassum has been ongoing since 2011, with the belt's abundance making it the second-highest recorded year. The proliferation of Sargassum can have both positive and negative impacts on marine ecosystems, providing habitat while also posing risks to coastal areas. Satellite observations are crucial for tracking the extent of Sargassum and preparing communities for its effects.