The fourth webinar in this series will take place on Monday, 30 November 2020 with focus on Caribbean, where by 2018, the mats had grown into the largest macroalgae bloom in recorded history, an 8,850 km long mass extending from the central Atlantic and Caribbean Sea to West Africa and the Gulf of Mexico. Chunks of Sargassum, circulated by ocean currents, now regularly wash ashore in the Caribbean, where they rot on the beaches, giving off a strong, sulfurous stench.