Image caption
How seaweed from the Sargasso Sea could have spread to the tropical Atlantic and Caribbean. Due to stronger-than-usual westerly winds in 2009-2010, the normal surface currents in the subtropical gyre (solid lines) reached farther east than usual (dotted lines). Sargassum could have reached the waters near Gibraltar by spring 2010, and the tropical Atlantic by spring of 2011. By summer, piles of Sargassum were reaching beaches in the Caribbean. Animation by NOAA Climate.gov. Adapted from original in Johns et al., 2020.