<i>Sargassum</i> Enrichment in Mesoscale Eddies of the Great Atlantic <i>Sargassum</i> Belt

Pelagic <i>Sargassum</i> has increased dramatically in the past decade, primarily in the annually recurrent Great Atlantic <i>Sargassum</i> Belt (GASB) that extends from the coast of West Africa to the Gulf of Mexico. Using satellite observations of <i>Sargassum</i> density and mesoscale eddies from 2011 to 2023, we investigate whether more <i>Sargassum</i> can be found in mesoscale eddies. Cyclonic eddies were found to contain 6%-47% more <i>Sargassum</i> (relative to eddy-free waters) across all selected regions within the GASB, with the highest <i>Sargassum</i> density in their inner cores (<0.5 eddy radius). Impacts of anticyclonic eddies were weaker and varied between regions. In addition, <i>Sargassum</i> enrichment tended to be higher in eddies with greater size or amplitude, such as the North Brazil Current rings and those in the Caribbean Sea. These findings may inform <i>Sargassum</i> mitigation strategies, for example, through physical removal in targeted locations.