Paper detail

Carriers of \emph{Sargassum} and mechanism for coastal inundation in the Caribbean Sea

We identify effective carriers of \emph{Sargassum} in the Caribbean Sea and describe a mechanism for coastal choking. Revealed from satellite altimetry, the carriers of \emph{Sargassum} are mesoscale eddies (vortices of 50-km radius or larger) with coherent material (i.e., fluid) boundaries. These are observer-independent -- \emph{unlike} eddy boundaries identified with instantaneously closed streamlines of the altimetric sea-surface height field -- and furthermore harbor finite-time attractors for networks of elastically connected finite-size buoyant or "inertial" particles dragged by ocean currents and winds, a mathematical abstraction of \emph{Sargassum} rafts. The mechanism of coastal inundation, identified using a minimal model of surface-intensified Caribbean Sea eddies, is thermal instability in the presence of bottom topography.