Beaching and Natural Removal Dynamics of Pelagic Sargassum in a Fringing‐Reef Lagoon

Massive quantities of the pelagic brown macroalgae Sargassum spp. (sargassum) have been invading Caribbean and West African shores since 2011, causing devastating effects on coastal ecosystem local economy. Little is known about sargassum beaching dynamics capacity system to naturally remove beached sargassum. Here, we characterize temporal variation in arriving a reef lagoon using 5.2-year data set hourly optical imagery, identify governing hydrometeorological conditions. Image classification reveals interannual variability start, duration, intensity arrival season. Arrivals are associated with relatively low energy onshore directed winds waves, offshore abundance Furthermore, nearshore mat size found decrease decreasing wave/wind energy. Once beaches, berm wrack formed. Natural removal was observed under elevated water levels increased wave action. Three types were distinguished, depending level respect crest height toe : gradual destruction gaps developing seaward edge that grow larger time (Type I; ) abrupt part depositing upper beach II; or dunes III; ). Higher waves activate circulation, which suspected flush out lagoon. We propose conceptual model system.