Sargasssum brings another ‘golden tide’ on our shorelines
Rahanna Juman,
Institute of Marine Affairs
For yet another year, massive quantities of sargassum are seen washing up along our coasts and is causing concern among fisherfolk and other beach users. This new source of sargassum is now linked to climate change and ocean eutrophication, and these are likely to continue supporting significant sargassum blooms into the future. As such, annual mass influxes of sargassum into the Caribbean Sea are now being considered as the new normal, requiring sustainable management responses and long-term adaptation (Desrochers et al. 2020).
Pelagic (free-floating) sargassum, a brown algae from the equatorial Atlantic, comprises a mixture of two or possibly three different sargassum species, namely sargassum fluitans III, sargassum natans I, and sargassum natans VIII (Schell, Goodwin, and Siuda 2015) that forms large floating mats often referred to as “golden tides.” These species are unique in that they are the only sargassum species to spend their entire lifecycle afloat, instead of attached to the seafloor. As such, they are considered to be holopelagic, and to only occur in the Atlantic Ocean (Desrochers et al. 2020). The Atlantic holopelagic sargassum is also thought to only reproduce vegetatively through growth and fragmentation, and is able to double its biomass very quickly under the right conditions (nine to 20 days; Hanisak and Samuel 1987, Lapointe 1986).