Sargassum spp. Community Studies
The Sargasso Sea is a loosely defined geographic area bound by currents circulating as the North Atlantic Gyre, the Gulf Stream being the most noteworthy current occupying the western boundary. The Sargasso Sea is centered in a subtropical convergent zone where surface water slowly sinks, leaving the area nearly devoid of nutrients and thus nearly devoid of life—a biological desert of sorts. However, where the Sargasso Sea is poor in numbers it is rich in diversity, as well as a history that borders on the mythological. This area of the North Atlantic is home to two species of itinerant, floating seaweed, Sargassum fluitans and Sargassum natans. These plants were first described by Christopher Columbus as vast mats upon the ocean, so large he feared that his ships were about to run aground. A diverse assemblage of species lives on and among these “small islands” of seaweed, many of which are endemic to this relatively ephemeral environment. It is a unique environment and serves as a manageable microcosm in which SEA students have examined fundamental ecological concepts, including island biogeography, community succession, and trophic cascades.