The Sargasso Sea is a freefloating(pelagic) kelpdominated ecosystem in the western North Atlantic. It is bounded by the Gulf Stream, the Canaries Current, and other currents which together produce an ever circulating boundary. The local pattern of distribution appears to also be affected by both wind and thermal fronts, and more broadly may be affected by the action of storms. Attempts to quantify the amount and distribution of Sargassum in the Atlantic have met with many difficulties, including changes with seasonality and regional patchiness.
Two species constitute the majority of the algae here, primarily Sargassum natans, and most of the rest is Sargassum fluitans. These two species apparently evolved from other anchored species of Sargassum, providing the basis of this bizarre ecosystem. Sargassum stays afloat by producing gasfilled bladders which act like buoys. You can see these in the picture at left; the picture also shows the typical jaggededged blades. Life here is precarious for animals who are poor swimmers they
must maintain a firm grip on floating mats of kelp, or be lost to the ocean depths.
Such a floating ecosystem of course will have difficulties in acquiring nutrients, and will therefore be
severely limited by access to such nutrients. Many of the organisms which live here survive by being
generalists, not limiting themselves to a single food source but making use of whatever is available. The most common crab is a generalist carnivore, eating many different kinds of prey. It is also interesting that this ecosystem has no animals which are strict herbivores, but rather they are omnivores, switching between diets of eating algae and animals. This may in part be due to the rubbery, chemicalladen nature of Sargassum.
The accumulated mats of Sargassum support a wide variety of animal life, some of which depend on the kelp for only a part of their life. Other organisms spend their whole life among the algae, and this diversity of life has been called a "floating jungle". Some of the more unusual forms include fish and crabs which are camouflagued to look like Sargassum. Perhaps the best known of these is the pipefish Syngnathus pelagicus, a relative of the seahorse. This fish is brownishgreen, and is covered by flaps of skin which resemble the kelp blades. There are more than 50 fish species whose lives are linked to Sargassum, and a myriad of invertebrates, including gastropods, polychaetes, bryozoans, anemones, and seaspiders.
The most numerous inhabitants are hydroids and copepods.
Two species constitute the majority of the algae here, primarily Sargassum natans, and most of the rest is Sargassum fluitans. These two species apparently evolved from other anchored species of Sargassum, providing the basis of this bizarre ecosystem. Sargassum stays afloat by producing gasfilled bladders which act like buoys. You can see these in the picture at left; the picture also shows the typical jaggededged blades. Life here is precarious for animals who are poor swimmers they
must maintain a firm grip on floating mats of kelp, or be lost to the ocean depths.
Such a floating ecosystem of course will have difficulties in acquiring nutrients, and will therefore be
severely limited by access to such nutrients. Many of the organisms which live here survive by being
generalists, not limiting themselves to a single food source but making use of whatever is available. The most common crab is a generalist carnivore, eating many different kinds of prey. It is also interesting that this ecosystem has no animals which are strict herbivores, but rather they are omnivores, switching between diets of eating algae and animals. This may in part be due to the rubbery, chemicalladen nature of Sargassum.
The accumulated mats of Sargassum support a wide variety of animal life, some of which depend on the kelp for only a part of their life. Other organisms spend their whole life among the algae, and this diversity of life has been called a "floating jungle". Some of the more unusual forms include fish and crabs which are camouflagued to look like Sargassum. Perhaps the best known of these is the pipefish Syngnathus pelagicus, a relative of the seahorse. This fish is brownishgreen, and is covered by flaps of skin which resemble the kelp blades. There are more than 50 fish species whose lives are linked to Sargassum, and a myriad of invertebrates, including gastropods, polychaetes, bryozoans, anemones, and seaspiders.
The most numerous inhabitants are hydroids and copepods.
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