When Columbus reached the deep blue waters of the central North Atlantic, he thought he was very close to shore. After all, there was suddenly an abundance of plant life in the form of a floating algae, which he called, simply, "weed." His sailors, meanwhile, feared that their ships would become irretrievably entangled in the stuff.
Their fears were misplaced as were Columbus' hopes. The weed which scientists ultimately dubbed sargassum, after a Portuguese word for it is neither sturdy nor abundant enough to ensnare a ship of any size. And even the westernmost boundaries of the Sargasso Sea a two-million-square-mile ellipse of deep-blue water adrift in the North Atlantic lie many hundreds of miles from the North American shore.
Defined by a floating lens of warm, exceptionally clear water, the Sargasso Sea drifts, its location determined by the changing ocean currents that, flowing in a clockwise promenade, form its perimeter. The algae that riddles its surface is actually a deceptively lush veneer to a stretch of ocean that is relatively devoid of life at deeper levels. But even in this ocean "desert," as marine biologist Henry Genthe shows us in this tour of the sea, there is an intricate web of life that has adapted to existence among the "weed."