09/23/2010 - The Sargasso Sea has no shores. The 2 million-sq.-mi. body of water in the middle of the Atlantic is defined by two features: the ocean currents forming the North Atlantic subtropical gyre, which cycles around the sea, and sargassum, the free-floating golden-brown seaweed. The sargassum can be found scattered throughout the sea, sometimes entwined in vast waterborne mats. When Christopher Columbus encountered the sargassum while crossing the Atlantic, he ordered his men to fathom the depths, believing he had struck land. The oceanographer Sylvia Earle, though she prefers not to think in land-based metaphors, calls the sargassum "the golden rain forest of the sea," a base for scores of juvenile creatures, a floating nursery in a sea that was long believed to be a watery desert. She has traveled to Bermuda, on the western fringes of the Sargasso Sea, to see the sargassum and the ocean life she has worked for decades to protect. "The sargassum is the shelter," she says as her boat passes beyond Bermuda's coral reefs. "It is the island in the stream."
Even worse are long-term changes to the very chemistry of the seas. The oceans have gradually warmed, depriving species of nutrients and triggering deadly coral-bleaching events. Unusually high temperatures this year could wipe out coral around the planet, accelerating the destruction of the most valuable habitats in the oceans. Thanks to all the fossil fuels humans have burned, the seas have also become more acidic because dissolving CO2 in water lowers the pH — the oceans store 50 times as much carbon as the atmosphere does — and that change will have consequences no one can predict, though none are likely to be positive. The seas seem as invulnerable as they are immense. But if we thought the oceans were too vast for human beings to affect or we were counting on the waters to purify themselves, we were wrong. "The loss we could suffer goes beyond aesthetics," says Josh Reichert, managing director of the Pew Environment Group. "It's a loss to ourselves."
Read the full article Code Blue on the Time Web site.