By Sid Perkins
Large blooms of plankton often appear in ocean eddies, temporary swirls that sometimes bring cool, nutrient-rich water to the surface. When those organisms die, the carbon they contain has to go somewhere, but new studies suggest that very little of it sinks to the ocean floor and gets locked away in sediments. The new data might quash hopes that fertilizing the ocean surface could pull enough carbon dioxide from the atmosphere to substantially affect climate.
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Scientists find a larger average concentration of organic matter in deep ocean waters than can be explained by biological productivity at the sunlit surface above. To balance the budget, some researchers have pointed to the immense biomass generated in large ocean eddies (SN: 6/14/03, p. 375: Available to subscribers at Oceans Aswirl), much of which has been presumed to eventually fall to the ocean floor.