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The world’s oceans are deteriorating more rapidly than scientists had thought due to rising carbon dioxide levels and associated warming, according to a new analysis by European scientists. By many indicators, ocean conditions are even worse than outlined lastmonth by the U.N. Intergovernmental Panel on Climate Change’s assessment report on the physical effects of global warming, the researchers say. Sinking oxygen levels, which could decline by 1 to 7 percent by 2100, increasing ocean acidification, and overfishing of more than 70 percent of marine populations are among the biggest threats to ocean ecosystems, the scientists report in Marine Pollution Bulletin . Mollusks and other sensitive organisms are increasingly being found with corroded shells, a result of rising dissolved CO2 concentrations; within 20 to 40 years ocean acidity levels may reach the point where coral reefs are eroded faster than they can regenerate, the review said.