Contrary to expectations, a microscopic plant that lives in oceans around the world may thrive in the changing ocean conditions of the coming decades, a team of scientists reported on Thursday. The main threat to many marine organisms is not global warming but ocean acidification, as carbon dioxide from the air dissolves into the water and turns into carbonic acid. Acid dissolves calcium carbonate in the skeletons of corals, for example; many scientists fear that acidification of the oceans will kill many, if not most, coral reefs by the end of the century.Similar concerns have been raised about coccolithophores, single-cell, carbonate-encased algae that are a major link in the ocean food chain. Earlier experiments with a species of coccolithophore, Emiliania huxleyi, had found that higher acidity hindered the algae's ability to build the disks of carbonate that form its shell. In Friday's issue of the journal Science, however, scientists led by M. Debora Iglesias-Rodr