Ocean acidification can be expected to drive substantial changes in ocean ecosystems during this century, according to a study that assesses the sensitivities of diverse marine animal groups to carbon dioxide concentrations. These findings, published online this week in Nature Climate Change, provide cause for concern about ocean ecosystems and the people dependent upon them.

Ocean acidification is known to affect some marine organisms, but the severity of the threat to ecosystems remains poorly understood. To address this issue, Astrid Wittmann and Hans-O. Portner evaluate the sensitivities of five animal taxa - corals, echinoderms, molluscs, crustaceans and fishes - to a wide range of carbon dioxide concentrations.

The authors found that all of the groups studied were negatively impacted by moderate ocean acidification, albeit in different ways and to different extents. Among the invertebrates, corals, echinoderms and molluscs suffer the most, whereas crustaceans were relatively resistant. Responses of fishes were less clear.The authors conclude that the diversity of responses could lead to profoundly altered ecosystems in the future.