Scleractinian coral species survive and recover from decalcification.

Anthropogenic-driven accumulation of carbon dioxide in the atmosphere and projected ocean acidification have raised concerns regarding the eventual impact on coral reefs. This study demonstrates that skeleton-producing corals grown in acidified experimental conditions are able to sustain basic life functions, including reproductive ability, in a sea anemone-like form and will resume skeleton building when reintroduced to normal modern marine conditions. These results support the existence of physiological refugia, allowing corals to alternate between nonfossilizing soft-body ecophenotypes and fossilizing skeletal forms in response to changes in ocean chemistry. This refugia, however, does not undermine the threats to reef ecosystems in a high carbon dioxide world.