By spewing carbon dioxide from smokestacks and tailpipes at a gigatons-per-year pace, humans are lowering the pH of the world ocean. The geochemical disruption will reverberate for tens of thousands of years. It’s less clear how marine life will fare. With nothing in the geologic record as severe as the ongoing plunge in ocean pH, paleontologists can’t say for sure how organisms that build carbonate shells or skeletons will react. In the laboratory, corals always do poorly. The lab responses of other organisms are mixed. In the field, researchers see signs that coral growth does slow, oyster larvae suffer, and plankton with calcareous skeletons lose mass.
Kerr, R. A., 2010. Ocean acidification unprecedented, unsettling. Science 328(5985):1500-1501. Article (subscription required).