Native Olympia oysters, which once thrived along the Pacific Northwest coast until over-harvesting and habitat loss all but wiped them out, have a built-in resistance to ocean acidification during a key shell-building phase after spawning, according to a newly published study. Unlike the commercially raised Pacific oysters, Olympia oysters don’t begin making their shells until 2-3 days after fertilization and make them far more slowly, which helps protect them from corrosive water during this critical development phase, said Oregon State University’s George Waldbusser, principal investigator on the project. Pacific oysters, on the other hand, only have a six-hour window to develop their calcium carbonate shell, and when exposed to acidified water, their energy stores become depleted. The larval oysters may get through the shell-building stage, Waldbusser said, but they often will not have enough energy to survive. Results of the study have been published in the Journal of Limnology and Oceanography.