‘On the one hand, the results of this study are optimistic,’ Cohen says. ‘Even though many experiments and other studies of naturally low pH reefs show that ocean acidification negatively impacts calcium carbonate production, as well as coral diversity and cover, we are not seeing that on Palau. And that gives us hope that some coral reefs — even if it is a very small percentage — might be able to withstand future levels of ocean acidification. But there’s also a cautionary side, even for those coral communities able to maintain their diversity and growth as the oceans become more acidic, increased rates of bioerosion and dissolution seem inescapable.’