Are heat-tolerant corals primed to survive ocean acidification?

April 16, 2014 @ 01:20 pm to 02:10 pm

Andrea Chan, Penn State

104 Forest Resources Building

Increased global temperatures and decreased oceanic pH are expected to significantly reduce coral species diversity and abundance by 2050. Little is known about how coral communities respond to the combined effects of these parameters. I propose to test the effects of increased ocean acidification and warming on calcification in coral species that are already heat tolerant in Eastern Indonesia. Previous work has demonstrated that increased temperatures elevate calcium carbonate precipitation enough to potentially compensate for reduced calcification caused by ocean acidification, allowing corals to continue to grow under these conditions. Yet this outcome is reliant on two factors: whether corals can up-regulate pH at their sites of calcification, and whether the temperature elevation remains within the corals thermal range. Reefs in Eastern Indonesia, where water temperatures exceed 35 C daily without coral bleaching or mortality, will provide a natural laboratory to test corals responses to the combined effects of temperature and lower pH. Four coral fragments from five Acropora loripes and five Porites rus colonies each will be collected from three high temperature pools in Eastern Indonesia. Following acclimation, fragments from each individual will be placed in tanks with four treatments (high temperature&low pH, high temperature&normal pH, normal temperature&low pH, and normal temperature&normal pH). I hypothesize that the heat-tolerant corals will maintain higher calcification rates, and thus continue to grow, under the combined effects of increased temperature and lower pH. This work will increase current understanding of the interaction effects between temperature and pH on coral calcification, thus evaluating coral potential to withstand projected climate change with practical applications for ecosystem management.