Seawater carbonate chemistry and calcification data for widespread scope for coral adaptation under combined ocean warming and acidification

Here, we take advantage of the ability to sample genetically distinct coral colonies (genets) to produce genetically identical clonal fragments (ramets) and use an identical twin design to estimate the broad sense heritability (H2) and potential for adaptation of coral calcification rates under warming, acidification and the combination of both factors. Corals of eight species were exposed to one of four treatments: (i) control (present-day temperature and pH), (ii) ocean warming (+2°C and present-day pH), (iii) ocean acidification (present-day temperature and −0.2 pH units), or (iv) combined future ocean (+2°C and −0.2 pH units). This study was conducted over 1 year, providing the corals with time to acclimatize to the treatments and helping to ensure that the measured calcification responses were a result of heritable variation among them rather than differences in their short-term histories.