Increased temperature mitigates the effects of ocean acidification on the calcification of juvenile Pocillopora damicornis, but at a cost

This study tested the interactive effects of increased seawater temperature and CO2 partial pressure (pCO(2)) on the photochemistry, bleaching, and early growth of the reef coral Pocillopora damicornis. New recruits were maintained at ambient or high temperature (29 or 30.8 A degrees C) and pCO(2) (similar to 500 and similar to 1100 mu atm) in a full-factorial experiment for 3 weeks. Neither a sharp decline in photochemical efficiency (Fv/Fm) nor evident bleaching was observed at high temperature and/or high pCO(2). Furthermore, elevated temperature greatly promoted lateral growth and calcification, while polyp budding exhibited temperature-dependent responses to pCO(2). High pCO(2) depressed calcification by 28% at ambient temperature, but did not impact calcification at 30.8 A degrees C. Interestingly, elevated temperature in concert with high pCO(2) significantly retarded the budding process. These results suggest that increased temperature can mitigate the adverse effects of acidification on the calcification of juvenile P. damicornis, but at a substantial cost to asexual budding.