Ocean acidification and warming reduce juvenile survival of the fluted giant clam, Tridacna squamosa

Anthropogenic carbon dioxide (CO2) emissions are causing ocean acidification and ocean warming; however, the synergistic effects of these stressors on giant clams are completely unknown. Juveniles of the fluted giant clam, Tridacna squamosa Lamarck, 1819, were exposed to present-day control seawater (416 mu atm pCO(2)) and seawater treated with CO2 to simulate ocean conditions predicted for the next 50-100 years (622 mu atm pCO(2) and 1019 mu atm pCO(2)). These CO2 treatments were cross-factored with seawater temperatures of similar to 28.5 degrees C, similar to 30.0 degrees C and similar to 31.5 degrees C. The majority of mortality occurred between 40 and 60 days. Survival of juveniles decreased with increasing pCO(2) and decreased with increasing seawater temperature. The combination of the highest pCO(2) and both the moderate and highest seawater temperatures resulted in the lowest survival of <20 % indicating survival of T. squamosa could be reduced considerably at ocean conditions predicted to occur around the end of this century.