Elevated pCO2 causes developmental delay in early larval Pacific oysters, Crassostrea gigas

Increasing atmospheric CO2 equilibrates with surface seawater, elevating the concentration of aqueous hydrogen ions. This process, ocean acidification, is a future and contemporary concern for aquatic organisms, causing failures in Pacific oyster (Crassostrea gigas) aquaculture. This experiment determines the effect of elevated pCO(2) on the early development of C. gigas larvae from a wild Pacific Northwest population. Adults were collected from Friday Harbor, Washington, USA (48A degrees 31.7'N, 12A degrees 1.1'W) and spawned in July 2011. Larvae were exposed to Ambient (400 mu atm CO2), MidCO(2) (700 mu atm), or HighCO(2) (1,000 mu atm). After 24 h, a greater proportion of larvae in the HighCO(2) treatment were calcified as compared to Ambient. This unexpected observation is attributed to increased metabolic rate coupled with sufficient energy resources. Oyster larvae raised at HighCO(2) showed evidence of a developmental delay by 3 days post-fertilization, which resulted in smaller larvae that were less calcified.