Parental exposure of Eastern oysters (Crassostrea virginica) to elevated pCO2 mitigates its negative effects on early larval shell growth and morphology

Abstract

AbstractLarvae of marine calcifying organisms are particularly vulnerable to the adverse effects of elevated pCO2 on shell formation because of their rapid calcification rates, reduced capacity to isolate calcifying fluid from seawater, and use of more soluble polymorphs of calcium carbonate. However, parental exposure to elevated pCO2 could benefit larval shell formation through transgenerational plastic responses. We examined the capacity of intergenerational exposure to mitigate the adverse effects of elevated pCO2 on Eastern oyster (Crassostrea virginica) early larval shell growth, shell morphology, and survival. Adult oysters were exposed to control (572 ppm pCO2) or elevated pCO2 (2827 ppm pCO2) conditions for 30 d during reproductive conditioning. Offspring from each parental treatment were produced using a partial North Carolina II cross design and grown under control and elevated pCO2 conditions for 3 d. We found evidence of transgenerational plasticity in early larval shell growth and morphology, but not in survival, in response to the parental pCO2 exposure. Larvae from parents exposed to elevated pCO2 exhibited faster shell growth rates than larvae from control parents, with this effect being significantly larger when larvae were grown under elevated pCO2 compared to control conditions. Parental exposure to elevated pCO2, however, was insufficient to completely counteract the adverse effects of the prescribed elevated pCO2 on early larval shell formation and survival. Nevertheless, these results suggest that oysters have some capacity to acclimate intergenerationally to ocean acidification.