Adult low pH exposure influences larval abundance in Pacific oysters (Crassostrea gigas)

Abstract

As negative effects of ocean acidification are experienced by coastal ecosystems, there is a growing trend to investigate the effect ocean acidification has on multiple generations. Parental exposure to ocean acidification has been shown to induce larval carryover effects, but whether or not an acute exposure to a stressor as an adult can influence the larval generation long after the stress has been removed has yet to be tested. To assess how a temporary exposure to experimental ocean acidification affects the ecologically and commercially relevant Pacific oyster (Crassostrea gigas), adult oysters were exposed to either low pH (7.31 ± 0.02) or ambient pH (7.82 ± 0.02) conditions for seven weeks. Oysters were then held for eight weeks in ambient conditions, and subsequently reproductively conditioned for four weeks at ambient pH. After conditioning, oysters were strip-spawned to create four families based on maternal and paternal ocean acidification exposure. The number of D-hinge larvae were counted eighteen hours post fertilization. A sex-specific broodstock response was observed, where female exposure to low pH conditions resulted in fewer D-hinge larvae. This study demonstrates that the effects of ocean acidification can last beyond the time from when the environmental perturbation is experienced. Broadening the understanding of environmental memory will be valuable when considering an organism’s ability to persist in the face of environmental change.