NECAN Sea Grant Webinar: Resilience to Ocean Acidification in Commercially Important Bivalves

Recording of the Northeast Coastal Acidification Network (NECAN) Webinar from November 13, 2019 Presented by Michelle Barbosa and Caroline Schwaner of Stony Brook University

As we near the end of the century, the fate of our marine environments becomes increasingly worrisome. With increasing carbon dioxide emissions, the pH of the ocean will decrease and thus have profound impacts on ocean chemistry. Ocean acidification (OA) has been predicted to have variable, but often adverse, impacts on the fitness of calcifying species. Bivalve species are considered to be among the most threatened taxa under the predicted end-of-the-century climate. In this presentation, we describe some of the physiological costs associated with resilience to OA and begin to uncover the molecular processes underlying resilience in bivalves. Our investigations into the effects of OA on bivalves have demonstrated differences in inter-species susceptibility to acidification and multiple stressors. Our study found contrasting patterns in growth for hard clam (Mercenaria mercenaria) and eastern oyster (Crassostrea virginica) larvae. Most strikingly, larval hard clams and eastern oysters are particularly sensitive to major bacterial pathogens under the predicted future climate. This vulnerability could facilitate the loss of ecologically and economically important species. To understand potential mechanisms for persistence of these species, a greater insight into the mechanisms and molecular processes underlying resilience is needed. This knowledge could be critical to determining the extent to which bivalve stocks are at risk in future climate conditions. Investigations in the potential for genetic bases for resilience to OA has uncovered many genes potentially acting in concert to affect the survival of the individual. Combining both RNAseq and RADseq technologies, our studies have demonstrated both changes in gene expression and selection for key single nucleotide polymorphisms (SNPs) underlying resilience to OA. These molecular features may be important for orchestrating survival in acidified seawater. The identification of these features is vital for selecting traits necessary for the persistence of aquaculture stocks under OA.