Meeting Abstract

72.2  Monday, Jan. 6 08:15  Genetically determined shifts in metabolic energy allocation in response to ocean acidification APPLEBAUM, S.L.*; PAN, F.; HEDGECOCK, D.; MANAHAN, D.T.; University of Southern California; University of Southern California; University of Southern California; University of Southern California sappleba@usc.edu

Current evidence suggests that future scenarios of ocean acidification (OA) will impact the metabolism of marine organisms. Genetically determined variation in allocation of energy to essential physiological processes could differentially impact the adaptive potential of individuals under environmental stress. Predicting the impact of OA and other environmental changes on natural populations will require an understanding of the mechanisms of variation in biological responses and the adaptive potential of different genotypes. We used controlled crosses of inbred lines of the Pacific oyster Crassostrea gigas to produce F1 hybrid families. Such families are equivalent to non-inbred wild types but are genetically defined and permit natural biological variation to be experimentally partitioned. Hybrid larvae were analyzed for phenotypic variation in growth and allocation of ATP to major energy-consuming processes – protein synthesis and ion homeostasis (Na⁺, K⁺-ATPase). Combined, these two processes accounted for up to 75% of ATP utilization in larvae. Under present-day conditions (380 ppm CO₂) contrasting phenotypic patterns of metabolic allocation were evident between hybrid families growing at significantly different rates. Larvae of a single family exposed to either present-day or near-future OA conditions (800 ppm CO₂) substantially changed phenotypic metabolic allocation in the OA-treated larvae. Further, the response of metabolic reallocation in OA varied between families. These genotype-by-environment interactions suggest that some individuals have greater physiological resilience to environmental stress. Understanding the mechanistic basis of genetically determined resilience will greatly improve abilities to predict potential to adapt to environmental change.