Anthropogenic climate change is likely to impact fitness and persistence of marine species in complex ways that are difficult to predict. Though occurrence of hypoxia and pH are linked under scenarios of global climate change, little research has been published on ocean acidification effects on animal physiology that also includes the interactive effects of genetic variation, adaptive potential, and simultaneous exposure to hypoxia. This project will test for interactive effects of acidification and hypoxia during sensitive early life stages of an ecologically and economically important marine mollusc (red abalone, Haliotis rufescens), as well as identify and characterize genetic variation associated with variable sensitivities to these stressors. Specifically, researchers will examine the effects of chronic and acute exposures on development; the impact of local evolution to varied ocean OA/hypoxia conditions on abalone sensitivity; and identify genetic markers predictive of variable sensitivity to climate stress. The project may result in genomic tools that facilitate screening of individuals and populations for variation that may be adaptive to future environments, allowing genome-enabled conservation and management of red abalone.