46.5 Saturday, Jan. 5 Natural variation, and the capacity to adapt to ocean acidification in the sea urchin Strongylocentrotus purpuratus KELLY, M.W.*; PADILLA-GAMINO, J.L.; HOFMANN, G.E.; Unversity of California, Santa Barbara; Unversity of California, Santa Barbara; Unversity of California, Santa Barbara firstname.lastname@example.org
There is a rapidly growing body of literature documenting potential negative effects of CO2-driven ocean acidification (OA) on marine organisms. However, nearly all of this work has focused on the effects of future conditions on modern populations, ignoring the role of adaptation. We measured the capacity to adapt to OA in two populations of the ecologically important purple sea urchin Strongylocentrotus purpuratus by using a breeding experiment to estimate additive genetic variance for larval size under future high pCO2/low pH conditions. Although larvae reared under future conditions were smaller than those reared under present-day conditions, there was also abundant genetic variation for body size under elevated pCO2, indicating that this trait can evolve. Accounting for the observed genetic variation in models of future larval size and demographic rates substantially altered projections of performance for this species in the future ocean. There were also subtle differences in larval size between populations of this species under high pCO2 rearing conditions in the laboratory, consistent with local adaptation to carbonate chemistry in the field. These results suggest that spatially varying selection may help to maintain genetic variation necessary for adaptation to future ocean conditions.