Meeting Abstract

S9-1.7  Monday, Jan. 7  Physiological response and local adaptation of marine invertebrates to natural variation in the ocean acidification seascape HOFMANN, Gretchen/E; UC Santa Barbara hofmann@lifesci.ucsb.edu

Understanding how marine ecosystems will respond to future anthropogenic change – e.g., ocean warming and ocean acidification – is a critical priority for the research community. Central to this goal is knowing whether marine organisms possess the physiological plasticity or adaptation capacity to adjust in a rapidly changing environment and thus avoid extinction. In this presentation I will overview results from our research program that examines physiological plasticity and local adaptation in populations of marine invertebrates along the U.S. Pacific coast. Here, variation in upwelling regimes from Washington to southern California generate spatial and temporal gradients in concentration of CO₂ that shoal to surface waters during upwelling events, bringing cold, low pH waters to benthic populations near shore. These episodic events of natural acidification likely act as a selection regime where some populations may have more resilience to future ocean acidification due to local adaptation. In order to identify the mechanistic underpinnings of calcifying marine invertebrates to acclimatize or adapt to increasing CO₂, we co-located oceanographic sensors for pCO₂ and pH with biological measurements to examine physiological plasticity (e.g., metabolic rates, change in body size and transcriptomic responses). Additionally, genetic surveys have been done to identify genetic variation. The results of the project suggest that there is heterogeneity in seawater conditions across this large biogeographic space – the California Current Large Marine Ecosystem (CCLME) – and that the performance of two invertebrates, sea urchins and mussels, varies with this variation in a manner that suggests local adaptation and differential responses amongst species.