Meeting Abstract

47.2  Saturday, Jan. 5  Ocean acidification in the Northeast Pacific: a genomics perspective EVANS, T.G.*; HOFMANN, G.E.; California State University East Bay; University of California Santa Barbara

Ocean acidification (OA), the decline in seawater pH caused by the absorption of atmospheric CO2, has emerged as a global-scale consequence of anthropogenic activity. However, coastal zones of the Northeast Pacific Ocean already experience declines in pH as a result of oceanic upwelling, which exposes contemporary marine populations to seawater conditions not expected to occur in other parts of the ocean until 2100. To explore the impacts of OA in the Northeast Pacific, we capitalized on the availability of genomic resources for a keystone calcifier in the region, the purple sea urchin (Strongylocentrotus purpuratus) and monitored gene expression in larvae raised in laboratory mesocosms that simulate future ocean scenarios. We addressed three important questions surrounding the biological effects of OA in the Northeast Pacific: 1.) What are the molecular mechanisms that allow species to sustain function in a low pH ocean? 2.) Do responses to OA differ across species ranges? 3.) How will future ocean warming combine with OA to influence organismal function? Genome-wide transcriptomics provided considerable insight into all three questions. Firstly, modifying the transport and bioavailability of calcium, the primary cation used in the biomineralized structures of S. purpuratus, appears central to maintaining calcification in a low pH ocean. Secondly, S. purpuratus responded differently to OA across its biogeographic range and some populations may already be living near acclimatization thresholds. Finally, simultaneous exposure to warm and acidic seawater may negatively impact the cell cycle with potential ramifications for growth and development in future oceans.