Meeting Abstract

101.10  Wednesday, Jan. 7  Ocean acidification alters skeletogenisis in larvae of the sea urchin Lytechinus pictus: evidence from morphometric and microarray data O’DONNELL, M.J.*; TODGHAM, A.E.; SEWELL, M.A.; HAMMOND, L.M.; RUGGIERO, K.; FANGUE, N.A.; ZIPPAY, M.L.; HOFMANN, G.E.; Univ. of Wash. Friday Harbor Labs; Univ. of California, Santa Barbara; Univ. of Aukland; Univ. of California, Santa Barbara; Univ. of Aukland; Univ. of California, Santa Barbara; Univ. of California, Santa Barbara; Univ. of California, Santa Barbara mooseo@moosecraft.org

Ocean acidification, the reduction of ocean pH via the absorption of anthropogenic atmospheric CO₂, is expected to impact marine ecosystems through effects on marine calcifying organisms. These impacts are not well understood at the community and ecosystem levels. A current focus in ocean acidification research is to understand the resilience organisms possess to withstand such changes, and to extend these investigations beyond calcification, addressing impacts on other vulnerable physiological processes. Using morphometric methods and gene expression profiling with a DNA microarray, we explore the impacts of high CO₂ conditions on development of the sea urchin, Lytechinus pictus, a pelagic larvae that forms a calcium carbonate endoskeleton. Larvae were raised from fertilization to pluteus stage in seawater with elevated CO₂ conditions based upon IPCC emissions scenarios. Morphometric analysis showed significant effects of enhanced CO₂ on both size and shape of larvae; those grown in a high CO₂ environment were smaller, and with a more triangular body than those raised in normal CO₂ conditions. Gene expression profiling showed that numerous genes central to energy metabolism and biomineralization were down-regulated in the larvae in response to elevated CO₂, whereas only a few genes in ion regulation and acid-base balance pathways were induced. These results suggest that, although larvae are able to form an endoskeleton, development at elevated CO₂ levels has consequences for physiological function as shown by changes in the larval transcriptome.