Project: Effect of Ocean Acidification on Early Life History Stages of the Antarctic Sea Urchins Sterechinus neumayeri

The research examine the effects of ocean acidification on embryos and larvae of a contemporary calcifier in the coastal waters of Antarctica, the sea urchin Sterechinus neumayeri. The effect of future ocean acidification is projected to be particularly threatening to calcifying marine organisms in coldwater, high latitude seas, making tolerance data on these organisms a critical research need in Antarctic marine ecosystems. Due to a high magnesium (Mg) content of their calcitic hard parts, echinoderms are especially vulnerable to dissolution stress from ocean acidification because they currently inhabit seawater that is barely at the saturation level to support biogenic calcification. Thus, cold-water, high latitude species with a high Mg-content in their hard parts are considered to be the 'first responders' to chemical changes in the surface oceans. Studies in this proposal will use several metrics to examine the physiological plasticity of contemporary urchin embryos and larvae to CO2-acidified seawater, to mimic the scenarios defined by IPCC models and by analyses of future acidification predicted for the Southern Ocean. The research also will investigats the biological consequences of synergistic interactions of two converging climate change-related stressors - CO2- driven ocean acidification and ocean warming. Specifically the research will (1) assess the effect of CO2-acidified seawater on the development of early embryos and larvae, (2) using morphometrics, examine changes in the larval endoskeleton in response to development under the high-CO2 conditions of ocean acidification, (3) using a DNA microarray, profile changes in gene expression for genes involved in biomineralization and other important physiological processes, and (4) measure costs and physiological consequences of development under conditions of ocean acidification. The proposal will support the training of undergraduates, graduate students and a postdoctoral fellow. The PI also will collaborate with the UC Santa Barbara Gevirtz Graduate School of Education to link the biological effects of ocean acidification to the chemical changes expected for the Southern Ocean using the 'Science on a Sphere' technology. This display will be housed in an education and public outreach center, the Outreach Center for Teaching Ocean Science (OCTOS), a new state-of-the-art facility under construction at UC Santa Barbara.      

Relevant Publications:

Evans, T.G and G.E. Hofmann. "Defining the limits of physiological plasticity in marine organisms: how gene-expression profiling can aid in predicting the consequences of ocean change," Phil. Trans. of Royal Society B, v.367, 2012, p. 1733.

Fangue, N.A., M.J. O'Donnell, M.A. Sewell, P.G. Matson, A.C. MacPherson and G.E. Hofmann. "A laboratory-based experimental system for the study of ocean acidification effects on marine invertebrate larvae," Limnol. Oceanogr.: Methods, v.8, 2010, p. 441.

Hofmann, G.E., T.R. Martz + 10 co-authors. "High-Frequency Dynamics of Ocean pH: A Multi-Ecosystem Comparison," PLoS ONE, v.6, 2011.

Kapsenberg, L., & Hofmann, G. E. Signals of resilience to ocean change: high thermal tolerance of early stage Antarctic sea urchins (Sterechinus neumayeri) reared under present-day and future pCO2 and temperature. Polar biology, 37(7), 967-980 (2014)

Kapsenberg, L., Kelley, A.L., Shaw, E.C., Martz, T.R. & Hofmann, G.E. Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments. Sci. Rep. 5, 9638; DOI:10.1038/srep09638 (2015).

Matson, P.G., T.R. Martz and G.E. Hofmann. "High frequency observations of pH under Antarctic sea ice in the southern Ross Sea.," Antarctic Science, v.23, 2011, p. 607.

Sewell, M.A., G.E. Hofmann. "Antarctic echinoids and climate change: a major impact on brooding forms.," Global Change Biology, v.17, 2011, p. 734.

Yu, P.C., P.G. Matson, T.R. Martz and G.E. Hofmann. "The ocean acidification seascape and its relationship to the performance of calcifying marine invertebrates: laboratory experiments on the development of urchin larvae framed by environmentally-relevant pCO2/pH," J. Exp. Mar. Biol. Ecol., v.400, 2011, p. 288.