The Olympia Oyster Project \(MS Thesis Project)

Increased concentrations of greenhouse gases in the atmosphere are contributing to global warming and temperatures are projected to increase 2˚C to 4˚C in the next 90 year. In California, mean temperatures are projected to increase 1.7˚C to 8.3˚C over the course of the next century. In addition to warming, global climate change is also projected to affect precipitation. This will result in changes in freshwater run-off from rain and snow-melt into bays and estuaries, and may have additional consequences for organisms inhabiting these environments, specifically Olympia oysters (Ostrea lurida). In dry years in the San Francisco Bay, salinity is predicted to remain relatively stable (~ 22 ppt to 27 ppt); however, salinity in wet years is projected to fluctuate dramatically (~ 4 ppt to 25 ppt) and will be accompanied by an increased frequency of extreme low salinity events during periods of heavy rain. Changes in salinity are also known to affect mitochondrial oxidation rates as well as intermediates of the Krebs cycle; therefore, interactions between cellular response pathways for temperature and salinity might be predicted to affect the ability of oysters to successfully respond to stressful conditions. The mechanisms by which salinity and temperature interact are not straightforward. When presented with elevated temperature in combination with prolonged exposure to low salinity, O. lurida may display a different response than if presented with a single-stressor alone as previous multi-stressor investigations have demonstrated. The objective of this study was to investigate the capacity of O. lurida to tolerate a two-week moderately low salinity (12 ppt) event following acclimation to mean-high (25 ppt) and mean-low (18 ppt) wintertime salinities under current (12˚C) and projected (16˚C) temperatures for the San Francisco Bay. Research was conducted at San Francisco State University's Romberg Tiburon Center for Environmental Science Tiburon, CA.