Ocean acidification in a California upwelling zone: A sentinel site for impacts on open-coast and estuarine foundation species

University Of California-Davis, Davis CA

Investigators

Abstract

The absorption of human-produced CO2 into the oceans is decreasing seawater pH and causing marked declines in the saturation state for calcium carbonate, a major building block for shells, skeletons, and tests of many marine species. Such changes (collectively termed "ocean acidification") have the potential to devastate a broad array of organisms, both at the level of individuals and at population and ecosystem scales. Although awareness of these issues is rapidly growing, most of what is known is based on studies of coral reef organisms and plankton. This project will enhance understanding of impacts from ocean acidification by providing rigorous data on several new fronts applicable to temperate systems. The project will operate within one of the strongest upwelling centers of the eastern Pacific, where global trends in acidification are amplified by the presence of cold water characterized by already-high levels of aqueous CO2. Using an integrated, comparative approach that exploits the expertise of oceanographers, marine chemists, and biologists, the investigators will explicitly couple moored and shipboard measurements of seawater chemistry to controlled laboratory and field studies of biological responses. Two vital foundation species (the California mussel, Mytilus californianus, and the Olympia oyster, Ostrea conchaphila) will be targeted. These two species play disproportionately important roles in open-coast and estuarine systems, respectively. Larvae (which are often the most vulnerable stages) of mussels and oysters will be cultured under elevated-CO2 conditions through the full pelagic period and into juvenile life. Growth and survivorship will be quantified, and water temperature and salinity will be varied to test for interactive effects of multiple factors. Intraspecific variation in response of larvae from different parental lineages will be examined. 'Carry-over?' effects that originate from exposure during the larval stage, but influence subsequent juvenile growth and survival, will be determined both in the laboratory and using field outplants. Because larval and juvenile stages play important roles as demographic age-structure bottlenecks, overall population consequences will be estimated through comparison of observed impacts on early life stages to other recognized sources of recruitment variation. Oceanographic sampling conducted as part of the study will provide a unique baseline data set of the carbonate system within an intense upwelling system, and will extend an existing decade-scale record of pH in a local estuary. The sampling will also be integrated into a developing, larger scale ocean acidification monitoring network involving other researchers distributed along the west coast of North America. In the educational realm, the study will provide interdisciplinary training and research experience for a graduate student, and will create unique opportunities for students from under-represented (especially Latino) groups via links to Bodega Marine Laboratory?s successful REU program and publicly accessible summer curriculum. Findings will be incorporated into a new NSF-funded Graduate/K-12 program at BML, as well as its public education program, which is highly active and reaches more than 10,000 people each year. In outreach arenas beyond BML, the project team will work with a nonprofit organization to lead secondary teacher workshops and build interactive displays that bring scientific concepts directly to middle school students. At the level of the university and in academia more generally, research findings will be incorporated into undergraduate and graduate courses, and will be disseminated to scientists, resource managers, and the general public via traditional professional venues.