Joan M. Bernhard

Effects of carbon dioxide disposal on deep-sea foraminifers

Jim Kennett (University of California, Santa Barbara); Jim Barry (Monterey Bay Aquarium Research Institute)

One potential mechanism to alleviate global warming due to greenhouse gases is to sequester carbon dioxide in the deep sea, but the effects of such disposal on the resident fauna are not well understood. Along with colleagues (Jim Kennett, University of California Santa Barbara; Jim Barry, Monterey Bay Aquarium Research Institute), my lab is funded by the Department of Energy to determine the effects of deep-sea CO2 disposal on benthic foraminifera. A month-long CO2-release experiment was conducted using MBARI?s ROV Tiburon from December 2004 to January 2005. Because necrotic foraminiferal cytoplasm can remain in a foraminiferal shell for weeks (see Bernhard 2000 Micropaleontology for review), which is the time frame of our experiment, we used a fluorescent labeling approach to identify live foraminifera. Cores were incubated in a fluorogenic probe that is dependent on hydrolytic enzyme activity (Cell Tracker Green CMFDA, Molecular Probes, Eugene OR). To avoid any potential negative effects from temperature and pressure changes associated with collection, incubations were executed on the seafloor prior to core collection and fixation, and approach that has not previously been attempted. Although samples are still being analyzed, we know the incubations worked. Laboratory experiments on foraminiferal survival in response to elevated CO2 and decreased pH were conducted by Liz Mollo-Christensen, an undergraduate from Colby College, and Nadine Eisenkolb, an undergraduate from the University of Hawaii. A manuscript describing initial results was recently submitted for publication. If you are interested in this project, check back soon-- we may be looking for a new graduate student to conduct laboratory experiments to determine the effect of predicted increases in pCO2 on Scandinavian, temperate and tropical benthic foraminiferal survival and shell morphology.

Last updated: December 18, 2013