Oxygen levels in the ocean are expected to decrease as global warming progresses, with potentially serious implications for marine life. To forecast future changes in ocean oxygen levels, a better understanding is needed of deoxygenation associated with past warming events.
This project, a collaboration between researchers at Syracuse and Yale Universities, will use iodine in benthic foraminiferal tests as a novel proxy for past oxygenation conditions. The research is motivated by the a close relationship between redox conditions and iodate (IO3-) concentrations in seawater, which affect I/Ca values in foraminiferal tests. The project will expand upon preliminary work in order to better calibrate the iodine proxy, then apply it to a study of the Paleocene-Eocene Thermal Maximum (PETM), a warming event that occurred ~55 million years ago. The researchers will reconstruct temporal, bathymetric, and geographic variations in ocean oxygenation during the PETM, using benthic foraminifera in cores collected by the Ocean Drilling Program from the Atlantic, Pacific, and Indian Ocean basins, as well as land sections from the Mediterranean, eastern U.S., and New Zealand. In addition, they will examine the link between deoxygenation and benthic extinctions, and consider patterns of hypoxia/anoxia to assess which factors (e.g., temperature, productivity, circulation, local methane oxidation) most influenced the development of low oxygen conditions.
The researchers will collaborate internationally on proxy refinement with institutions in Germany (GEOMAR) and the UK (Oxford), and will engage policy makers through venues like the Yale Climate and Energy Institute. Funding will support an early-career investigator; additionally, the project will train one PhD, one MS, and two undergraduate students. The project will involve underrepresented high school students through EVOLUTIONS, an NSF-funded after-school program at the Peabody Museum (Yale). Results will be incorporated into university coursework and exhibits targeted at undergraduates.
