Collaborative Research: Glacial deep Pacific carbon storage and effects on CaCO3 preservation

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The oceans are threatened by climate change, and understanding how they will respond to higher CO2 levels has never been more important. Past changes in the ocean’s carbon cycle can provide data to check and improve models that help us predict future changes. These data can also help us ‘balance’ Earth’s carbon budget by showing where and how much carbon was stored in the ocean at times when the Earth has been much colder. Research will be carried out by two early career, female scientists and includes roles for college and graduate students. This work also increases access to information about climate change by creating activities for high school classrooms. This work advances discovery, integrates research and education, increases the participation of underrepresented groups in the geosciences, and fosters the inclusion of the public in fundamental science research. This project is jointly funded by OCE-Marine Geology and Geophysics (OCE-MGG) and the Established Program to Stimulate Competitive Research (EPSCoR).Despite the importance of understanding whole-ocean carbon system changes in glacial periods, and the volumetric dominance of the Pacific Ocean, the Atlantic Ocean has been the primary locus of most quantitative carbon cycle reconstructions. This means that longstanding questions about Pacific carbon storage and dissolution feedbacks remain largely unanswered. The Pacific Ocean’s carbon budget in the past will be explored using several geochemical proxies. The B/Ca ratio of benthic foraminifera is a state-of-the-art proxy for examining these questions, as it records the difference between seawater’s carbonate ion concentration and its concentration at saturation Delta[CO32-]. The research plan pairs this new proxy with classical methods of reconstructing carbon cycle changes in the deep ocean including planktonic foraminifera species assemblages and individual weights, calcium carbonate fluxes, carbon isotope analysis of benthic foraminifera, and reconstructions of organic carbon fluxes (Baxs). The multiproxy approach is designed to constrain different carbon cycle feedbacks, and to calibrate less expensive microscope-based techniques in an effort to harness the wealth of existing paleoclimate datasets for quantitative reconstructions and model-data cross validation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.