Yi Wang
Yi Wang is an Assistant Professor at Department of Earth & Environmental Sciences, Tulane University. As a paleoceanographer and geochemist, her research has been focused on using various proxies (e.g., redox-sensitive metals, metal isotopes, etc) to understand past ocean oxygen changes, and their interactions with marine productivity, ocean circulation, and ocean temperature changes caused by climate shifts on various timescales. She received her B.S. from Xiamen University in 2014, and her Ph.D. from University of Michigan in 2020. Prior to joining Tulane, she was a Postdoctoral Investigator at Woods Hole Oceanographic Institution.
Tracking Global Ocean Oxygen with Thallium Isotopes
Yi Wang, Fang Qian, Kassandra Costa, and Sune Nielsen
Ocean oxygenation is closely linked with climate, productivity, and ocean circulation, and plays an important role in modulating nutrient cycles (e.g., carbon and nitrogen). Because of the stoichiometric link between respired carbon accumulation and oxygen consumption, ocean dissolved oxygen can also provide insights on marine carbon storage changes through time. However, currently available ocean oxygen proxy records (e.g., foraminiferal assemblages and trace metals, redox-sensitive metals, and carbon isotopic composition records) are influenced by local factors like ventilation and/or export of organic matter to the sediments, making it challenging to determine the average global state of ocean oxygen and the controlling mechanisms on various timescales. I will focus on the thallium (Tl) isotope system as a promising proxy to reconstruct globally integrated ocean oxygen content via tracking the global manganese (Mn) oxide burial. Our recent core top calibration has shown that authigenic Tl isotope records preserved in low-oxygen environments are able to record the seawater Tl isotopic compositions, opening a new door for investigating global ocean oxygen variations on various timescales. Through case studies, I will highlight how Tl isotopes can track global ocean oxygen reservoir on millennial to longer timescales, which could be modeled through non-steady-state changes driven by rapid perturbations of Mn oxide burial. With more records through the geologic history and future implementation of Tl tracers in the models, Tl isotopes could ultimately become a powerful tool in facilitating better data and model comparisons of ocean oxygen from a global perspective.
