Tristan Horner
Assistant Scientist
Marine Chemistry & Geochemistry
Woods Hole Oceanographic Institution

Isotopic insights into the drivers of marine barium cycling

Barium is widely used as an oceanographic proxy for deep ocean nutrients, ocean circulation, alkalinity, carbon export, surface runoff, and historical upwelling intensity. While this breadth perhaps reflects the unparalleled utility of barium-based proxies to reconstruct all aspects of ocean chemistry, it is also a sign of potentially misidentified driving processes. Development of the barium isotope ‘toolbox’ now permits testing several of the proposed drivers. I will apply this toolbox for precisely this purpose, and will present results spanning several scales: from the basin-scale processes sustaining oceanographic barium distributions, to the micro-scale mechanisms of barium isotope fractionation during mineral precipitation. Emerging results indicate that the mineral barite is the critical driver of marine barium cycling, a result that I will explore in the context of using barium-based proxies for reconstructing ocean chemistry.

The Earth History and Paleobiology (EHAP) Seminar Series is jointly hosted by OEB and EPS.