Title: " Awesome OCIMs: Ocean Circulation Inverse Models for understanding the global biogeochemical cycling of metals in the ocean"
Abstract: Trace metals such as zinc (Zn) and cadmium (Cd) are oceanographically important elements, both as micronutrients for phytoplankton and as tracers of biology in the modern and ancient ocean. The broad strokes of their distribution have been understood since they were first measured accurately in seawater decades ago, both are obviously drawn down in the surface ocean by phytoplankton and regenerated in the deep ocean. And yet, for just as long there have been mysteries about the details of Zn and Cd cycling. Why does Zn have a distribution which looks like silicate, if it occurs in the soft tissues of plankton instead of in hard silicate frustules? Why is there a slight ‘kink’ in the relationship between Cd and phosphorous at low concentrations, when their deep-ocean distribution is nearly linear? Two recent advances provide insight into such questions. GEOTRACES cruises over the past few years have added thousands of measurements of Zn and Cd concentrations and stable isotopes in the global ocean, while new Ocean Circulation Inverse Models (OCIMs) provide a modeling framework to quickly test various hypotheses about the biogeochemical modeling of these elements.