The critical role of sedimentary trace element fluxes in ocean biogeochemistry

ended

Trace elements and isotopes (TEIs) are powerful tools for studying the ocean system and tracing its interaction with the other Earth System components. Many TEIs exert influence on the surface environment by participating in the global carbon and oxygen cycles. Incorporating TEIs into state-of-the-art global models is thus crucial to better predict future changes of ocean biogeochemistry and climate. This effort, however, is hampered by our limited understanding of the source and sink fluxes of TEIs across the sediment-water interface, which are recently hypothesised to play much greater roles in setting the distributions of TEIs in the ocean than previously assumed. Yet insufficient knowledge results in large uncertainties in model implementations of sedimentary fluxes, severely limiting the applications of marine TEIs. The objectives of SedTraceFlux are to constrain the sedimentary TEI fluxes and provide robust parameterizations of such fluxes suitable for global models. This project will focus on iron, neodymium, zinc and their respective isotopes, which are among the most useful TEI tools in oceanography. I will model the chemical speciation and the processes controlling the distributions of these TEIs in sediment pore water and solid phases. The resulting mechanistic parameterizations of sedimentary fluxes will be fine-tuned using Transport Matrix Methods in global biogeochemical modelling. The modelling effort will be complemented by generation of sedimentary Fe data from under-sampled locations. This project represents an ideal synergy between my ability in geochemical modelling and sediment geochemistry, and the expertise of the host group in a broad range of chemical, isotopic and global modelling approaches. It will enhance my innovative potential toward an independent researcher and strengthen the host’s international network and mobility. The results will also help inform the ocean and climate policy-making of the European Union.