Online deposition over oceans: modeling the effect of air pollution on ocean bio-geochemistryin an earth system model
Iron (Fe) deposition from dust and combustion aerosols is essential for the marine primary productivity in large portions of the world ocean, where phytoplankton growth mitigates part of the anthropogenic CO2 emissions. Under polluted conditions, the atmospheric acidity and organic ligands dramatically enhance aerosol Fe-mobilization, perturbing also the marine CO2 uptake capacity upon aerosol Fe deposition. Air-quality regulations, designed to decrease future atmospheric pollution, will consequently moderate the dissolved Fe deposition flux over oceans and change its pattern. However, the effect of air pollution on the bioavailable Fe supply into the oceans and their primary productivity remains largely ambiguous, with a likely but poorly known climatic impact. The ODEON project will address this long-standing research question by performing for the first time coupled atmosphere-ocean-climate simulations with the European Earth System Model (ESM) EC-Earth, focused on the impacts of Fe deposition on the oceanic carbon-cycle. Recently, important advances were made by the applicant in understanding aerosol Fe dissolution and emission processes. However, ESMs still use simplified parameterizations and asynchronous coupling of Fe supply to the marine biogeochemistry, inserting severe uncertainties in the response of the carbon-cycle to anthropogenic emissions. ODEON aims to improve this situation by developing modelling tools beyond-state-of-the-art, to simulate the atmospheric Fe-cycle in EC-Earth coupled to the embedded ocean biogeochemistry model. The future fellow’s strong atmospheric chemistry modelling background, together with the advanced training-through-research plan on cutting-edge and multi-disciplinary EMS techniques, ensures the feasibility of this project. ODEON’s training scheme in climate modelling, ocean biogeochemistry and interaction with science-users will contribute to the applicant’s development as an independent and interdisciplinary researcher.