"Iron (Fe) is now recognized as a limiting nutrient in large regions of world’s ocean and changes in the supply of Fe to the upper ocean may lead to climate change by affecting biological productivity and altering rates of carbon sequestration. However, there is a continuing debate over the sources of dissolved Fe to the global ocean. Therefore, it is difficult to predict how climate-driven changes in weathering and coastal hypoxia might impact future Fe delivery to the global ocean. In this project, the applicant aims to apply a promising new technique for measuring Fe isotopes in seawater in order to determine if oceanic Fe sources derived from benthic diagenesis or seafloor hydrothermal systems have characteristic isotope signatures that are distinct from riverine or atmospheric Fe sources. In order to test this hypothesis, the applicant will investigate four contrasted region of the world’s ocean, including (1) seafloor hydrothermal plume from the mid-Atlantic ridge at 5°S (2-3) oxygen minimum zones in the Pacific affected by either hydrothermal input from Loihi Seamount or shelf input from the Peru Margin and (4) Atlantic zonal section affected by variable dust deposition. This study will involve international collaborations with US and EU scientists and the results will be integrated in the context of the Geotraces and InterRidge international programs. The applicant is expecting to return in France in September 2009 to hold a 3-years term position at the European Institute of Marine Studies (IUEM) in France. By providing the necessary resources, this project will strengthen the competitiveness of the host institution in this rapidly evolving research field and will enhance the reintegration of the applicant in the EU scientific community."