Bioavailability of Iron contained in Nanoparticles of Glacial Origin

The Southern Ocean is a key player for the control of atmospheric CO2 and therefore climate. However the biological pump of CO2 in this ocean is severely limited by the availability of iron for phytoplankton. But a few oasis exist where enhanced biological activity results from natural iron fertilization. These regions are excellent natural laboratories and the Plateau of Kerguelen and the waters extending eastward are a good example. BINGO2 aims to investigate a so far unexplored issue in this region: the role of glacier melting as iron source for the ocean. BINGO2 proposes a study focused glaciers located in different geological environments. The challenge will be to detect iron nanoparticles in the melting water of the glacier and to evaluate their bioavailability for phytoplankton. BINGO2 relies on expeditions at Kerguelen where we will first collect the particles in the vicinity of glaciers and second we will test the availability of these particles for iron limited marine microbial communities at Port aux Français. Investigations conducted both from a geochemical and biological perspective will provide original results that will contribute to better understand the future of the Southern Ocean considering the accelerated melting of ice caps.