TONGA cruise DNA nifH sequences

The goal of the TONGA cruise is to develop a dedicated strategy involving hydrothermal plume tracers detection (3He, CH4, CO2, Mn, Fe, Si...) to 1) accurately quantify Fe (and other chemicals) input from shallow volcanoes and associated hydrothermalism (hereafter referred to as hydrothermal Fe) along the Tonga volcanic arc between 20 and 25oS for the upper mixed layer, 2) study the fate of Fe plumes in the water column at the local and regional scales, and 3) investigate the potential impact of such Fe input on planktonic communities and biogeochemical cycles in the WTSP. To achieve this goal, we propose the multidisciplinary approach described below involving hydrothermal geochemists, physical oceanographers, trace element chemists (ocean and atmosphere), biogeochemists, biologists and modelers.