TY - JOUR T1 - Iron from a submarine source impacts the productive layer of the Western Tropical South Pacific (WTSP) A1 - Guieu,Cecile A1 - Bonnet,Sophie A1 - Petrenko,Anne A1 - Menkes,Christophe A1 - Chavagnac,Valerie A1 - Desboeufs,Karine A1 - Maes,Christophe A1 - Moutin,Thierry AD - Sorbonne Univ, CNRS, LOV, F-06230 Villefranche Sur Mer, France. AD - New York Univ Abu Dhabi, Ctr Prototype Climate Modeling, Abu Dhabi, U Arab Emirates. AD - Univ Toulon & Var, Observ Sci Univers Pytheas, Inst Rech Dev,Aix Marseille Univ, CNRS,Inst Natl Sci Univers,MIO, F-13288 Marseille, France. AD - Sorbonne Univ, CNRS, LOCEAN, MNHN,IRD, BP A5, Noumea 98848, New Caledonia. AD - Univ Toulouse, Geosci Environm Toulouse, CNRS, UPS,IRD,CNES, F-31400 Toulouse, France. AD - UPD, UPEC, IPSL, LISA, Creteil, France. AD - Univ Brest, CNRS, IUEM, IRD,LOPS,IFREMER, Brest, France. UR - https://archimer.ifremer.fr/doc/00444/55564/ DO - 10.1038/s41598-018-27407-z N2 - In the Western Tropical South Pacific, patches of high chlorophyll concentrations linked to the occurrence of N2-fixing organisms are found in the vicinity of volcanic islands. The survival of these organisms relies on a high bioavailable iron supply whose origin and fluxes remain unknown. Here, we measured high dissolved iron (DFe) concentrations (up to 66 nM) in the euphotic layer, extending zonally over 10 degrees longitude (174 E−175 W) at ∼20°S latitude. DFe atmospheric fluxes were at the lower end of reported values of the remote ocean and could not explain the high DFe concentrations measured in the water column in the vicinity of Tonga. We argue that the high DFe concentrations may be sustained by a submarine source, also characterized by freshwater input and recorded as salinity anomalies by Argo float in situ measurements and atlas data. The observed negative salinity anomalies are reproduced by simulations from a general ocean circulation model. Submarine iron sources reaching the euphotic layer may impact nitrogen fixation across the whole region. Y1 - 2018/06 PB - Nature Publishing Group JF - Scientific Reports SN - 2045-2322 VL - 8 IS - 1 ID - 55564 ER -