Control mechanisms for the oceanic distribution of silicon isotopes

• Published in: Global Biogeochemical Cycles
• Main Authors: Wischmeyer, André G., de La Rocha, Christina, L., Maier-Reimer, Ernst, Wolf-Gladrow, Dieter
• Other Authors: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2003
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Pacific; Southern Ocean
• Online Access: https://hal.univ-brest.fr/hal-00467272; https://hal.univ-brest.fr/hal-00467272/document; https://hal.univ-brest.fr/hal-00467272/file/Wischmeyer_et_al_2003.pdf; https://doi.org/10.1029/2002GB002022

International audience Marine diatoms take up silicic acid for the buildup of their opaline shells and discriminate against the heavier silicon isotope. For the first time, the overall oceanic distribution of silicon isotopes has been estimated by integration of the Hamburg Model of the Ocean Carbon Cycle, version 4 (HAMOCC4). It is shown that the relationship between the silicic acid concentration and its silicon isotope composition is not a simple Rayleigh distillation curve. Only the Southern Ocean and the equatorial Pacific show a clear functional dependency similar to the Rayleigh distillation curve. Model results can be used to predict opal silicon isotope compositions in the sediment and constrain the use of silicon isotopes as a proxy for silicic acid utilization. Owing to the structure of the Pacific current system, it might be valid to apply a relationship between surface silicic acid concentrations and the silicon isotope signal in the equatorial Pacific sediments.