VARIATION OF GLACIAL-INTERGLACIAL MARINE SILICON ISOTOPIC COMPOSITIONS AND ITS POSSIBLE IMPLICATIONS—A MODELING STUDY

• Main Authors: Gao, Shuang, Völker, Christoph, Lohmann, Gerrit, Butzin, Martin, Wolf-Gladrow, Dieter
• Format: Conference Object
• Language: unknown
• Published: 2014
• Subjects: Southern Ocean
• Online Access: https://epic.awi.de/id/eprint/35332/; http://www.sgmeet.com/osm2014/viewabstract.asp?AbstractID=16048; https://hdl.handle.net/10013/epic.43334

Silicon isotopic composition (δ30Si) is a promising proxy for reconstruction of marine silicic acid utilization and Si cycling in the geological past. It has been applied extensively in the Southern Ocean in order to investigate the glacial-interglacial physical and biological cycles and the pCO2 variations. Our aim is to compare the glacial-interglacial δ30Si distributions of silicic acid and biogenic opal in the oceans and in marine sediments and to further evaluate the influence on δ30Si by the glacial-interglacial variations of ocean circulation, dust deposition, riverine Si flux and its δ30Si. To simulate the Si biogeochemical cycle and Si isotopic compositions under the Last Glacial Maximum (LGM) conditions, we applied the Ocean General Circulation Model (MPI-OM) under the LGM atmospheric forcing and dust deposition and applied the Hamburg Ocean Carbon Cycle Model (HAMOCC5.1) which includes an interactive sediment module. Finally, the pre-industrial and glacial water masses are identified and the Si cycling (including δ30Si) is compared to proxy data.