Japan Geoscience Union Meeting 2016

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Poster

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS17] Paleoclimatology and paleoceanography

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Minoru Ikehara(Center for Advanced Marine Core Research, Kochi University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Ikuko Kitaba(Research Centre for Palaleoclimatology, Ritsumeikan University), Akihisa Kitamura(Institute of Geosciences, Faculty of Science, Shizuoka University), Masaki Sano(Research Institute for Humanity and Nature), Ryuji Tada(Department of Earth and Planetary Science, Graduate School of Science, The Univeristy of Tokyo), Takeshi Nakagawa(Ritsumeikan University), Akira Hayashida(Department of Environmental Systems Science, Doshisha University)

5:15 PM - 6:30 PM

[MIS17-P27] Late Quaternary paleoceanographic changes in the northeastern Arabian Sea;
Inferred from sedimentary organic matter records.

Koudai Yamashita3, *Masafumi MURAYAMA1, Naomi Harada2 (1.Center for Advanced Marine Core Research, Kochi University, 2.Japan Agency for Marine-Earth Science and Technology, 3.Graduate School of Integrated Arts and Sciences, Kochi University)

Keywords:Arabian Sea, organic matter, oxygen minimum zone (OMZ), δ15N

The northeastern Arabian Sea is characterized by a widespread midwater oxygen minimum zone (OMZ), between 80 to 1300 m, with oxygen concentrations reaching values of <0.05 mL/L-1at present. In particular, biogenic particle fluxes in this region have experienced large seasonal changes due to strong monsoonal winds in summer and winter. Here we report carbon and nitrogen isotope data for a sediment core (ER-4) collected from this region. Synchronous downcore variations in the δ15N record, which are explained by regional changes in the isotopic composition of subsurface nitrate, and hence denitrification were found. Moreover, these variations are synchronous with Indian monsoon changes during the glacial-interglacial cycles, thereby establishing a link with global climate. We discuss that these climate linked variations in this region that are likely to have experienced marine biogeochemical cycles during the Late Quaternary.