Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Evening Poster

M (Multidisciplinary and Interdisciplinary) » M-TT Technology & Techniques

[M-TT37] Frontiers in Geochemistry

Sun. May 20, 2018 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Urumu Tsunogai(Graduate School of Environmental Studies, Nagoya University), Yoshio Takahashi(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Tsuyoshi Iizuka(東京大学)

[MTT37-P05] Challenges in quantifying triple oxygen isotopic compositions of nitrate in subtropical surface oceans

*Peng Weiqing1, Yoshiumi Matsumoto1, Chiho Sukigara1, Masanori Ito1, Fumiko Nakagawa1, Urumu Tsunogai1 (1.Graduate School of Environmental Studies, Nagoya University)

Keywords:nitrate, triple oxygen isotopic compositions, surface seawater, subtropical ocean

In this study, we challenged to quantify triple oxygen isotopic composition (17O-excess) of nitrate in nutrient-poor subtropical surface seawater. 17O-excess of low level nitrate in the water sample has been determined by adding nitrate standard of already-known oxygen isotopic compositions in each sample. By using this internal standard method, we successfully determined the 17O-excess of dissolved nitrate in surface seawater with its concentration ranging from 0.1 to 0.5 μmol/L and observed high 17O-excess of +4.7±2‰ in dissolved nitrate of surface seawater samples collected in the western north pacific. The result indicates that atmospheric nitrate deposited on the surface seawater account for 10%~25% of the total dissolved nitrate in the samples.