TERRAPUB Geochemical Journal

Geochemical Journal, Vol. 52 (No. 2), pp. e7-e14, 2018


Spatial variation of isotopic compositions of snowpack nitrate related to post-depositional processes in eastern Dronning Maud Land, East Antarctica

Kazushi Noro,1 Shohei Hattori,2* Ryu Uemura,3 Kotaro Fukui,4 Motohiro Hirabayashi,5 Kenji Kawamura,5 Hideaki Motoyama,5 Norimichi Takenaka1 and Naohiro Yoshida2,6

1Graduate School of Engineering, Osaka Prefecture University, Osaka 599-8531, Japan
2Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Kanagawa 226-8502, Japan
3Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa 903-0213, Japan
4Tateyama Caldera Sabo Museum, Toyama 930-1405, Japan
5National Institute of Polar Research, Tokyo 190-8518, Japan
6Earth-Life Science Institute (ELSI), Tokyo Institute of Technology, Tokyo 152-8550, Japan

(Received November 16, 2017; Accepted January 23, 2018; Online published March 9, 2018)

Abstract: To evaluate post-depositional loss from the snow surface and subsequent redistribution of nitrate, we determined the spatial variation of nitrate concentrations, as well as δ15N and Δ17O values of nitrate in surface snow, sampled along a latitudinal transect in eastern Dronning Maud Land, East Antarctica. The NO3- concentrations of surface snow ranged from 40.0 to 130.8 μg L-1, showing no obvious trends with latitude, while the δ15N(NO3-) in surface snow increased from coastal sites to inland sites, ranging from −19.4 to 165.5‰. The relationship between the isotopic values (δ15N and Δ17O) of nitrate and snow accumulation rate are consistent with other traverses studied in East Antarctica (e.g., from Dumont d'Urville station to Vostok, and from East Antarctic coast to Dome Argus), implying that post-depositional loss and redistribution occur similarly throughout East Antarctica.
Key words: nitrate, photolysis, δ15N, Antarctica, snowpack

*Corresponding author E-mail: hattori.s.ab@m.titech.ac.jp

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