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

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.