Nitrate stable isotopes in snow and ice samples from four Svalbard sites

Abstract

Increasing reactive nitrogen (N_r) deposition in the Arctic may adversely impact N-limited ecosystems. To investigate atmospheric transport of N_r to Svalbard, Norwegian Arctic, snow and firn samples were collected from glaciers and analysed to define spatial and temporal variations (1–10 years) in major ion concentrations and the stable isotope composition (δ¹⁵N and δ¹⁸O) of nitrate () across the archipelago. The and averaged −4‰ and 67‰ in seasonal snow (2010–11) and −9‰ and 74‰ in firn accumulated over the decade 2001–2011. East–west zonal gradients were observed across the archipelago for some major ions (non-sea salt sulphate and magnesium) and also for and in snow, which suggests a different origin for air masses arriving in different sectors of Svalbard. We propose that snowfall associated with long-distance air mass transport over the Arctic Ocean inherits relatively low due to in-transport N isotope fractionation. In contrast, faster air mass transport from the north-west Atlantic or northern Europe results in snowfall with higher because in-transport fractionation of N is then time-limited.

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Keywords: Nitrate; isotopes; ice cores; Svalbard; pollutants.

(Published: 13 April 2015)

Citation: Polar Research 2015, 34, 23246, http://dx.doi.org/10.3402/polar.v34.23246