Abstract
Increasing reactive nitrogen (Nr) deposition in the Arctic may adversely impact N-limited ecosystems. To investigate atmospheric transport of Nr 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 (δ
15N and δ
18O) 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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Acknowledgements
The authors thank the ice-coring teams and NPI for field logistical support. J. Kohler (NPI) and T.V. Schuler (University of Oslo) kindly provided the AWS data. This study was supported within the Marie Curie Initial Training Network NSINK ITN-2007.1.1, ENV. 215503, with additional support from NPI, Stiftelsen Ymer-80 and the Geographical Society of Uppsala, Sweden. This is a contribution to the Cryosphere–Atmosphere Interactions in a Changing Arctic Climate Top-level Research Initiative and to the EU Regional Development Foundation, project 3.2.0801.12-0044. Insightful comments by two anonymous referees improved the manuscript. At the time of this research, MPB was working at the Norwegian Polar Institute, Fram Centre, P.O. Box 6606 Langnes, NO-9296 Tromsø, Norway.
Notes
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