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

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 ma...

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Bibliographic Details
Published in:Polar Research
Main Authors: Carmen P. Vega, Mats P. Björkman, Veijo A. Pohjola, Elisabeth Isaksson, Rickard Pettersson, Tõnu Martma, Alina Marca, Jan Kaiser
Format: Article in Journal/Newspaper
Language:English
Published: Norwegian Polar Institute 2015
Subjects:
geo
Online Access:https://doi.org/10.3402/polar.v34.23246
https://doaj.org/article/90f3afb1c7a74a2db0a361c8da1f62b0
Description
Summary: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 (δ15N and δ18O) of nitrate (NO3-) across the archipelago. The δ15N NO3- and δ18ONO3- 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 δ15NNO3- and δ18ONO3- 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 δ15NNO3- 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 δ15NNO3- because in-transport fractionation of N is then time-limited.