Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer
Here we report the measurement of the comprehensive isotopic composition (δ15N, Δ17O and δ18O) of nitrate at the air–snow interface at Dome C, Antarctica (DC, 75°06' S, 123°19' E), and in snow pits along a transect across the East Antarctic Ice Sheet (EAIS) between 66° S and 78° S. In most...
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Copernicus Publications on behalf of the European Geosciences Union
2013
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Online Access: | http://nora.nerc.ac.uk/id/eprint/502987/ https://nora.nerc.ac.uk/id/eprint/502987/1/acp-13-6403-2013.pdf https://doi.org/10.5194/acp-13-6403-2013 |
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ftnerc:oai:nora.nerc.ac.uk:502987 2023-05-15T13:48:07+02:00 Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer Erbland, J. Vicars, W. C. Savarino, J. Morin, S. Frey, M. M. Frosini, D. Vince, E. Martins, J. M. F. 2013-07 text http://nora.nerc.ac.uk/id/eprint/502987/ https://nora.nerc.ac.uk/id/eprint/502987/1/acp-13-6403-2013.pdf https://doi.org/10.5194/acp-13-6403-2013 en eng Copernicus Publications on behalf of the European Geosciences Union https://nora.nerc.ac.uk/id/eprint/502987/1/acp-13-6403-2013.pdf Erbland, J.; Vicars, W. C.; Savarino, J.; Morin, S.; Frey, M. M. orcid:0000-0003-0535-0416 Frosini, D.; Vince, E.; Martins, J. M. F. 2013 Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer. Atmospheric Chemistry and Physics, 13 (13). 6403-6419. https://doi.org/10.5194/acp-13-6403-2013 <https://doi.org/10.5194/acp-13-6403-2013> Chemistry Publication - Article PeerReviewed 2013 ftnerc https://doi.org/10.5194/acp-13-6403-2013 2023-02-04T19:37:34Z Here we report the measurement of the comprehensive isotopic composition (δ15N, Δ17O and δ18O) of nitrate at the air–snow interface at Dome C, Antarctica (DC, 75°06' S, 123°19' E), and in snow pits along a transect across the East Antarctic Ice Sheet (EAIS) between 66° S and 78° S. In most of the snow pits, nitrate loss (either by physical release or UV photolysis of nitrate) is observed and fractionation constants associated are calculated. Nitrate collected from snow pits on the plateau (snow accumulation rate below 50 kg m−2 a−1) displays average fractionation constants of (−59±10) ‰, (+2.0±1.0) ‰ and (+8.7±2.4)‰ for δ15N, Δ17O and δ18O, respectively. In contrast, snow pits sampled on the coast show distinct isotopic signatures with average fractionation constants of (−16±14) ‰, (−0.2±1.5) ‰ and (+3.1±5.8) ‰, for δ15N, Δ17O and δ18O, respectively. Our observations corroborate that photolysis (associated with a 15N / 14N fractionation constant of the order of –48 ‰ according to Frey et al. (2009) is the dominant nitrate loss process on the East Antarctic Plateau, while on the coast the loss is less pronounced and could involve both physical release and photochemical processes. Year-round isotopic measurements at DC show a~close relationship between the Δ17O of atmospheric nitrate and Δ17O of nitrate in skin layer snow, suggesting a photolytically driven isotopic equilibrium imposed by nitrate recycling at this interface. Atmospheric nitrate deposition may lead to fractionation of the nitrogen isotopes and explain the almost constant shift of the order of 25 ‰ between the δ15N values in the atmospheric and skin layer nitrate at DC. Asymptotic δ15N(NO3−) values calculated for each snow pit are found to be correlated with the inverse of the snow accumulation rate (ln(δ15N as. + 1) = (5.76±0.47) ċ (kg m−2 a−1/ A) + (0.01±0.02)), confirming the strong relationship between the snow accumulation rate and the degree of isotopic fractionation, consistent with previous observations by Freyer et al. (1996). Asymptotic ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Natural Environment Research Council: NERC Open Research Archive Antarctic East Antarctic Ice Sheet Atmospheric Chemistry and Physics 13 13 6403 6419 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
topic |
Chemistry |
spellingShingle |
Chemistry Erbland, J. Vicars, W. C. Savarino, J. Morin, S. Frey, M. M. Frosini, D. Vince, E. Martins, J. M. F. Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
topic_facet |
Chemistry |
description |
Here we report the measurement of the comprehensive isotopic composition (δ15N, Δ17O and δ18O) of nitrate at the air–snow interface at Dome C, Antarctica (DC, 75°06' S, 123°19' E), and in snow pits along a transect across the East Antarctic Ice Sheet (EAIS) between 66° S and 78° S. In most of the snow pits, nitrate loss (either by physical release or UV photolysis of nitrate) is observed and fractionation constants associated are calculated. Nitrate collected from snow pits on the plateau (snow accumulation rate below 50 kg m−2 a−1) displays average fractionation constants of (−59±10) ‰, (+2.0±1.0) ‰ and (+8.7±2.4)‰ for δ15N, Δ17O and δ18O, respectively. In contrast, snow pits sampled on the coast show distinct isotopic signatures with average fractionation constants of (−16±14) ‰, (−0.2±1.5) ‰ and (+3.1±5.8) ‰, for δ15N, Δ17O and δ18O, respectively. Our observations corroborate that photolysis (associated with a 15N / 14N fractionation constant of the order of –48 ‰ according to Frey et al. (2009) is the dominant nitrate loss process on the East Antarctic Plateau, while on the coast the loss is less pronounced and could involve both physical release and photochemical processes. Year-round isotopic measurements at DC show a~close relationship between the Δ17O of atmospheric nitrate and Δ17O of nitrate in skin layer snow, suggesting a photolytically driven isotopic equilibrium imposed by nitrate recycling at this interface. Atmospheric nitrate deposition may lead to fractionation of the nitrogen isotopes and explain the almost constant shift of the order of 25 ‰ between the δ15N values in the atmospheric and skin layer nitrate at DC. Asymptotic δ15N(NO3−) values calculated for each snow pit are found to be correlated with the inverse of the snow accumulation rate (ln(δ15N as. + 1) = (5.76±0.47) ċ (kg m−2 a−1/ A) + (0.01±0.02)), confirming the strong relationship between the snow accumulation rate and the degree of isotopic fractionation, consistent with previous observations by Freyer et al. (1996). Asymptotic ... |
format |
Article in Journal/Newspaper |
author |
Erbland, J. Vicars, W. C. Savarino, J. Morin, S. Frey, M. M. Frosini, D. Vince, E. Martins, J. M. F. |
author_facet |
Erbland, J. Vicars, W. C. Savarino, J. Morin, S. Frey, M. M. Frosini, D. Vince, E. Martins, J. M. F. |
author_sort |
Erbland, J. |
title |
Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
title_short |
Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
title_full |
Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
title_fullStr |
Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
title_full_unstemmed |
Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer |
title_sort |
air–snow transfer of nitrate on the east antarctic plateau - part 1: isotopic evidence for a photolytically driven dynamic equilibrium in summer |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2013 |
url |
http://nora.nerc.ac.uk/id/eprint/502987/ https://nora.nerc.ac.uk/id/eprint/502987/1/acp-13-6403-2013.pdf https://doi.org/10.5194/acp-13-6403-2013 |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_relation |
https://nora.nerc.ac.uk/id/eprint/502987/1/acp-13-6403-2013.pdf Erbland, J.; Vicars, W. C.; Savarino, J.; Morin, S.; Frey, M. M. orcid:0000-0003-0535-0416 Frosini, D.; Vince, E.; Martins, J. M. F. 2013 Air–snow transfer of nitrate on the East Antarctic Plateau - Part 1: Isotopic evidence for a photolytically driven dynamic equilibrium in summer. Atmospheric Chemistry and Physics, 13 (13). 6403-6419. https://doi.org/10.5194/acp-13-6403-2013 <https://doi.org/10.5194/acp-13-6403-2013> |
op_doi |
https://doi.org/10.5194/acp-13-6403-2013 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
13 |
container_issue |
13 |
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6403 |
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6419 |
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1766248670294966272 |