High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples
An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2) trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we de...
Published in: | Atmospheric Measurement Techniques |
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Copernicus Publications
2014
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00018409 2023-05-15T16:38:59+02:00 High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples Bauska, T. K. Brook, E. J. Mix, A. C. Ross, A. 2014-11 electronic https://doi.org/10.5194/amt-7-3825-2014 https://noa.gwlb.de/receive/cop_mods_00018409 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00018364/amt-7-3825-2014.pdf https://amt.copernicus.org/articles/7/3825/2014/amt-7-3825-2014.pdf eng eng Copernicus Publications Atmospheric Measurement Techniques -- http://www.bibliothek.uni-regensburg.de/ezeit/?2505596 -- http://www.atmospheric-measurement-techniques.net/ -- 1867-8548 https://doi.org/10.5194/amt-7-3825-2014 https://noa.gwlb.de/receive/cop_mods_00018409 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00018364/amt-7-3825-2014.pdf https://amt.copernicus.org/articles/7/3825/2014/amt-7-3825-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/amt-7-3825-2014 2022-02-08T22:53:10Z An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2) trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we describe a new technique to determine the δ13C of CO2 at very high precision, as well as measuring the CO2 and N2O mixing ratios. In this method, ancient air is extracted from relatively large ice samples (~400 g) with a dry-extraction "ice grater" device. The liberated air is cryogenically purified to a CO2 and N2O mixture and analyzed with a microvolume-equipped dual-inlet IRMS (Thermo MAT 253). The reproducibility of the method, based on replicate analysis of ice core samples, is 0.02‰ for δ13C-CO2 and 2 ppm and 4 ppb for the CO2 and N2O mixing ratios, respectively (1σ pooled standard deviation). Our experiments show that minimizing water vapor pressure in the extraction vessel by housing the grating apparatus in a ultralow-temperature freezer (−60 °C) improves the precision and decreases the experimental blank of the method to −0.07 ± 0.04‰. We describe techniques for accurate calibration of small samples and the application of a mass-spectrometric method based on source fragmentation for reconstructing the N2O history of the atmosphere. The oxygen isotopic composition of CO2 is also investigated, confirming previous observations of oxygen exchange between gaseous CO2 and solid H2O within the ice archive. These data offer a possible constraint on oxygen isotopic fractionation during H2O and CO2 exchange below the H2O bulk melting temperature. Article in Journal/Newspaper ice core Niedersächsisches Online-Archiv NOA Atmospheric Measurement Techniques 7 11 3825 3837 |
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English |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Bauska, T. K. Brook, E. J. Mix, A. C. Ross, A. High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
topic_facet |
article Verlagsveröffentlichung |
description |
An important constraint on mechanisms of past carbon cycle variability is provided by the stable isotopic composition of carbon in atmospheric carbon dioxide (δ13C-CO2) trapped in polar ice cores, but obtaining very precise measurements has proven to be a significant analytical challenge. Here we describe a new technique to determine the δ13C of CO2 at very high precision, as well as measuring the CO2 and N2O mixing ratios. In this method, ancient air is extracted from relatively large ice samples (~400 g) with a dry-extraction "ice grater" device. The liberated air is cryogenically purified to a CO2 and N2O mixture and analyzed with a microvolume-equipped dual-inlet IRMS (Thermo MAT 253). The reproducibility of the method, based on replicate analysis of ice core samples, is 0.02‰ for δ13C-CO2 and 2 ppm and 4 ppb for the CO2 and N2O mixing ratios, respectively (1σ pooled standard deviation). Our experiments show that minimizing water vapor pressure in the extraction vessel by housing the grating apparatus in a ultralow-temperature freezer (−60 °C) improves the precision and decreases the experimental blank of the method to −0.07 ± 0.04‰. We describe techniques for accurate calibration of small samples and the application of a mass-spectrometric method based on source fragmentation for reconstructing the N2O history of the atmosphere. The oxygen isotopic composition of CO2 is also investigated, confirming previous observations of oxygen exchange between gaseous CO2 and solid H2O within the ice archive. These data offer a possible constraint on oxygen isotopic fractionation during H2O and CO2 exchange below the H2O bulk melting temperature. |
format |
Article in Journal/Newspaper |
author |
Bauska, T. K. Brook, E. J. Mix, A. C. Ross, A. |
author_facet |
Bauska, T. K. Brook, E. J. Mix, A. C. Ross, A. |
author_sort |
Bauska, T. K. |
title |
High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
title_short |
High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
title_full |
High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
title_fullStr |
High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
title_full_unstemmed |
High-precision dual-inlet IRMS measurements of the stable isotopes of CO2 and the N2O / CO2 ratio from polar ice core samples |
title_sort |
high-precision dual-inlet irms measurements of the stable isotopes of co2 and the n2o / co2 ratio from polar ice core samples |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/amt-7-3825-2014 https://noa.gwlb.de/receive/cop_mods_00018409 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00018364/amt-7-3825-2014.pdf https://amt.copernicus.org/articles/7/3825/2014/amt-7-3825-2014.pdf |
genre |
ice core |
genre_facet |
ice core |
op_relation |
Atmospheric Measurement Techniques -- http://www.bibliothek.uni-regensburg.de/ezeit/?2505596 -- http://www.atmospheric-measurement-techniques.net/ -- 1867-8548 https://doi.org/10.5194/amt-7-3825-2014 https://noa.gwlb.de/receive/cop_mods_00018409 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00018364/amt-7-3825-2014.pdf https://amt.copernicus.org/articles/7/3825/2014/amt-7-3825-2014.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/amt-7-3825-2014 |
container_title |
Atmospheric Measurement Techniques |
container_volume |
7 |
container_issue |
11 |
container_start_page |
3825 |
op_container_end_page |
3837 |
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1766029346508636160 |