Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios
In 2012, an unexpected CH4 excess has been reported above open leads in the Arctic Ocean showing that sea ice plays a role in the ocean-atmosphere CH4 dynamics. However, the processes involved there have not yet been identified. We performed CH4 stable isotope (d13C and dD) analyses on sea ice sampl...
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ftorbi:oai:orbi.ulg.ac.be:2268/232383 2024-04-21T07:52:32+00:00 Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios Sapart, C. Jacques, Caroline Carnat, Gauthier Zhou, Jiayun Delille, Bruno Niemann, H. Röckmann, T. van der Veen, C. Tison, J.-L. 2018-06-20 https://orbi.uliege.be/handle/2268/232383 en eng https://orbi.uliege.be/handle/2268/232383 info:hdl:2268/232383 Open Science Conference POLAR2018, Davos, Switzerland [CH], 18-23 June 2018 Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique conference poster not in proceedings http://purl.org/coar/resource_type/c_18co info:eu-repo/semantics/conferencePoster 2018 ftorbi 2024-03-27T14:49:36Z In 2012, an unexpected CH4 excess has been reported above open leads in the Arctic Ocean showing that sea ice plays a role in the ocean-atmosphere CH4 dynamics. However, the processes involved there have not yet been identified. We performed CH4 stable isotope (d13C and dD) analyses on sea ice samples, as well as geochemical and physical measurements, to determine the possible pathways involved in CH4 production/removal in or under sea ice. We present results from ice cores collected above the shallow shelf of Barrow (Alaska) from January to June 2009 as well as in the landfast ice of McMurdo Sound (Antarctica) from September to November 2012. We found a clear difference in isotopic signature between the two sites. The McMurdo ice was supersaturated in CH4 and showed isotopic signatures surprisingly enriched in heavy isotopes (d13C between -47 and -12 ‰ and dD between -87 and -350‰). No natural pathways have yet been identified with such isotopic signatures, but we suggest that aerobic CH4 formation in or under the ice might be a candidate. In contrast, the CH4 concentrations were much larger in ice overlying the shallow shelf of Barrow and there the origin of CH4 was clearly biogenic (d13C between -48 and -68 ‰ and dD between -180 and -250‰), thus likely originating from the sediment. In the McMurdo ice, the seasonal evolution shows that CH4 was becoming more enriched in heavy isotopes with time, suggesting the occurrence of aerobic oxidation processes in the ice. Conference Object Antarc* Antarctica Arctic Ocean Barrow McMurdo Sound Sea ice Alaska University of Liège: ORBi (Open Repository and Bibliography) |
institution |
Open Polar |
collection |
University of Liège: ORBi (Open Repository and Bibliography) |
op_collection_id |
ftorbi |
language |
English |
topic |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique |
spellingShingle |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique Sapart, C. Jacques, Caroline Carnat, Gauthier Zhou, Jiayun Delille, Bruno Niemann, H. Röckmann, T. van der Veen, C. Tison, J.-L. Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
topic_facet |
Physical chemical mathematical & earth Sciences Earth sciences & physical geography Physique chimie mathématiques & sciences de la terre Sciences de la terre & géographie physique |
description |
In 2012, an unexpected CH4 excess has been reported above open leads in the Arctic Ocean showing that sea ice plays a role in the ocean-atmosphere CH4 dynamics. However, the processes involved there have not yet been identified. We performed CH4 stable isotope (d13C and dD) analyses on sea ice samples, as well as geochemical and physical measurements, to determine the possible pathways involved in CH4 production/removal in or under sea ice. We present results from ice cores collected above the shallow shelf of Barrow (Alaska) from January to June 2009 as well as in the landfast ice of McMurdo Sound (Antarctica) from September to November 2012. We found a clear difference in isotopic signature between the two sites. The McMurdo ice was supersaturated in CH4 and showed isotopic signatures surprisingly enriched in heavy isotopes (d13C between -47 and -12 ‰ and dD between -87 and -350‰). No natural pathways have yet been identified with such isotopic signatures, but we suggest that aerobic CH4 formation in or under the ice might be a candidate. In contrast, the CH4 concentrations were much larger in ice overlying the shallow shelf of Barrow and there the origin of CH4 was clearly biogenic (d13C between -48 and -68 ‰ and dD between -180 and -250‰), thus likely originating from the sediment. In the McMurdo ice, the seasonal evolution shows that CH4 was becoming more enriched in heavy isotopes with time, suggesting the occurrence of aerobic oxidation processes in the ice. |
format |
Conference Object |
author |
Sapart, C. Jacques, Caroline Carnat, Gauthier Zhou, Jiayun Delille, Bruno Niemann, H. Röckmann, T. van der Veen, C. Tison, J.-L. |
author_facet |
Sapart, C. Jacques, Caroline Carnat, Gauthier Zhou, Jiayun Delille, Bruno Niemann, H. Röckmann, T. van der Veen, C. Tison, J.-L. |
author_sort |
Sapart, C. |
title |
Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
title_short |
Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
title_full |
Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
title_fullStr |
Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
title_full_unstemmed |
Understanding the Origin(s) of Methane in Sea Ice Using Stable Isotope Ratios |
title_sort |
understanding the origin(s) of methane in sea ice using stable isotope ratios |
publishDate |
2018 |
url |
https://orbi.uliege.be/handle/2268/232383 |
genre |
Antarc* Antarctica Arctic Ocean Barrow McMurdo Sound Sea ice Alaska |
genre_facet |
Antarc* Antarctica Arctic Ocean Barrow McMurdo Sound Sea ice Alaska |
op_source |
Open Science Conference POLAR2018, Davos, Switzerland [CH], 18-23 June 2018 |
op_relation |
https://orbi.uliege.be/handle/2268/232383 info:hdl:2268/232383 |
_version_ |
1796935758413561856 |