Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada
Methane is over 20 times more effective than CO 2 as a greenhouse gas. Thus, its atmospheric concentration and the processes controlling it are important components of the global climate system. Recent research has shown methanogenesis in subglacial sediments. However, the net contribution from subg...
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2014
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ftmontanastateu:oai:scholarworks.montana.edu:1/9139 2023-05-15T16:21:18+02:00 Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada Spotts, Terra Marie Chairperson, Graduate Committee: Mark L. Skidmore Robertson Glacier (Canada) 2014 application/pdf https://scholarworks.montana.edu/xmlui/handle/1/9139 en eng Montana State University - Bozeman, College of Letters & Science https://scholarworks.montana.edu/xmlui/handle/1/9139 Copyright 2014 by Terra Marie Spotts Methane Glaciers Microbiology Thesis 2014 ftmontanastateu 2022-06-06T07:25:51Z Methane is over 20 times more effective than CO 2 as a greenhouse gas. Thus, its atmospheric concentration and the processes controlling it are important components of the global climate system. Recent research has shown methanogenesis in subglacial sediments. However, the net contribution from subglacial systems to the global methane budget is poorly understood due to a dearth of empirical data. Using measurements via the static chamber method, the flux of methane from recently exposed subglacial sediments at Robertson Glacier, Canadian Rockies was quantified. Methane concentrations were measured from surface gas flux chambers in transects both parallel and perpendicular to the glacier terminus. Over 300 measurements were made during the 2012 melt season (July to September) and used to determine both spatial and temporal variability in the gas fluxes. The chamber farthest from the glacier terminus, approximately 50 m down valley, had an average flux close to zero whereas the chambers nearest the terminus had the highest average fluxes. The average methane efflux from the sediment surface to atmosphere was 0.22 micromoles m -2 d -1. The highest methane efflux during the season, 11.0 micromoles m -2 d -1, was measured in close proximity to the glacier terminus. Shallow sediment cores were collected adjacent to the static chambers and vertical gas concentration profiles were measured from the cores. Within the profiles, methane concentrations were greater than atmospheric concentrations at all depths. Additionally, CO 2, CO and H 2 gas concentrations were analyzed in the cores to evaluate potential microbial metabolic pathways of methane production. Previous studies on methane fluxes from glacial sediments in Greenland and the Swiss Alps used single time point flux measurements during a melt season from multiple locations. This study concludes that such point measurements are unlikely representative for determining a net seasonal flux as they do not consider temporal variability. There was a two order of magnitude ... Thesis glacier glacier* Greenland Montana State University (MSU): ScholarWorks Canada Greenland Robertson Glacier ENVELOPE(165.383,165.383,-71.050,-71.050) |
institution |
Open Polar |
collection |
Montana State University (MSU): ScholarWorks |
op_collection_id |
ftmontanastateu |
language |
English |
topic |
Methane Glaciers Microbiology |
spellingShingle |
Methane Glaciers Microbiology Spotts, Terra Marie Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
topic_facet |
Methane Glaciers Microbiology |
description |
Methane is over 20 times more effective than CO 2 as a greenhouse gas. Thus, its atmospheric concentration and the processes controlling it are important components of the global climate system. Recent research has shown methanogenesis in subglacial sediments. However, the net contribution from subglacial systems to the global methane budget is poorly understood due to a dearth of empirical data. Using measurements via the static chamber method, the flux of methane from recently exposed subglacial sediments at Robertson Glacier, Canadian Rockies was quantified. Methane concentrations were measured from surface gas flux chambers in transects both parallel and perpendicular to the glacier terminus. Over 300 measurements were made during the 2012 melt season (July to September) and used to determine both spatial and temporal variability in the gas fluxes. The chamber farthest from the glacier terminus, approximately 50 m down valley, had an average flux close to zero whereas the chambers nearest the terminus had the highest average fluxes. The average methane efflux from the sediment surface to atmosphere was 0.22 micromoles m -2 d -1. The highest methane efflux during the season, 11.0 micromoles m -2 d -1, was measured in close proximity to the glacier terminus. Shallow sediment cores were collected adjacent to the static chambers and vertical gas concentration profiles were measured from the cores. Within the profiles, methane concentrations were greater than atmospheric concentrations at all depths. Additionally, CO 2, CO and H 2 gas concentrations were analyzed in the cores to evaluate potential microbial metabolic pathways of methane production. Previous studies on methane fluxes from glacial sediments in Greenland and the Swiss Alps used single time point flux measurements during a melt season from multiple locations. This study concludes that such point measurements are unlikely representative for determining a net seasonal flux as they do not consider temporal variability. There was a two order of magnitude ... |
author2 |
Chairperson, Graduate Committee: Mark L. Skidmore |
format |
Thesis |
author |
Spotts, Terra Marie |
author_facet |
Spotts, Terra Marie |
author_sort |
Spotts, Terra Marie |
title |
Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
title_short |
Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
title_full |
Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
title_fullStr |
Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
title_full_unstemmed |
Methane flux from recently exposed subglacial sediments, Robertson Glacier, Canada |
title_sort |
methane flux from recently exposed subglacial sediments, robertson glacier, canada |
publisher |
Montana State University - Bozeman, College of Letters & Science |
publishDate |
2014 |
url |
https://scholarworks.montana.edu/xmlui/handle/1/9139 |
op_coverage |
Robertson Glacier (Canada) |
long_lat |
ENVELOPE(165.383,165.383,-71.050,-71.050) |
geographic |
Canada Greenland Robertson Glacier |
geographic_facet |
Canada Greenland Robertson Glacier |
genre |
glacier glacier* Greenland |
genre_facet |
glacier glacier* Greenland |
op_relation |
https://scholarworks.montana.edu/xmlui/handle/1/9139 |
op_rights |
Copyright 2014 by Terra Marie Spotts |
_version_ |
1766009318800359424 |