Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland
Methane flux from high latitude wetlands is both a critical component of the global CH4 budget, and highly sensitive to global climate change, with expected increases in emissions as permafrost thaws. Gaps in our understanding of the mechanisms driving changing CH4 production and consumption dynamic...
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2011
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ftuninhampshire:oai:scholars.unh.edu:earthsci_facpub-1411 2023-05-15T15:14:51+02:00 Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland McCalley, C K Wehr, R A Crill, P Chanton, J Hodgkins, S B Nelson, D D McManus, J B Zahniser, M Rich, V Tyson, G W Monday, R Frolking, Steve Li, Changsheng Saleska, S R 2011-12-01T08:00:00Z https://scholars.unh.edu/earthsci_facpub/412 http://abstractsearch.agu.org/meetings/2011/FM/B12C-03.html unknown University of New Hampshire Scholars' Repository https://scholars.unh.edu/earthsci_facpub/412 http://abstractsearch.agu.org/meetings/2011/FM/B12C-03.html Earth Sciences Scholarship text 2011 ftuninhampshire 2023-01-30T21:35:11Z Methane flux from high latitude wetlands is both a critical component of the global CH4 budget, and highly sensitive to global climate change, with expected increases in emissions as permafrost thaws. Gaps in our understanding of the mechanisms driving changing CH4 production and consumption dynamics under permafrost thaw, however, limit our ability to predict the magnitude of this response under future climate conditions. To address these gaps, we quantified the isotopic composition of carbon gas fluxes (δ13C of CH4 and CO2) from a high latitude (68° N) wetland in Sweden (Stordalen Mire) to partition net CH4 emissions into its component parts, methanogenesis (including both acetoclastic, and CO2-reductive pathways) and methanotrophy (which consumes CH4 primarily via aerobic metabolism). We used newly developed quantum cascade laser technology, linked to automated chambers, to quantify isotopes at high frequency. Our measurements across a permafrost thaw gradient, going from permafrost-dominated, well-drained palsas to intermediate permafrost sites dominated by Sphagnum spp. to wet sites with no underlying permafrost, dominated by Eriophorum angustifolium, show both large increases in productivity and CH4 emissions as well as shifts in the CH4 production pathway. Across this permafrost thaw gradient the isotopic composition of CH4 becomes 13C enriched, due to increased acetoclastic CH4 production. While the palsa sites have no detectable CH4 emissions, fluxes in the Sphagnum site have an average isotopic composition of -79‰, a value indicative of CH4 production dominated by CO2 reduction, in contrast the isotopic composition of CH4 produced in the Eriophorum sites ranged from -71 to -57‰, showing increased CH4 production via the acetate pathway. We also observed an increase in acetoclastic methanogenesis as the growing season progressed. Together, these initial results suggest that thaw induced changes in hydrology and plant community composition increase peat lability, stimulating acetate fermentation and ... Text Arctic Climate change Eriophorum palsa palsas permafrost University of New Hampshire: Scholars Repository Arctic Stordalen ENVELOPE(7.337,7.337,62.510,62.510) |
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Open Polar |
collection |
University of New Hampshire: Scholars Repository |
op_collection_id |
ftuninhampshire |
language |
unknown |
description |
Methane flux from high latitude wetlands is both a critical component of the global CH4 budget, and highly sensitive to global climate change, with expected increases in emissions as permafrost thaws. Gaps in our understanding of the mechanisms driving changing CH4 production and consumption dynamics under permafrost thaw, however, limit our ability to predict the magnitude of this response under future climate conditions. To address these gaps, we quantified the isotopic composition of carbon gas fluxes (δ13C of CH4 and CO2) from a high latitude (68° N) wetland in Sweden (Stordalen Mire) to partition net CH4 emissions into its component parts, methanogenesis (including both acetoclastic, and CO2-reductive pathways) and methanotrophy (which consumes CH4 primarily via aerobic metabolism). We used newly developed quantum cascade laser technology, linked to automated chambers, to quantify isotopes at high frequency. Our measurements across a permafrost thaw gradient, going from permafrost-dominated, well-drained palsas to intermediate permafrost sites dominated by Sphagnum spp. to wet sites with no underlying permafrost, dominated by Eriophorum angustifolium, show both large increases in productivity and CH4 emissions as well as shifts in the CH4 production pathway. Across this permafrost thaw gradient the isotopic composition of CH4 becomes 13C enriched, due to increased acetoclastic CH4 production. While the palsa sites have no detectable CH4 emissions, fluxes in the Sphagnum site have an average isotopic composition of -79‰, a value indicative of CH4 production dominated by CO2 reduction, in contrast the isotopic composition of CH4 produced in the Eriophorum sites ranged from -71 to -57‰, showing increased CH4 production via the acetate pathway. We also observed an increase in acetoclastic methanogenesis as the growing season progressed. Together, these initial results suggest that thaw induced changes in hydrology and plant community composition increase peat lability, stimulating acetate fermentation and ... |
format |
Text |
author |
McCalley, C K Wehr, R A Crill, P Chanton, J Hodgkins, S B Nelson, D D McManus, J B Zahniser, M Rich, V Tyson, G W Monday, R Frolking, Steve Li, Changsheng Saleska, S R |
spellingShingle |
McCalley, C K Wehr, R A Crill, P Chanton, J Hodgkins, S B Nelson, D D McManus, J B Zahniser, M Rich, V Tyson, G W Monday, R Frolking, Steve Li, Changsheng Saleska, S R Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
author_facet |
McCalley, C K Wehr, R A Crill, P Chanton, J Hodgkins, S B Nelson, D D McManus, J B Zahniser, M Rich, V Tyson, G W Monday, R Frolking, Steve Li, Changsheng Saleska, S R |
author_sort |
McCalley, C K |
title |
Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
title_short |
Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
title_full |
Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
title_fullStr |
Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
title_full_unstemmed |
Novel stable isotope laser spectrometry elucidates changing mechanisms of CH4 production and consumption across a climate change sequence in an arctic wetland |
title_sort |
novel stable isotope laser spectrometry elucidates changing mechanisms of ch4 production and consumption across a climate change sequence in an arctic wetland |
publisher |
University of New Hampshire Scholars' Repository |
publishDate |
2011 |
url |
https://scholars.unh.edu/earthsci_facpub/412 http://abstractsearch.agu.org/meetings/2011/FM/B12C-03.html |
long_lat |
ENVELOPE(7.337,7.337,62.510,62.510) |
geographic |
Arctic Stordalen |
geographic_facet |
Arctic Stordalen |
genre |
Arctic Climate change Eriophorum palsa palsas permafrost |
genre_facet |
Arctic Climate change Eriophorum palsa palsas permafrost |
op_source |
Earth Sciences Scholarship |
op_relation |
https://scholars.unh.edu/earthsci_facpub/412 http://abstractsearch.agu.org/meetings/2011/FM/B12C-03.html |
_version_ |
1766345258947313664 |