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The Relative Importance of Methanogenesis in the Decomposition of Organic Matter in Northern PeatlandsUsing an isotope-mass balance approach and assuming the equimolar production of CO2 and CH4 from methanogenesis (e.g., anaerobic decomposition of cellulose), we calculate that the proportion of total CO2 production from methanogenesis varies from 37 to 83% across a variety of northern peatlands. In a relative sense, methanogenesis was a more important pathway for decomposition in bogs (80 +/- 13% of CO2 production) than in fens (64 +/- 5.7% of CO2 production), but because fens contain more labile substrates they may support higher CH4 production overall. The concentration of CO2 produced from methanogenesis (CO2-meth) can be considered equivalent to CH4 concentration before loss due to ebullition, plant-mediated transport, or diffusion. Bogs produced slightly less CO2-meth than fens (2.9 +/- 1.3 and 3.7 +/- 1.4 mmol/L, respectively). Comparing the quantity of CH4 present to CO2-meth, fens lost slightly more CH4 than bogs (89 +/- 2.8% and 82 +/- 5.3%, respectively) likely due to the presence of vascular plant roots. In collapsed permafrost wetlands, bog moats produced half the amount of CO2-meth (0.8 +/- 0.2mmol/L) relative to midbogs (1.6 +/- 0.6 mmol/L) and methanogenesis was less important (42 +/- 6.6% of total CO2 production relative to 55 +/- 8.1%).We hypothesize that the lower methane production potential in collapsed permafrost wetlands occurs because recently thawed organic substrates are being first exposed to the initial phases of anaerobic decomposition following collapse and flooding. Bog moats lost a comparable amount of CH4 as midbogs (63 +/- 7.0% and 64 +/- 9.3%).
Document ID
20150023374
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Corbett, J. Elizabeth
(Florida State Univ. Tallahassee, FL, United States)
Tfaily, Malak M.
(Florida State Univ. Tallahassee, FL, United States)
Burdige, David J.
(Old Dominion Univ. Norfolk, VA, United States)
Glaser, Paul H.
(Minnesota Univ. Minneapolis, MN, United States)
Chanton, Jeffrey P.
(Florida State Univ. Tallahassee, FL, United States)
Date Acquired
December 18, 2015
Publication Date
February 24, 2015
Publication Information
Publication: Journal of Geophysical Research: Biogeosciences
Publisher: Wiley
Volume: 120
Issue: 2
Subject Category
Inorganic, Organic And Physical Chemistry
Geophysics
Report/Patent Number
GSFC-E-DAA-TN21088
Funding Number(s)
CONTRACT_GRANT: NSF-EAR-0628349
CONTRACT_GRANT: NSF-DEB-0841158
CONTRACT_GRANT: NNH06CC03B
Distribution Limits
Public
Copyright
Other
Keywords
methane
substrates
carbon dioxide
permafrost
marshlands
bacteria
wetlands

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