The Relative Importance of Methanogenesis in the Decomposition of Organic Matter in Northern Peatlands

Authors

J. Elizabeth Corbett
Malak M. Tfaily
David J. Burdige, Old Dominion UniversityFollow
Paul H. Glaser
Jeffrey P. Chanton

Document Type

Article

Publication Date

2015

DOI

10.1002/2014jg002797

Publication Title

Journal of Geophysical Research: Biogeosciences

Volume

120

Issue

2

Pages

280-293

Abstract

Using 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 (CO_2-meth) can be considered equivalent to CH₄ concentration before loss due to ebullition, plant-mediated transport, or diffusion. Bogs produced slightly less CO_2-meth than fens (2.9 ±1.3 and 3.7 ±1.4mmol/L, respectively). Comparing the quantity of CH₄ present to CO_2-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 CO_2-meth (0.8 ± 0.2mmol/L) relative to midbogs (1.6 ± 0.6mmol/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%).

Original Publication Citation

Corbett, J.E., Tfaily, M.M., Burdige, D.J., Glaser, P.H., & Chanton, J.P. (2015). The relative importance of methanogenesis in the decomposition of organic matter in northern peatlands. Journal of Geophysical Research-Biogeosciences, 120(2), 280-293. doi: 10.1002/2014jg002797

Repository Citation

Corbett, J. Elizabeth; Tfaily, Malak M.; Burdige, David J.; Glaser, Paul H.; and Chanton, Jeffrey P., "The Relative Importance of Methanogenesis in the Decomposition of Organic Matter in Northern Peatlands" (2015). OES Faculty Publications. 78.
https://digitalcommons.odu.edu/oeas_fac_pubs/78