Characterization of peat structure using X-ray computed tomography and its control on the ebullition of biogenic gas bubbles
Article first published online: 9 MAR 2011
Copyright 2011 by the American Geophysical Union.
Journal of Geophysical Research: Biogeosciences (2005–2012)
Volume 116, Issue G1, March 2011
How to Cite
2011), Characterization of peat structure using X-ray computed tomography and its control on the ebullition of biogenic gas bubbles, J. Geophys. Res., 116, G01024, doi:10.1029/2010JG001478., and (
- Issue published online: 9 MAR 2011
- Article first published online: 9 MAR 2011
- Manuscript Accepted: 7 DEC 2010
- Manuscript Revised: 1 DEC 2010
- Manuscript Received: 10 JUL 2010
- X-ray CT;
- peatland development;
- peat properties
 The structural arrangement of peat constituents controls the hydrological and thermal properties of peat. However, the importance of these structural characteristics on other physical processes within a peatland has not been fully assessed. Here, we evaluate the importance of peat structure on its ability to entrain biogenic gas bubbles and control ebullition, an important transport mechanism for methane. X-ray computed tomography (CT) was applied to characterize the structure of a range of peats at varying levels of decomposition. The structural properties of the peat were quantified from a vector representation of the CT images, and the potential of each sample to entrain biogenic gas bubbles was quantified using a rule-based Monte Carlo model that calculates the tortuosity of bubbles pathways through the peat. Sixty-six percent of the variability in the trapping potential of the peat results from porosity variations and 34% from structural variations between samples. A metric that represents this structural control was not identified for all peat types because of difficulties adequately representing some peats as a vector network. However, for S. magellanicum peat we were able to establish that the influence of peat structure on the entrainment of gas bubbles is characterized by v, the average vector length of the stems and branches. Peat characterized by longer structural components (larger v) enhances the entrainment of gas bubbles. Our findings demonstrate the need to incorporate some representation of the peat structure in numerical models of biogenic gas transport in peat.