Xavier Comas and Lee Slater

1. Comas, X., Slater. L. and Reeve, A., 2005, Spatial variability in biogenic gas accumulations in peat soils is revealed by ground penetrating radar (GPR), Geophysical Research Letters, 32, L08401, doi:10.1029/2004GL022297

We have pioneered the development of GPR as a method for non-invasively investigating biogenic gas dynamics and carbon cycling within peatlands. Paper #1 is the first demonstration that GPR can be used to determine the distribution of biogenic gas in a peatland and offers evidence to support conceptual models for methane accumulation within peatlands.


2. Comas, X. and Slater, L., 2007, Evolution of biogenic gasses in peat blocks inferred from noninvasive dielectric permittivity measurements, Water Resources Research, 43, W05424, doi:10.1029/2006WR005562

Paper #2 describes laboratory GPR measurements on peat blocks during biogenic methane production, transport and release to the atmosphere, demonstrating under controlled conditions how the technique could be used to monitor biogenic gas dynamics in peatlands.


3. Comas, X., Slater, L. and Reeve, A., 2007, In situ monitoring of free-phase gas accumulation and release in peatlands using ground penetrating radar (GPR), Geophysical Research Letters, 34, L06402, doi:10.1029/2006GL029014

Paper #3 is the first to demonstrate this concept of monitoring free phase gas dynamics in the field and provides new evidence for controls of atmospheric pressure in regulating rapid outgassing (ebullition) from peatlands.


4. Comas, X., Slater, L. and Reeve, A., 2008, Seasonal geophysical monitoring of biogenic gasses in a northern peatland: implications for temporal and spatial variability in free phase gas production rates, Journal of Geophysical Research-Biogeosciences, 113, G01012, doi:10.1029/2007JG000575

Paper #4 uses the same approach to investigate differences in free phase gas dynamics during winter and summer, and describes a striking build up of free phase gas in peatlands during winter months when the frozen surface prevents gas release.


5. Comas, X., Slater, L., and Reeve, A. 2011. Atmospheric Pressure Drives Changes in the Vertical Distribution of Biogenic Free-Phase Gasses in a Northern Peatland. Journal of Geophysical Research-Biogeosciences, 116, G04014, doi:10.1029/2011JG001701.

Paper #5 further examines the role of atmospheric pressure in controlling the vertical distribution of biogenic gases in peat soils using time-lapse GPR measurements at the field scale, and suggests how soil properties may regulate gas releasing events in peatlands.


6. Parsekian, A. D., X. Comas, L. Slater, and P. H. Glaser, 2011, Geophysical evidence for the lateral distribution of free phase gas at the peat basin scale in a large northern peatland, Journal of Geophysical Research,116, G03008, doi:10.1029/2010JG001543.

Paper #6 shows how GPR can be used to determine the distribution of free-phase gas across a peatland and the changes in gas content and distribution with vegetation type.


7. Parsekian*, A., Slater, L. and Gimenez, D., 2012, Application of ground penetrating radar to measure near-saturation soil water content in peat soils, Water Resources Research, W02533, 9 PP. doi:10.1029/2011WR011303

Paper #7 critically examines validity of the Complex Refractive Index Model (CRIM) for predicting free phase gas content in peat soils and develops empirical relations for quantifying free phase gas content from GPR measurements under conditions simulating the processes that change free phase gas content in the field.