TY - JOUR
T1 - Variations in free-phase gases in peat landforms determined by ground-penetrating radar
AU - Parsekian, Andrew D.
AU - Slater, Lee
AU - Comas, Xavier
AU - Glaser, Paul H.
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2010/4
Y1 - 2010/4
N2 - The spatial variability of biogenic gas produced by methanogenic archaea is difficult to assess within saturated peat soils and is often poorly quantified. This study uses ground-penetrating radar to noninvasively estimate the vertical distribution of biogenic free-phase gas (FPG) in two distinct peat landform types in the Glacial Lake Agassiz Peatland, Minnesota: a near-crest bog and a midslope lawn (i.e., both as defined by surface vegetation communities). Ground-penetrating radar velocities retrieved from common midpoint surveys were modeled using the Complex Refractive Index Model to estimate free-phase gas volumes along one-dimensional vertical profiles. Near-crest bog landforms are characterized by vertical variability in gas content with accumulations along the peat column up to 24% by volume of FPG localized within the deep peat (e.g., 2-4 m depth). Midslope lawn sites show lower total volumes (up to 12% free-phase gas) and less variability that result in a more even free-phase gas distribution throughout the vertical profile. High-resolution data also suggests the presence of thinner layers (<1 m) containing up to 40% free-phase gas at a near-crest site. Our results suggest that spatial distribution of free-phase gas along the peat column may vary in the Glacial Lake Agassiz Peatlands depending on peat landform. Statistical analysis supports vertical variability of ground-penetrating radar velocity data with a 95% confidence limit. Our results could potentially be upscaled using surface vegetation communities to estimate landscape-scale gas storage potential in peat landforms.
AB - The spatial variability of biogenic gas produced by methanogenic archaea is difficult to assess within saturated peat soils and is often poorly quantified. This study uses ground-penetrating radar to noninvasively estimate the vertical distribution of biogenic free-phase gas (FPG) in two distinct peat landform types in the Glacial Lake Agassiz Peatland, Minnesota: a near-crest bog and a midslope lawn (i.e., both as defined by surface vegetation communities). Ground-penetrating radar velocities retrieved from common midpoint surveys were modeled using the Complex Refractive Index Model to estimate free-phase gas volumes along one-dimensional vertical profiles. Near-crest bog landforms are characterized by vertical variability in gas content with accumulations along the peat column up to 24% by volume of FPG localized within the deep peat (e.g., 2-4 m depth). Midslope lawn sites show lower total volumes (up to 12% free-phase gas) and less variability that result in a more even free-phase gas distribution throughout the vertical profile. High-resolution data also suggests the presence of thinner layers (<1 m) containing up to 40% free-phase gas at a near-crest site. Our results suggest that spatial distribution of free-phase gas along the peat column may vary in the Glacial Lake Agassiz Peatlands depending on peat landform. Statistical analysis supports vertical variability of ground-penetrating radar velocity data with a 95% confidence limit. Our results could potentially be upscaled using surface vegetation communities to estimate landscape-scale gas storage potential in peat landforms.
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U2 - 10.1029/2009JG001086
DO - 10.1029/2009JG001086
M3 - Article
AN - SCOPUS:77951038603
SN - 0148-0227
VL - 115
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 2
M1 - G02002
ER -