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Methane flux in subalpine wetland and
unsaturated soils in the southern Rocky Mountains
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Kimberly P. Wickland, Robert G. Striegl,
Steven K. Schmidt, and M. Alisa Mast
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| Methane exchange between the atmosphere and subalpine wetland and unsaturated soils was evaluated over a 15-month period during 1995-1996. Four vegetation community types along a moisture gradient (wetland, moist-grassy, moist-mossy, and dry) were included in a 100 m sampling transect situated at 3200 m elevation in Rocky Mountain National Park, Colorado. Methane fluxes and soil temperature were measured during snow-free and snow-covered periods, and soil moisture content was measured during snow-free periods. Tehran of mean measured fluxes through all seasons (a positive value represents CH4 efflux to the atmosphere) were: 0.3 to 29.2 mmol CH4m-2d-1 wetland area; 0.1 to 1.8 mmol CH4m-2d-1 moist-grassy area; -0.04 to 0.7 mmol CH4m-2d-1, moist-mossy area; and -0.6 to 0 mmol CH4m-2d-1, dry area. Methane efflux was significantly correlated with soil temperature (5 cm) at the continuously saturated wetland area during snow-free periods. Consumption of atmospheric methane was significantly correlated with moisture content in the upper 5 cm of soil at the dry area. A model based on the wetland flux-temperature relationship estimated an annual methane emission of 2.53 mol CH4m-2 from the wetland. Estimates of annual methane flux based on field measurements at the other sites were 0.12 mol CH4m-2, moist-grassy area; 0.03 mol CH4m-2, moist-mossy area; and -0.04 mol CH4m-2, dry area. Methane fluxes during snow-covered periods were responsible for 25, 73, 23, and 43% for the annual fluxes at the wetland, moist-grassy, moist-mossy, and dry sites, respectively. | |||||||||||
Global Biogeochemical Cycles (1999)
Vol. 13, No. 1: 101-113
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