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Methane flux in subalpine wetland and unsaturated soils in the southern Rocky Mountains
Author(s) -
Wickland Kimberly P.,
Striegl Robert G.,
Schmidt Steven K.,
Mast M. Alisa
Publication year - 1999
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/1998gb900003
Subject(s) - methane , environmental science , transect , wetland , snow , flux (metallurgy) , soil water , hydrology (agriculture) , water content , atmosphere (unit) , subalpine forest , moisture , atmospheric sciences , montane ecology , soil science , chemistry , ecology , geology , geography , geomorphology , geotechnical engineering , organic chemistry , meteorology , biology
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. The range of mean measured fluxes through all seasons (a positive value represents CH 4 efflux to the atmosphere) were: 0.3 to 29.2 mmol CH 4 m −2 d −1 wetland area; 0.1 to 1.8 mmol CH 4 m −2 d −1 , moist‐grassy area; −0.04 to 0.7 mmol CH 4 m −2 d −1 , moist‐mossy area; and −0.6 to 0 mmol CH 4 m −2 d −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 CH 4 m −2 from the wetland. Estimates of annual methane flux based on field measurements at the other sites were 0.12 mol CH 4 m −2 , moist‐grassy area; 0.03 mol CH 4 m −2 , moist‐mossy area; and −0.04 mol CH 4 m −2 , dry area. Methane fluxes during snow‐covered periods were responsible for 25, 73, 23, and 43% of the annual fluxes at the wetland, moist‐grassy, moist‐mossy, and dry sites, respectively.