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Winter methane dynamics in a temperate peatland
Author(s) -
Melloh Rae A.,
Crill Patrick M.
Publication year - 1996
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 - 10.1029/96gb00365
Subject(s) - peat , snow , environmental science , atmospheric sciences , temperate climate , atmosphere (unit) , flux (metallurgy) , hydrology (agriculture) , climatology , geology , chemistry , meteorology , geomorphology , geography , ecology , geotechnical engineering , organic chemistry , biology , archaeology
Methane (CH 4 ) dynamics in pore water, snow pore air, and surface emissions were investigated in a temperate poor fen in New Hampshire over several winters. Total snowfall and average air temperatures during winter months (defined as December, January, and February) were climatologic indicators of significant flux rates from this midlatitude poor fen. Average winter emissions, for the five winters ending in 1994–1995, were 20, 39, 53, 56, and 26 mg m −2 d −1 , amounting to 2.0, 5.2, 6.6, 9.2, and 2.0% of the total annual fluxes, respectively. Totaling emissions over 5 years that represent low to average snowfall, winter accounted for 4.3% of emissions to the atmosphere. Winter flux rates were near 55 mg m −2 d −1 for years with average snowfall, and 25 mg m −2 d −1 for years with low snowfall. Concentrations of CH 4 sampled in pore water immediately beneath the ice were highly variable (0 to 1.1 mM). The concentration magnitude and standard deviation increased toward the fen center and correlated with spatial variation in hydrology, peat texture, and peat depth. CH 4 stores increased in the near‐surface pore water as the ice cover formed. Seasonal CH 4 buildup in deeper peat began near the end of the growing season, probably due to changing transport mechanisms and temperature effects on solubility. Stored CH 4 in the 25‐ to 75‐cm peat layer decreased by 2.7 g m −2 between January and June 1995.