Methane fluxes from a northern peatland : mechanisms controlling diurnal and seasonal variation and the magnitude of aerobic methanogenesis

Abstract

Continuous eddy covariance measurements were conducted for a 125 day period, throughout the 2007 growing season, in a northern Alberta peatland. Significant diurnal and seasonal variation in methane fluxes were observed. Diurnal variation in methane flux was suggested to be due to variation in soil temperature and methane convective flow through vegetation to the atmosphere. Seasonal variation in methane flux was associated with a variety of factors, most notably seasonal variation in the capacity for methane emission at 10 ºC (R10). The R10 values varied as a function of soil temperature and were an important control of seasonal variation in methane flux. Also, a greenhouse gas budget was calculated comparing net methane emission and net CO2 sequestration. This analysis indicated that the peatland was acting as a net sink of radiative forcing agents for the 2007 growing season.