Methane oxidation in a peatland core

Publisher Website
Google Scholar
Abstract
We made an experiment on a 30 cm diameter core of Sphagnum‐dominated vegetation and peat to estimate the parameters controlling methane oxidation during movement to the ambient air: 13CH4 was added at the water table, and excess 13CO2 appeared in the gas space above the core. At 20°C in otherwise undisturbed conditions, ∼22% of CH4 was oxidized to CO2 during passage up through the overlying 10‐cm thick unsaturated peat and plants. We simulated the experiment, with seven parameters: transfer coefficients in water, in the gas phase, and through the container wall; the rate of CH4 and of CO2 generation; and the two parameters of a hyperbolic relation between CH4 concentration and the rate of CH4 oxidation. We optimized these parameters to fit the experimental results, and then were able to generalize to any temperature (0°−25°C) and any depth (0‐55 cm) of water table. Changing temperature has important effects on the proportion of CH4 oxidized.