Methane oxidation in a peatland core

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: 13 CH4 was added at the water table, and excess 13 CO2 appeared in the gas space above the core. At 20 degreesC in otherwise undisturbed conditions, similar to 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 degrees -25 degreesC) and any depth (0-55 cm) of water table. Changing temperature has important effects on the proportion of CH4 oxidized.