A model of the processes leading to methane emission from peatland

We present a one-dimensional physicochemical model of the processes leading to methane emission from peatland. The model simulates short-term responses of the methane-emitting system. Biological transformations (respiration, methanogenesis and oxidation of methane) follow modified Michaelis-Menten kinetics, with reaction potentials based on simplified representations of measured data. Root transport properties are similarly schematised. The model simulates measured responses to temperature, water table and inhibitor deposition (acid rain) quite well. Methane emission occurs overwhelmingly through the plant-introducing root transport into the model system typically converts a net sink into a source. Simulations performed using the model highlight the need for caution when extrapolating apparent activation energies or Q(10) factors based on short-term laboratory-based incubations to larger areas and longer time scales. They suggest that short-term temperature response is proportional to baseline activity and, other things being equal, that increasing total root transport capacity above a very low minimum is likely to result in a net decrease in methane flux. (C) 1998 Elsevier Science Ltd. All rights reserved.