Methanogenesis occurs in anaerobic microsites of upland soils, especially when high water content restricts O2 diffusion (Section 10.1). Periodic soil methane production may support growth and long-term survival of methanotrophs. Although addition of methane does not always increase atmospheric methane oxidation capacity of soils (e.g. Benstead and King, 1997), stimulated methanogenesis in a tundra soil did result in increased atmospheric methane oxidation (West and Schmidt, 2002). Some methanotrophic bacteria are able to oxidize atmospheric methane for several months after the onset of starvation, even though this does not meet their full maintenance energy requirement (Knief and Dunfield, 2005). The reducing equivalents needed to support methane oxidation in these cells presumably come from storage compounds such as poly-p-hydroxybutyrate (Dawes and Senior, 1973). Methanotrophic populations can therefore potentially grow and build up storage reserves during periods of soil meth-anogenesis, and then continue to consume atmospheric methane afterwards as partial support of their maintenance requirement.
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