The biological formation and consumption of methane are carried out by very specialized microorganisms, methanogens and methanotrophs. Thereby, methane production results solely from the activity of members of the kingdom Euryarchaeota, the so-called methanogenic archaea (methanogens). The group of microorganisms capable of consuming methane (methanotrophs), however, is more complex, comprising obligate aerobic members of the phyla Proteobacteria (Bowman 1999), and Verrucomicrobiaea (Dunfield et al. 2007; Pol et al. 2007), as well as anaerobically methane-oxidizing archaea in marine habitats (e.g., Boetius et al. 2000), and bacteria of a yet unknown phylum carrying out methane oxidation in the presence of very high nitrate and methane concentration in freshwater habitats (Raghoebarsing et al. 2006). The dominant methane-consuming microorganisms in permafrost soils are those of the Proteobacteria phylum. Because of the pronounced distribution of methanogenic archaea and methanotrophic Proteobacteria in Arctic permafrost soils (reviewed by Wagner 2008, Fig. 15.3) and their significance for the global methane budget, these two groups are of particular attention in this review.
Was this article helpful?