title: Abundance and potential metabolic activity of methanogens in well-aerated forest and grassland soils of an alpine region.
abstract: Although methanogens were recently discovered to occur in aerated soils, alpine regions have not been extensively studied for their presence so far. Here, the abundance of archaea and the methanogenic guilds Methanosarcinales, Methanococcales, Methanobacteriales, Methanomicrobiales and Methanocella spp. was studied at 16 coniferous forest and 14 grassland sites located at the montane and subalpine belts of the Northern Limestone Alps (calcareous) and the Austrian Central Alps (siliceous) using quantitative real-time PCR. Abundance of archaea, methanogens and the methanogenic potentials were significantly higher in grasslands than in forests. Furthermore, methanogenic potentials of calcareous soils were higher due to pH. Methanococcales, Methanomicrobiales and Methanocella spp. were detected in all collected samples, which indicates that they are autochthonous, while Methanobacteriales were absent from 4 out of 16 forest soils. Methanosarcinales were absent from 10 out of 16 forest soils and 2 out of 14 grassland soils. Nevertheless, together with Methanococcales they represented the majority of the 16S rRNA gene copies quantified from the grassland soils. Contrarily, forest soils were clearly dominated by Methanococcales. Our results indicate a higher diversity of methanogens in well-aerated soils than previously believed and that pH mainly influences their abundances and activities.
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25 d, 6020 Innsbruck, Austria Katrin.Hofmann@uibk.ac.at.
authors.forename: Katrin
authors.initials: K
authors.lastname: Hofmann
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25 d, 6020 Innsbruck, Austria.
authors.forename: Nadine
authors.initials: N
authors.lastname: Praeg
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25 d, 6020 Innsbruck, Austria.
authors.forename: Mira
authors.initials: M
authors.lastname: Mutschlechner
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25 d, 6020 Innsbruck, Austria.
authors.forename: Andreas O
authors.initials: AO
authors.lastname: Wagner
authors.affiliation: Institute of Microbiology, University of Innsbruck, Technikerstraße 25 d, 6020 Innsbruck, Austria.
authors.forename: Paul
authors.initials: P
authors.lastname: Illmer
mesh_terms: D065928:Forests; D065948:Grassland; D008697:Methane / Q000378:metabolism*; D017012:Methanobacteriales / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017015:Methanococcales / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017018:Methanomicrobiales / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019640:Methanosarcinales / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012987:Soil; D012988:Soil Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S; D012987:Soil; D008697:Methane
keywords: 16S rRNA gene abundance; methanogenic potential; methanogens; parent rock; quantitative real-time PCR; vegetation