title: Microform-related community patterns of methane-cycling microbes in boreal Sphagnum bogs are site specific.
abstract: Vegetation and water table are important regulators of methane emission in peatlands. Microform variation encompasses these factors in small-scale topographic gradients of dry hummocks, intermediate lawns and wet hollows. We examined methane production and oxidization among microforms in four boreal bogs that showed more variation of vegetation within a bog with microform than between the bogs. Potential methane production was low and differed among bogs but not consistently with microform. Methane oxidation followed water table position with microform, showing higher rates closer to surface in lawns and hollows than in hummocks. Methanogen community, analysed by mcrA terminal restriction fragment length polymorphism and dominated by Methanoregulaceae or 'Methanoflorentaceae', varied strongly with bog. The extent of microform-related variation of methanogens depended on the bog. Methanotrophs identified as Methylocystis spp. in pmoA denaturing gradient gel electrophoresis similarly showed effect of bog, and microform patterns were stronger within individual bogs. Our results suggest that methane-cycling microbes in boreal Sphagnum bogs with seemingly uniform environmental conditions may show strong site-dependent variation. The bog-intrinsic factor may be related to carbon availability but contrary to expectations appears to be unrelated to current surface vegetation, calling attention to the origin of carbon substrates for microbes in bogs.
authors.affiliation: Department of Biosciences, General Microbiology, University of Helsinki, FI-00014, Finland heli.juottonen@alumni.helsinki.fi.
authors.forename: Heli
authors.initials: H
authors.lastname: Juottonen
authors.affiliation: Peatland Ecology Group, Department of Forest Sciences, University of Helsinki, FI-00014, Finland.
authors.forename: Mirkka
authors.initials: M
authors.lastname: Kotiaho
authors.affiliation: Natural Resources Institute Finland, Vantaa Unit, FI-01370 Vantaa, Finland.
authors.forename: Devin
authors.initials: D
authors.lastname: Robinson
authors.affiliation: Natural Resources Institute Finland, Oulu Unit, University of Oulu, FI-90014, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Merilä
authors.affiliation: Natural Resources Institute Finland, Vantaa Unit, FI-01370 Vantaa, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Fritze
authors.affiliation: Peatland Ecology Group, Department of Forest Sciences, University of Helsinki, FI-00014, Finland.
authors.forename: Eeva-Stiina
authors.initials: ES
authors.lastname: Tuittila
mesh_terms: D004262:DNA Restriction Enzymes / Q000235:genetics*; D058645:Denaturing Gradient Gel Electrophoresis; D019605:Euryarchaeota / Q000302:isolation & purification* / Q000378:metabolism; D008697:Methane / Q000378:metabolism*; D042083:Methylocystaceae / Q000302:isolation & purification* / Q000378:metabolism; D010084:Oxidation-Reduction; D012150:Polymorphism, Restriction Fragment Length; D012988:Soil Microbiology; D044003:Sphagnopsida / Q000382:microbiology*; D053833:Wetlands
chemical_list: D004262:DNA Restriction Enzymes; C060629:endodeoxyribonuclease McrA; D008697:Methane
keywords: mcrA; methanogen; methanotroph; microtopography; peatland; pmoA