title: Methane dynamics in an alpine fen: a field-based study on methanogenic and methanotrophic microbial communities.
abstract: Wetlands are important sources of the greenhouse gas methane (CH4). We provide an in situ study of CH4 dynamics in the permanently submerged soil of a Swiss alpine fen. Physico-chemical pore water analyses were combined with structural and microbiological analyses of soil cores at high vertical resolution down to 50 cm depth. Methanotrophs and methanogens were active throughout the depth profile, and highest abundance of active methanotrophs and methanogens [6.1 × 10(5) and 1.1 × 10(7) pmoA and mcrA transcripts (g soil)(-1), respectively] was detected in the uppermost 2 cm of the soil. Active methanotrophic communities in the near-surface zone, dominated by viable mosses, varied from the communities in the deeper zones, but further changes with depth were not pronounced. Apart from a distinct active methanogenic community in the uppermost sample, a decrease of acetoclastic Methanosaetaceae with depth was observed in concomitance with decreasing root surface area. Overall, root surface area correlated with mcrA transcript abundance and CH4 pore water concentrations, which peaked (137.1 μM) at 10 to 15 cm depth. Our results suggest that stimulation of methanogenesis by root exudates of vascular plants had a stronger influence on CH4 dynamics than stimulation of CH4 oxidation by O2 input.
authors: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
authors: Alessandro G
authors: AG
authors: Franchini
authors: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
authors: Ruth
authors: R
authors: Henneberger
authors: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland.
authors: Meret
authors: M
authors: Aeppli
authors: Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland josef.zeyer@env.ethz.ch.
authors: Josef
authors: J
authors: Zeyer
mesh_terms: D004262:DNA Restriction Enzymes / Q000096:biosynthesis / Q000235:genetics; D019605:Euryarchaeota / Q000145:classification / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D064307:Microbiota / Q000235:genetics*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000235:genetics; D018517:Plant Roots / Q000382:microbiology; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D014867:Water / Q000032:analysis / Q000737:chemistry; D053833:Wetlands
chemical_list: D012987:Soil; D014867:Water; D010105:Oxygenases; C021555:methane monooxygenase; D004262:DNA Restriction Enzymes; C060629:endodeoxyribonuclease McrA; D008697:Methane
keywords: greenhouse gas emissions; mcrA; pmoA; transcripts; wetlands