title: Methane production potentials, pathways, and communities of methanogens in vertical sediment profiles of river Sitka.
abstract: Biological methanogenesis is linked to permanent water logged systems, e.g., rice field soils or lake sediments. In these systems the methanogenic community as well as the pathway of methane formation are well-described. By contrast, the methanogenic potential of river sediments is so far not well-investigated. Therefore, we analyzed (a) the methanogenic potential (incubation experiments), (b) the pathway of methane production (stable carbon isotopes and inhibitor studies), and (c) the methanogenic community composition (terminal restriction length polymorphism of mcrA) in depth profiles of sediment cores of River Sitka, Czech Republic. We found two depth-related distinct maxima for the methanogenic potentials (a) The pathway of methane production was dominated by hydrogenotrophic methanogenesis (b) The methanogenic community composition was similar in all depth layers (c) The main TRFs were representative for Methanosarcina, Methanosaeta, Methanobacterium, and Methanomicrobium species. The isotopic signals of acetate indicated a relative high contribution of chemolithotrophic acetogenesis to the acetate pool.
authors.affiliation: Department of Ecology and Environmental Science, Faculty of Science, Palacky University Olomouc, Czech Republic.
authors.forename: Václav
authors.initials: V
authors.lastname: Mach
authors.affiliation: Department of Ecology and Environmental Science, Faculty of Science, Palacky University Olomouc, Czech Republic.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Blaser
authors.affiliation: Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology Marburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Claus
authors.affiliation: Department of Ecology and Environmental Science, Faculty of Science, Palacky University Olomouc, Czech Republic.
authors.forename: Prem P
authors.initials: PP
authors.lastname: Chaudhary
authors.affiliation: Department of Ecology and Environmental Science, Faculty of Science, Palacky University Olomouc, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Rulík
keywords: T-RFLP; depth profile; isotope fractionation; mcrA; methane production potential; methyl fluoride; river sediment; stable carbon isotope