title: Biogeochemistry of methane and methanogenic archaea in permafrost.
abstract: This study summarizes the findings of our research on the genesis of methane, its content and distribution in permafrost horizons of different age and origin. Supported by reliable data from a broad geographical sweep, these findings confirm the presence of methane in permanently frozen fine-grained sediments. In contrast to the omnipresence of carbon dioxide in permafrost, methane-containing horizons (up to 40.0 mL kg(-1)) alternate with strata free of methane. Discrete methane-containing horizons representing over tens of thousands of years are indicative of the absence of methane diffusion through the frozen layers. Along with the isotopic composition of CH(4) carbon (delta(13)C -64 per thousand to -99 per thousand), this confirms its biological origin and points to in situ formation of this biogenic gas. Using (14)C-labeled substrates, the possibility of methane formation within permafrost was experimentally shown, as confirmed by delta(13)C values. Extremely low values (near -99 per thousand) indicate that the process of CH(4) formation is accompanied by the substantial fractionation of carbon isotopes. For the first time, cultures of methane-forming archaea, Methanosarcina mazei strain JL01 VKM B-2370, Methanobacterium sp. strain M2 VKM B-2371 and Methanobacterium sp. strain MK4 VKM B-2440 from permafrost, were isolated and described.
authors.affiliation: Institute of Physicochemical and Biological Problems in Soil Sciences, Russian Academy of Sciences, Moscow, Russian Federation. rivkina@issp.serpukhov.su
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Rivkina
authors.forename: Viktoria
authors.initials: V
authors.lastname: Shcherbakova
authors.forename: Kestas
authors.initials: K
authors.lastname: Laurinavichius
authors.forename: Lada
authors.initials: L
authors.lastname: Petrovskaya
authors.forename: Kirill
authors.initials: K
authors.lastname: Krivushin
authors.forename: Gleb
authors.initials: G
authors.lastname: Kraev
authors.forename: Svetlana
authors.initials: S
authors.lastname: Pecheritsina
authors.forename: David
authors.initials: D
authors.lastname: Gilichinsky
mesh_terms: D001110:Arctic Regions; D002247:Carbon Isotopes / Q000032:analysis; D003247:Conservation of Natural Resources; D019605:Euryarchaeota / Q000302:isolation & purification* / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D008697:Methane / Q000032:analysis* / Q000378:metabolism; D017014:Methanobacterium / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D008697:Methane