Methanogenic activity and biomass in Holocene permafrost deposits of the Lena Delta, Siberian Arctic and its implication for the global methane budget

Authors

  • DIRK WAGNER,

    1. Research Department Potsdam, Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A45, 14473 Potsdam, Germany,
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  • ANDREAS GATTINGER,

    1. Chair of Soil Ecology, Technical University of Munich, 85758 Oberschleissheim,
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  • ARNDT EMBACHER,

    1. GSF-National Research Center for Environment and Health, Institute of Soil Ecology, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany,
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  • EVA-MARIA PFEIFFER,

    1. Research Department Potsdam, Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A45, 14473 Potsdam, Germany,
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    • 1Present address: Institute of Soil Science, University Hamburg, Allende-Platz 2, 20146 Hamburg.

  • MICHAEL SCHLOTER,

    1. GSF-National Research Center for Environment and Health, Institute of Soil Ecology, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany,
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  • ANDRÉ LIPSKI

    1. Department of Microbiology, University Osnabrück, 49069 Osnabrück, Germany
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D. Wagner, tel. +49 331 288 2159, fax +49 331 288 2137, e-mail: Dirk.Wagner@awi.de

Abstract

Permafrost environments within the Siberian Arctic are natural sources of the climate relevant trace gas methane. In order to improve our understanding of the present and future carbon dynamics in high latitudes, we studied the methane concentration, the quantity and quality of organic matter, and the activity and biomass of the methanogenic community in permafrost deposits. For these investigations a permafrost core of Holocene age was drilled in the Lena Delta (72°22′N, 126°28′E). The organic carbon of the permafrost sediments varied between 0.6% and 4.9% and was characterized by an increasing humification index with permafrost depth. A high CH4 concentration was found in the upper 4 m of the deposits, which correlates well with the methanogenic activity and archaeal biomass (expressed as PLEL concentration). Even the incubation of core material at −3 and −6°C with and without substrates showed a significant CH4 production (range: 0.04–0.78 nmol CH4 h−1 g−1). The results indicated that the methane in Holocene permafrost deposits of the Lena Delta originated from modern methanogenesis by cold-adapted methanogenic archaea. Microbial generated methane in permafrost sediments is so far an underestimated factor for the future climate development.

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