Bacterial community structure and carbon turnover in permafrost-affected soils of the Lena Delta, northeastern SiberiaThis article is one of a selection of papers in the Special Issue on Polar and Alpine Microbiology.

• Published in: Canadian Journal of Microbiology
• Main Authors: Wagner, Dirk, Kobabe, Svenja, Liebner, Susanne
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2009
• Subjects: Global warming; lena delta; permafrost; Siberia
• Online Access: http://dx.doi.org/10.1139/w08-121; http://www.nrcresearchpress.com/doi/full-xml/10.1139/W08-121; http://www.nrcresearchpress.com/doi/pdf/10.1139/W08-121

Arctic permafrost environments store large amounts of organic carbon. As a result of global warming, intensified permafrost degradation and release of significant quantities of the currently conserved organic matter is predicted for high latitudes. To improve our understanding of the present and future carbon dynamics in climate sensitive permafrost ecosystems, the present study investigates structure and carbon turnover of the bacterial community in a permafrost-affected soil of the Lena Delta (72°22′N, 126°28′E) in northeastern Siberia. 16S rRNA gene clone libraries revealed the presence of all major soil bacterial groups and of the canditate divisions OD1 and OP11. A shift within the bacterial community was observed along the soil profile indicated by the absence of Alphaproteobacteria and Betaproteobacteria and a simultaneous increase in abundance and diversity of fermenting bacteria like Firmicutes and Actinobacteria near the permafrost table. BIOLOG EcoPlates were used to describe the spectrum of utilized carbon sources of the bacterial community in different horizons under in situ temperature conditions in the presence and absence of oxygen. The results revealed distinct qualitative differences in the substrates used and the turnover rates under oxic and anoxic conditions. It can be concluded that constantly negative redox potentials as characteristic for the near permafrost table horizons of the investigated soil did effectively shape the structure of the indigenous bacterial community limiting its phylum-level diversity and carbon turnover capacity.