Knoblauch, C.

Koch, Kristina

Wagner, Dirk

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Diversity of Archaea in submarine permafrost sedimentsof the Laptev Sea, Siberian ArcticK. Koch1, C. Knoblauch2, D. Wagner1January 16, 20071 Alfred Wegener Institute for Polar and Marine Research, Research Department Potsdam,Telegrafenberg A43, 14473 Potsdam, Germany, 2 Institute of Soil Science, University ofHamburg, Allende-Platz 2, 20146 Hamburg, Germanykkoch@awi-potsdam.deAtmospheric methane is the second most important greenhouse gas after carbon dioxide.Carbon-rich permafrost sediments are an important source of methane. Due to the Holocenerise of the artic sea level, large areas of formerly coastal permafrost were buried under the sea,creating a submarine permafrost. In order to better understand the methane cycle in submarinepermafrost, geochemical and molecular ecological studies on archaeal diversity have been carriedout which particularly examine the role of methanogens. In this study frozen sediments wereextracted from a 77 meter deep core in the Laptev Sea shelf, North Eastern Siberia, which havebeen dated to approximately 111,000 years BP.In these sediments the total organic carbon (TOC) content varied between 0.03 and 8.70 %with highest values between 53m - 62m depth below the sea ﬂoor. Methane concentrations variedalong the core between 0 - 284 nmol CH4 g−1. Highest values were found in the layer with thehighest amount of TOC. Extremely low δ 13 CH4 values (-75h) indicated active methanogenesisin this zone.A nested polymerase chain reaction (PCR) ampliﬁcation for denaturing gradient gel elec-trophoresis (DGGE) was applied to the samples with low and high amount of methane in orderto analyze the archaeal diversity in submarine permafrost sediments based on 16S rDNA. Forthe nested PCR, the archaeal primers Ar4F-Ar958R were used, followed by GC_PARCH340F-Ar958R, GC_357F-0619R and GC_340F-519R as second primer combinations. DNA fragmentsfrom DGGE gels were sequenced and phylogenetically analysed.Further clone library analyses are planned for a detailed study on the microbial communitycomposition and their function in the submarine ecosystem.1

Diversity of Archaea in submarine permafrost sediments of the Laptev Sea, Siberian Arctic

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