Abstract
In order to investigate the link between the methane dynamics in permafrost deposits and climate changes in the past, we studied the abundance, composition, and methane production of methanogenic communities in Late Pleistocene and Holocene sediments of the Siberian Arctic. We detected intervals of increased methane concentrations in Late Pleistocene and Holocene deposits along a 42ka old permafrost sequence from Kurungnakh Island in the Lena Delta (northeast Siberia). Increased amounts of archaeal life markers (intact phospholipid ethers) and a high variety in genetic fingerprints detected by 16S ribosomal ribonucleic acid gene analyses of methanogenic archaea suggest presently living and presumably active methanogenic archaea in distinct layers predominantly in Holocene deposits, but also in deep frozen ground at 17m depth. Potential methanogenic activity was confirmed by incubation experiments. By comparing methane concentrations, microbial incubation experiments, gene analysis of methanogens, and microbial life markers (intact phospholipid esters and ethers) to already partly degraded membrane lipids, such as archaeol and isoprenoid glycerol dialkyl glycerol tetraethers, we demonstrated that archaeol likely represents a signal of past methanogenic archaea.
Original language | English |
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Pages (from-to) | 305-317 |
Number of pages | 13 |
Journal | Global Biogeochemical Cycles |
Volume | 27 |
Issue number | 2 |
DOIs | |
Publication status | Published - Jun 2013 |
Keywords
- methane
- methanogenic archaea
- lipid biomarker
- climate change
- permafrost
- IONIZATION-MASS-SPECTROMETRY
- LENA DELTA
- ORGANIC-MATTER
- LAPTEV SEA
- COMMUNITY COMPOSITION
- PERMAFROST DEPOSITS
- MARINE-SEDIMENTS
- MEMBRANE-LIPIDS
- THERMAL STATE
- SEQUENCE DATA