Wet tundra environments of the Arctic are natural sources of the climate relevant trace gas methane. The underlying biogeochemical processes are not yet well understood. The field investigations were carried out on the island Samoylov (N 72°, E 126°) located in the Lena Delta, Siberia. The study site represented an area of typical polygonal patterned grounds with ice-wedges, which were considered for analyses of methane fluxes, organic matter quality and microbial communities.The mean flux rate of the depression was 53.2 ± 8.7 mg CH4 m-2 d-1, whereas the mean flux rate of the dryer rim part of the polygon was 4.7 ± 2.5 CH4 m-2 d-1. The quantity of dissolved organic matter (DOM), which represents an important C pool for microbial communities, correlated significant with the total concentrations of phospholipid fatty acids and ether lipids (PLFA and PLEL) a measure for microbial biomass. Archaeal PLEL concentration (including those for methanogens) was highest between 5-10 cm in the centre and between 20-27 cm in the wall, where humification indices were comparatively low. Although methane oxidation activity was measured, signatures lipids for methanotrophs were not detected, which may be an indication for the presence of hitherto unknown organisms.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL7-From permafrost to deep sea in the Arctic