This work was integrated into the Russian-German joint venture project System Laptev Sea 2000. The focus of this project was to extent our knowledge about the Laptev Sea system in north-east Siberia obtained through previous Russian-German projects, such as the Laptev Sea System (1994-1997), and Taymyr (1994-1997). Studies on Quaternary environmental changes, Arctic coastal dynamics and recent periglacial processes including ecological studies on permafrost soils and ecosystems of the central Lena Delta were in the focus of the recent project (Schirrmeister et al., 2004). The present work contributes to the last aspect by investigating the field of methane fluxes in polygonal tundra environments of the Lena Delta. Field work and sampling of this study was conducted during the expeditions LENA 2002 and LENA 2005 (Samoylov Island, Lena Delta, Siberia) with a personal participation in the last expedition. The work was performed in the frame of the International Max Planck Research School for Marine Microbiology (MarMic) mainly at the Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam. Some analyses were conducted at the Max Planck Institute for Marine Microbiology in Bremen. This study is presented in English as a cumulative Ph.D. thesis at the University of Bremen (Fachbereich 02). The thesis consists of a general introduction to the particular research field including the scientific background as well as aims and objectives of this study. The study area is described in an extra chapter. The main part of this thesis consists of three manuscripts with first authorship and a final synthesis representing the conclusions as well as critical remarks and future prospects of this work.