Methane Emission from Siberian Wet Polygonal Tundra on Multiple Spatial Scales: Vertical Flux Measurements by Closed Chambers and Eddy Covariance, Samoylov Island, Lena River Delta

Ecosystem-scale measurements and investigations of the small-scale variability of methane emission were carried out in northern Siberian wet polygonal tundra using the eddy covariance technique during the entire 2006 growing season. Simultaneous closed chamber flux measurements were conducted daily at 15 plots in four differently developed polygon centers and a polygon rim from July–September 2006. Our study site was located in the southern part of the Lena River Delta, characterized by arctic continental climate and comparatively cold, continuous permafrost. Controls on methane emission were identified by applying multi-linear and multi-nonlinear regression models. We found a relatively low growing season average methane flux of 18.7 ± 10.2 mg m-2 d-1 on the ecosystem scale and identified near-surface turbulence, soil temperature, and atmospheric pressure as the main controls on the growing season variation methane emissions. On the micro-site scale, fluxes showed large spatial variability and were best described by soil surface temperature