Carbon budget of oligotrophic mire sites in the Southern Taiga of Western Siberia

The results of a long-term (1999-2007) investigation of vegetation productivity and carbon dioxide (CO₂) emission from the surface of an oligotrophic mire in southern taiga in Western Siberia are presented. The studied ecosystems include pine--shrub--sphagnum (PSS) community, a similar community with oppressed (low) tree stand (LPSS), and sedge--sphagnum fen (SSF). Net primary production for PSS, LPSS and SSF are equal to 552, 575, and 561 g m⁻² yr⁻¹. The mean respiration during the snow-free season determined by chamber method is 165.8, 105.6, 112.4 mgCO₂ m⁻² h⁻¹ for PSS, LPSS and SSF, respectively. Field measurements of NPP and CO₂ emission in combination with reference data on methane emission, winter CO₂ and CH₄ emissions and carbon export by river run-off were used to develop an overall carbon budget of the mire ecosystems. At present conditions the studied mire ecosystems are net sinks for atmospheric carbon and accumulate peat. Rates of the actual modern carbon accumulation are equal to 21, 112 and 102 g C m⁻² yr⁻¹ for PSS, LPSS and SSF communities.