Studying seasonal variations for methane and carbon dioxide fluxes from wetland ecosystems of the Bakchar bog in Tomsk region

Abstract

Wetland CO2 and CH4 fluxes were observed at the Bakchar bog (N56°51’, E82°51’), West Siberia. Measurements were performed by two solar powered automated systems (Flux-NIES), each consisting of NDIR CO2 analyzer, an SnO2-based methane sensor, six static chambers installed along transects, the air drying and distribution units, and a data-logger. Observations were made during the May to October period in 2014 to 2018 at two types of open wetlands: mesotrophic open bog (E-site) and patterned wetland with forested ridges, flat hollows and water pool (O-site). Each chamber is automatically opened and closed with pneumatic actuator. Water level is measured in the wetland and surrounding forest locations. On the basis of the conducted research, the daily dynamics for CO2 and CH4 fluxes was revealed. Correlation analysis made it possible to describe the dependences for CO2 and CH4 fluxes on the local hydrometeorological conditions of the surface. For example, the high flood of bog’s waters had a decreasing effect on the methane genesis during the period of observation and seasonal variation of the CH4 emissions correlates well with the soil temperature at peat bed depth. Wetland CO2 and CH4 fluxes correlate spatially: higher net uptake CO2 and CH4 emissions are observed at wet mesotrophic locations with higher photosynthesis/respiration rates; lower net uptake CO2 and CH4 emissions were observed on oligotrophic patterned wetland. Another objective for investigation was the integration of carbon fluxes from aquatic systems into terrestrial ones, in order to quantify and better understand the catchment scale carbon budget.