Seasonal and inter-annual variability of carbon dioxide exchange at a boreal peatland in north-east European Russia

Abstract

Although peatlands cover about 10 % of north-east European Russia, few publications report carbon dioxide (CO2) fluxes in the tundra and middle taiga peatlands of this region. In this study the CO2 balance of a boreal peatland in the Komi Republic was determined using the eddy covariance method, for the summer periods (10 June to 10 September) of 2012 and 2013. Monthly totals of net ecosystem exchange (NEE) varied significantly over the two years. The total net CO2 flux from the atmosphere to the peatland was 30 % greater in June 2013 than during the same month in 2012. The difference for July was smaller. In 2012 the total CO2 flux in August was 29 % higher, and in September it was 2.4 times lower, than in 2013. Despite the differences in seasonal dynamics of NEE between 2012 and 2013, the mean monthly indicators of gas exchange in the peatland ecosystem were mostly similar. Maximum values of gross photosynthesis (Pgross) and ecosystem respiration (Reco) were observed in July, which is the period of maximum development of the green biomass of plants. The CO2 fluxes were constrained by the precipitation and temperature regimes. During the drought of 2013, Pgross and Reco were mostly influenced by the incidence of precipitation. The peatland was a CO2 sink during both growing seasons and, in June–September 2012, it sequestered 317.66 g m-2 of CO2, which is 10.5 % more than during the same period in 2013. Our results are broadly comparable with measurements in similar peatland ecosystems across northern Europe and south-east Canada.

Keywords

• co2
• eddy covariance
• nee
• pgross
• reco
• seasonal dynamics
• taiga
• water table
• weather