Carbon Dioxide and Methane Distribution in Peat Deposits of an Oligotrophic Forest Swamp in Western Siberia and Their Emission

Abstract

Swamps and wetlands of forested areas, as well as the non-forest swamps are jointly involved in the global carbon cycle. They play an important role in depositing the greenhouse gases. This article analyses the long-term dynamics of the greenhouse gases (CO2 and CH4) concentration in a peat deposit and their emission in a natural and reclaimed oligotrophic bog in the southern taiga zone of Western Siberia. It was found that a significant role in the CO2 and CH4 concentration dynamics in the peat deposits belongs to the weather conditions of each month of the warm period, the botanical composition and the activity of biochemical processes, as well as the structure and physical and mechanical properties of a peat deposit. Also identified were the intra-deposit, spatial and temporal dynamics of the greenhouse gases concentrations’ indicators. It has been proven that there are multicomponent dependences of CO2 and CH4 concentrations on the parameters of external and intra-deposit conditions. The concentrations’ parameters in the oligotrophic bog’s peat deposit from the swampy catch basin of the Klyuch river were determined as follows: extreme concentrations of CO2 were 0.002–3.64 mmol/dm3, extreme concentrations of CH4 were 0.003–2.03 mmol/dm3; the CO2 normalised fluxes varied from /–22.2/ to 157.8 mg C/(m2 · h), the CH4 normalised fluxes’ extreme values were equal /–3.0/–5.3 mg C/(m2 · h), the CO2 fluxes for the warm period were 20–110 g C/(m2 · year), the CH4 fluxes for the warm period were 0.8–3.7 C/(m2 · year). At the forest reclamation site, a slight increase in the CO2 normalised fluxes activity was revealed compared to a natural swamp, while the greenhouse gases’ concentrations in the peat deposit were found to be comparable in both cases. It was shown that in the absence of an operating drainage system, the process of re-bogging occurs. Due to the vast areas of the West Siberian Plain’s swamps and the aggressive nature of the bogging process, moderate and selective forest reclamation is suggested for its taiga zone.