Methane fluxes from the transitional swamp in the middle taiga zone of the Komi Republic: results of three-year observations

The annual methane fluxes from eutrophic floodplain swamp were studied. The sampling spot is located in the basin of the Sysola River (Komi Republic) in the middle taiga zone (61˚33'25.0˝ N, 50˚46'28˝ E). The vascular plant flora of the examined swamp is represented by Carex aquatilis, C. vesicaria, Eriophorum polystachion, E. vaginatum, Menyanthes trifoliata, Comarum palustre, Equisetum fluviatile, Oxycoccus quadripetalus, Andromeda polifolia, Alnus incana, Betula pubescens, Pinus sylvestris. Moss cover is formed by different species from Sphagnum genus with Sphagnum girgensohnii as the dominant one. The year- round measurements of the methane emissions were carried out in 2011-2014 by “closed dark chambers” method. We measured the main climatic parameters and environmental factors which affect methane emissions (air and peat temperature at different depths, the level of swamp waters). Methane dynamics in the swamp water was studied. The annual methane emission from the floodplain swampduring research period was in the range of 15.8 - 36.9 g CH4 m-2. During vegetation period, methane fluxes ranged from 14.4 to 30.5 g CH4 m-2, in winter - from 1.4 to 6.4 g CH4 m-2. The maximum seasonal fluxes of methane were observed during growing season of 2013. That was the period with the highest average daily temperatures. Methane emission during winter was from 8.8 to 19.3% from the annual fluxes. For the studied swamp, we obtained the simplest prediction model which is based on temperature in a 30 cm peat horizon as a predictor. It allows to model fluxes with high sufficiency and accuracy for both summer and winter seasons. In future, the obtained data can be used to estimate regional flows of methane from the transitional floodplain swamps in the European Northeast.