Kleptsova I.E. 1), Glagolev M.V. 1, 2), Filippov I.V. 2), Maksyutov S.S. 3)
1) Lomonosov Moscow state university
2) Yugra state university, Khanty-Mansiysk
3) National Institute for Environmental Studies, Tsukuba, Japan
The article illustrates experimental measurements of methane fluxes in ridges and ryams providing in summer-autumn period of years 2007-2009 in the middle taiga zone of Western Siberia. Ryams have the lowest CH4 fluxes in this zone (1st quartile/median/3d quartile = 0.00 / 0.02 / 0.14 mgС•m 2•h-1). Ridges have slightly greater methane fluxes (0.01 / 0.13 / 0.36 mgС•m 2•h-1). Areas with local high fluxes reaching the value of approximately 10 mgС•m 2•h-1is also found in both microlandscape types as a result of hydrological and geochemical soil surface heterogeneity. Ryams and ridges have similar emission values owing to floristical and upper peat layer identity. Methane flux zonality in ryams and ridges is revealed. Emission from middle taiga ridges is higher than in north taiga (-0.003 / 0 / 0.04 mgС•m 2•h-1) and lower than in south taiga ridges (0.33 / 0.49 / 0.64 mgС•m 2•h-1); emission from middle taiga ryams is lower than in south taiga ryams (0.05 / 0.56 / 1.55 mgС•m 2•h-1). All data are consolidated in scope of "standard model" Bc7 conception of methane emission. The model contains medians of methane flux distributions on six different microlandscape types depending on their area and duration of methane emission in respective zones. Version Bc7 of this model estimates the value of yearly methane emission in the middle taiga of Western Siberia as 0.69 Mt CH4 per year which means 21.6% of the regional emission. Ryams and ridges in this zone cover over 75% of area accounting for only 4% of regional emission from this territory (0.008 and 0.022 Mt CH4 per year respectively) as a result of adverse conditions for methanogenesis.
Keywords: methane emission, middle taiga, ryams, ridges, Western Siberia.