[ACG38-P08] Intra-seasonal variations in CH4 emissions observed by automatic and manual chambers, and in dissolved CH4 concentration at taiga-tundra boundary in northeastern Siberia
Keywords:methane flux, automatic chambers, dissolved methane, water level, stable isotope ratios, Russian Arctic
To investigate intra-seasonal variation in CH4 emission in detail, we observed CH4 flux by automatic chambers at taiga-tundra boundary in the vicinity of Chokurdakh (70° 37′ N, 147° 55′ E) on the lowland of the Indigirka River in summers from 2013 to 2016. A transect was set across a sedge wet area, a sphagnum wet area and a shrub mound, and automatic chambers were installed at these areas. These chambers were connected to a photoacoustic field gas monitor (INNOVA 1412, LumaSense Technologies) to monitor CH4 flux. To assess variations in CH4 production, oxidation and transport processes, dissolved CH4 concentration, δ13C and δD were observed at observation points of manual chambers in 2011, 2012, 2013 and 2016, and at observation points of both manual and automatic chambers in 2016. Relationship of summer-season variations in CH4 flux against water level changes (precipitation events and drainage) and thawing process of active layer will be discussed in this presentation.