Fig. 1.
Methane mixing ratio and δ13C measured in air samples collected at 42 cm above ground level throughout a diel period, 5–6 August 2008.
Fig. 2.
Keeling plots showing the source signature of methane from Lompolojänkkä from spring thaw to autumn freeze in 2009. Also included is the Keeling plot for the sampling in August 2008, showing that the summer source signature did not change between 2008 and 2009. The source signature in each case is the intercept of a geometric mean regression. The uncertainty given is the SE in the intercept from the regression.
Table 1. Comparison of wetland methane source signatures calculated from diel and chamber samples in 2009 and some examples from other studies
[i] Numbers in parentheses denote the number of individual chamber experiments.
Fig. 3.
Methane fluxes, air and soil temperatures (at 7 cm below the surface) observed at Lompolojänkkä during the spring thaw in May 2009. The methane flux is derived on site using the eddy covariance technique. The methane flux increases rapidly between 4 and 5 May.
Fig. 4.
Methane fluxes seen during the freezing of Lompolojänkkä wetland during autumn 2009. The decreasing flux correlates with the decreasing soil temperature (measured at 7 cm below the surface).
