Methane oxidation potential of the arctic wetland soils of a taiga-tundra ecotone in northeastern Siberia

Figures & data

Table 1. Summary of samples used and experimental setup

Year		Bottle incubation experiment			Methane flux with inhibitor
		Soil layer (cm)	Effect of
2012		0–10	Vegetation type Nutrients		-
2013		0–2, 4–6, 8–10	Depth (1)		-
2014		0–10	Temerature		Short exposure time
2015		0–10, 10–20, 30–40(moss), 37–46(sedge)	Depth (2)		Long exposure time

Figure 1. Temporal change of methane concentration in the headspace of the microcosms with soil samples collected from the different vegetation types in 2012 (a, moss; b; sedge; c, moss in the mound) treated with inorganic nutrient and black carbon. Bars indicate the standard error (n = 3)

Table 2. Estimated potential methane oxidation rate of soil samples from the wetlands of northeastern Siberia (average ± std error, n = 3)

Year	Vegetation	Depth (cm)	Oxidation rate (nmol h^−1 gdw^−1)
2013	Moss	0–2	268 ± 34
		4–6	496 ± 87
		8–10	242 ± 27
	Sedge	0–2	181 ± 16
		4–6	126 ± 27
		8–10	117 ± 24
2015	Moss	0–10	256 ± 1
		10–20	321 ± 21
		30–40	54 ± 1
	Sedge	0–10	138 ± 1
		10–20	94 ± 1
		36–47	0

Figure 2. Methane oxidation by the different depth layers of moss- and sedge- dominated soils in 2013 (a and b) and 2015 (c and d). Bars indicate the standard error (n = 3)

Figure 3. Vertical profile of dissolved oxygen in pore water of the wetland soils. Three independent measurements for sedge- and moss-dominated wetlands were done at the study site in 2014

Figure 4. Effect of incubation temperature on methane oxidation by (a) moss and (b) sedge-dominated peat samples and (c) the temperature dependence of the methane oxidation rate (0–10 cm) (2014). Bars indicate the standard error (n = 3). Data marked with different letters are significantly different (P < 0.05, as determined by Tukey’s honestly significant difference test)

Figure 5. Temperature coefficient (Q₁₀) of methane oxidation estimated between different temperature ranges

Figure 6. Effect of CH₂F₂ on methane flux from wetland estimated by the closed chamber method. Methane flux 1, 1st measurement without CH₂F₂; Methane flux 2, 2nd measurement after injection with or without CH₂F_2.