Annual Carbon Gas Emissions from a Boreal Peatland in Continuous Permafrost Zone, Northeast China

Abstract

Peatland is a significant ecosystem that has accumulated one-third of the soil carbon in boreal regions. However, the net carbon balance, particularly with current carbon emissions, remains unclear. In this study, the annual ecosystem respiration and CH 4 fluxes from a peatland located in Northeast China are reported. Ecosystem respiration fluxes from the shrub-moss-and Eriophorum-dominated communities in the peatland varied from 12 to 272 mg C m À2 h À1 during the snow-free season, and the Eriophorumdominated community emitted more CO 2 . Rates of ecosystem respiration were strongly regulated by temperature and water table depth. The CH 4 fluxes emitted from the peatland throughout a year varied with the type of the vegetation community during the snow-free season. No distinct episodic CH 4 efflux during the freeze-thaw cycles was observed from the shrub-moss-dominated community, whereas a subtle pulse of CH 4 was found in the Eriophorum-dominated community. The annual ecosystem respiration and CH 4 fluxes from the peatland were 356 and 1.51 g C m À2 per year, respectively. The contributions of CO 2 and CH 4 fluxes from the snowy season to annual emissions were much lower than those found in other boreal peatlands, whereas 24% of the annual methane flux was emitted during the freeze-thaw cycles. The results highlight the importance of gaseous carbon efflux in the estimation of carbon flux from peatlands, as well as the contribution of carbon efflux during the snow-covered season.

Driving Factors on Greenhouse Gas Emissions in Permafrost Region of Daxing'an Mountains, Northeast China

“…The CH 4 emissions ranged from −0.248 to 11.459 mg m −2 hr −1 and were higher than those reported for Alaska (0.256–7.8 mg m −2 hr −1 ; Myers‐Smith et al., 2007; Wickland et al., 2006), subarctic (−0.02–6.36 mg m −2 hr −1 ; Jammet et al., 2017; Voigt et al., 2017), northeast China (−1.8–4.8 mg m −2 hr −1 ; Liu et al., 2015; Miao et al., 2016; Sun et al., 2018), Tibetan Plateau (−22.6–4.7 mg m −2 hr −1 ; Chen et al., 2017; Yang, Peng, Olefeld, et al., 2018; Yun et al., 2018), Siberia (−0.013–1.024 mg m −2 hr −1 ; Takakai et al., 2008a, 2008b), and Canada (∼0 mg m −2 hr −1 ; Turetsky et al., 2007). Generally, the CH 4 emissions from the Daxing'an Mountains were higher than those of other permafrost regions.…”

“…The ranges of CO 2 emissions from the Daxing'an Mountains were within the range of previous publications. The thermokarst lakes are considered “hot spots” for CO 2 emissions; the average CO 2 emission is 1,876 mg m −2 hr −1 , higher than the peak CO 2 emission from the Daxing'an Mountains (Liu et al., 2015; Miao et al., 2016; Wickland et al., 2006). Permafrost thawing would cause the decomposition of fixed carbon, promoting the release of CO 2 .…”

“…As a consequence, the carbon and nitrogen cycles will be more active, making the Daxing'an Mountains an extremely climate‐sensitive region. Previous studies mainly focused on temporal variation of greenhouse gas emissions in this region (Gao et al., 2019a, 2019b; Miao et al., 2016; Zhang et al., 2015), indicating that the Daxing'an Mountains play an essential role in releasing greenhouse gases from permafrost regions (Gao, Yao, Liang, et al., 2019; Liu et al., 2015; Sun et al., 2018). However, the difference in greenhouse gas emissions and their driving factors among different permafrost ecosystems have not been touched yet.…”

Response of Methane and Nitrous Oxide Emissions from Peatlands to Permafrost Thawing in Xiaoxing’an Mountains, Northeast China

“…Jin et al [41] predicted that permafrost areas would decline to an estimated 35% of that amounts in the 1970s and 1980s if air temperature increases 1.0 to 1.5 • C during the next 40-50 years. Some studies have reported GHG emissions in this region [42][43][44][45][46][47]. Among these studies, Miao et al [42,43] and Cui et al [44] discussed the relationship between GHG emissions and active layer depth in one peatland site.…”

“…Some studies have reported GHG emissions in this region [42][43][44][45][46][47]. Among these studies, Miao et al [42,43] and Cui et al [44] discussed the relationship between GHG emissions and active layer depth in one peatland site. Liu et al [45] studied but did not find a relationship between the active layer depth and GHG emissions.…”