Methane Emissions Offset Net Carbon Dioxide Uptake From an Alpine Peatland on the Eastern Qinghai‐Tibetan Plateau
Haijun Peng, Jinshu Chi, Yao Hu, Qian Guo, Bing Hong, Hanwei Ding, Yongxuan Zhu, Jie Wang, Yetang Hong
Abstract
Abstract Peatlands store large amounts of carbon (C) and actively exchange greenhouse gases (GHGs) with the atmosphere, thus significantly affecting global C cycle and climate. Large uncertainty exists in C and GHG estimates of the alpine peatlands on Qinghai‐Tibetan Plateau (QTP), as direct measurements of CO 2 and CH 4 fluxes are scarce in this region. In this study, we provided 32‐month CO 2 and CH 4 fluxes measured using the eddy covariance (EC) technique in a typical alpine peatland on the eastern QTP to estimate the net C and CO 2 equivalent (CO 2 ‐eq) fluxes and investigate their environmental controls. Our results showed that the mean annual CO 2 and CH 4 fluxes were −68 ± 8 g CO 2 ‐C m −2 yr −1 and 35 ± 0.3 g CH 4 ‐C m −2 yr −1 , respectively. While considering the traditional and sustained global warming potentials of CH 4 over the 100‐year timescale, the peatland acted as a net CO 2 ‐eq source (1,059 ± 30 and 1,853 ± 31 g CO 2 ‐eq m −2 yr −1 , respectively). The net CO 2 ‐eq emissions during the non‐growing seasons contributed to over 40% of the annual CO 2 ‐eq budgets. We further found that net CO 2 ‐eq flux was primarily influenced by global radiation and soil temperature variations. This study was the first assessment to quantify the net CO 2 ‐eq flux of the alpine peatland in the QTP region using EC measurements. Our study highlights that CH 4 emissions from the alpine peatlands can largely offset the net cooling effect of CO 2 uptake and future climate changes such as global warming might further enhance their potential warming effect.