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| Effects of precipitation and soil freeze-thaw cycles on greenhouse gas exchanges in a permafrost swamp of the Great Hing'an Mountains, China |
| Received:April 24, 2019 |
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| KeyWord:permafrost;swamp;precipitation;nitrous oxide;net greenhouse gas budget |
| Author Name | Affiliation | E-mail | | LI Yan-pei | College of Resources and Environment, Southwest University, Chongqing 400716, China
State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | | | HUANG Jun-xiang | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China | | | YUE Hong-yu | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China | | | LIU Chun-yan | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | lcy@post.iap.ac.cn | | JIANG Chang-sheng | College of Resources and Environment, Southwest University, Chongqing 400716, China | | | ZHENG Xun-hua | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China | |
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| Abstract: |
| Permafrost in China is mainly distributed in the Qinghai-Tibetan Plateau and Northeast China. Swamps are one of the most typical ecosystems in permafrost regions of the Great Hing'an Mountains. Soil freeze-thaw as a common natural phenomenon may greatly influence greenhouse gas exchanges in the permafrost swamps. In this study, we took intact soil cores from a typical swamp in the Great Hing'an Mountains and evaluated the effects of precipitation and soil freeze-thaw cycles on greenhouse gas fluxes and net greenhouse gas budgets(NGHGBs)through simulation experiments in laboratory. The treatment with 130 mm rainfall(hereafter referred to as R130)decreased carbon dioxide(CO2)emissions(P<0.05), and increased nitrous oxide(N2O, P<0.05)and methane(CH4)emissions compared with the treatment with 80 mm rainfall(hereafter referred to as R80). The ecosystem respiration dominated NGHGBs and hence, the swamp had positive radiation forcing effects during the freeze-thaw period. The NGHGBs during the incubation period of 148 d were 2 955.8±258.9 kg CO2-eq·hm-2 and 1 951.1±317.3 kg CO2-eq·hm-2 in the R80 and R130 treatments, respectively, which indicated that abundant precipitation was beneficial to mitigate the positive feedback of greenhouse gas emissions during the freeze-thaw period on climate change. The contributions of CH4 and N2O exchanges on the NGHGBs during the freeze-thaw period were negligible in the R80 treatment. However, soil freeze-thaw stimulated N2O emissions from the permafrost swamp in the R130 treatment. The studies on freeze-thaw-induced N2O emissions and NGHGBs in permafrost swamps should consider the effects of inter-annual variations of precipitation on greenhouse gas exchanges. |
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