摘要
以大兴安岭北坡沼泽湿地为研究对象,通过采集原状土柱、实验室内模拟降水年际变化(R80和R130:80mm和130mm降水处理)和春季土壤冻融循环过程(培养温度:-15~5、-10~10℃和-5~15℃),评估降水和冻融对该沼泽湿地冻融期二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)交换及温室气体净收支的影响。结果表明,相对于R80处理,R130处理减少CO2 排放(P<0.05)、促进N2O(P<0.05)和CH4排放,冻融期生态系统总呼吸主导温室气体净收支,148d培养期R80和R130处理温室气体净收支分别为2 955.8±258.9 kg CO2-eq·hm^-2和1 951.1±317.3 kg CO2-eq·hm^-2,因此,丰沛降雨有利于减少冻融期该沼泽湿地对气候变化的正反馈效应。R80处理代表的常规降水条件下,冻融期CH4和N2O交换对该沼泽湿地温室气体净收支的贡献可忽略不计;R130处理代表的丰沛降水条件下,土壤冻融会激发N2O排放,使该沼泽湿地在冻融期表现为强N2O排放特征。未来对沼泽湿地土壤冻融和综合温室效应评估应特别关注降水量年际变异的影响。
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.
作者
李彦沛
黄俊翔
岳泓宇
刘春岩
江长胜
郑循华
LI Yan-pei;HUANG Jun-xiang;YUE Hong-yu;LIU Chun-yan;JIANG Chang-sheng;ZHENG Xun-hua(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;College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2019年第10期2420-2428,共9页
Journal of Agro-Environment Science
基金
国家自然科学基金国际（地区）合作与交流项目（41861134029)~~
