祁连山多年冻土区甲烷排放通量及其影响因素  

Methane flux and its influencing factors in the permafrost region of the Qilian Mountains

作　　者：毛楠 刘桂民[1] 李莉莎 李小明 张博 徐海燕[1] 吴晓东 MAO Nan;LIU Gui-min;LI Li-sha;LI Xiao-ming;ZHANG Bo;XU Hai-yan;WU Xiao-dong(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Cryosphere Research Station on the Qinghai-Tibet Plateau,State Key laboratory of Cryospheric Science,Northwest Institute of the Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州交通大学环境与市政工程学院,兰州730070 [2]中国科学院西北生态环境资源研究院,冰冻圈科学国家重点实验室,青藏高原冰冻圈观测研究站,兰州730000

出　　处：《生态学杂志》2021年第6期1745-1752,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(41661013、41871060、41861011);中国科学院西部之光项目资助。

摘　　要：全球变暖可能导致多年冻土中的有机碳分解向大气排放甲烷(CH_(4)),但多年冻土区甲烷释放通量与环境因子的关系还不清楚。本研究于2019年6月—2020年1月,选择青藏高原北部祁连山多年冻土区,利用静态箱-气相色谱法对高寒沼泽草甸、高寒草原、高寒草甸进行CH_(4)释放速率测定,并分析其与土壤理化性质的关系。结果表明:(1) CH_(4)月平均释放速率分别为:高寒沼泽草甸0.080 mg·m^(-2)·h^(-1)、高寒草原-1.132 mg·m^(-2)·h^(-1)、高寒草甸-0.541 mg·m^(-2)·h^(-1)。CH_(4)排放通量有明显的季节变化,夏季7、8月CH_(4)排放通量明显高于其他月份。(2)土壤温度与CH_(4)排放通量呈显著正相关。(3)甲烷释放速率与高寒沼泽草甸0~15 cm层土壤含水率和总碳呈正相关,与15~30 cm层土壤有机碳、总碳和总氮呈正相关。甲烷释放速率与高寒草原15~30 cm层土壤电导率呈极显著负相关。本研究表明,草甸和草原是CH_(4)的汇,植被类型是影响多年冻土区甲烷释放的主要因素,甲烷释放速率与土壤碳、氮含量、电导率和温度相关。Global warming stimulates soil organic carbon decomposition in permafrost regions,which releases methane (CH_(4)) into the atmosphere.However,the relationship between CH_(4)emission flux and environmental factors in permafrost regions is unclear.In this study,we measured the CH_(4)release rate of alpine wet meadow,alpine meadow,and alpine grassland in the permafrost region in the northern Qinghai-Tibet Plateau from June 2019 to January 2020,using static chamber-gas chromatography.We examined the relationships of CH_(4)emission and soil physical and chemical properties.The results showed that the average monthly CH_(4)release rate was0.080 mg·m^(-2)·h^(-1)in alpine wet meadow,-1.132 mg·m^(-2)·h^(-1)in alpine meadow,and-0.541 mg·m^(-2)·h^(-1)in alpine grassland.The CH_(4)emission flux showed obvious seasonal variations.The CH_(4)emission fluxes in July and August were significantly higher than that in other months.There was a positive correlation between soil temperature and CH_(4)emission flux.The rate of CH_(4)production was positively correlated with soil moisture and total carbon content in the 0-15 cm layer of alpine wet meadow,and positively correlated with the contents of soil organic carbon,total carbon,and total nitrogen in the 15-30 cm layer.The rate of CH_(4)production was negatively correlated with soil conductivity in the 15-30 cm layer of the alpine steppe.Our results indicate that meadows and grasslands are CH_(4)sinks,and that vegetation types are the main factors affecting CH_(4)release in permafrost regions.The CH_(4)release rate is related to soil carbon and nitrogen contents,electrical conductivity,and soil temperature.

关 键 词：多年冻土 甲烷通量 土壤理化性质 青藏高原 

分 类 号：X16[环境科学与工程—环境科学]