| 引用本文: | 任艺洁,邓正苗,谢永宏,朱莲莲,陈晓蓉,张称意,陈心胜,李峰,邹业爱.洞庭湖湿地洪水期甲烷扩散和气泡排放通量估算及水环境影响分析.湖泊科学,2019,31(4):1075-1087. DOI:10.18307/2019.0418 |
| REN Yijie,DENG Zhengmiao,XIE Yonghong,ZHU Lianlian,CHEN Xiaorong,ZHANG Chengyi,CHEN Xinsheng,LI Feng,ZOU Ye'ai.Estimation of methane diffusion and ebullition flux and water environmental controls during flooding period in Lake Dongting wetlands. J. Lake Sci.2019,31(4):1075-1087. DOI:10.18307/2019.0418 |
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| 洞庭湖湿地洪水期甲烷扩散和气泡排放通量估算及水环境影响分析 |
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任艺洁1,2,3, 邓正苗1,2, 谢永宏1,2, 朱莲莲1,2,3, 陈晓蓉1,2,3, 张称意4, 陈心胜1,2, 李峰1,2, 邹业爱1,2
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1.中国科学院亚热带农业生态研究所农业生态过程重点实验室, 长沙 410125;2.中国科学院亚热带农业生态研究所, 中国科学院洞庭湖湿地生态系统观测研究站, 长沙 410125;3.中国科学院大学, 北京 100049;4.中国气象局国家气候中心, 北京 100081
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| 摘要: |
| 水体甲烷（CH4）主要通过气泡和扩散传输排放到大气，这两种途径在CH4总排放中的相对贡献及环境影响因子目前关注较少.本文以洞庭湖湿地3种生境类型（光滩、苔草、芦苇）为研究对象，通过静态箱法和扩散模型法估算洪水期CH4总排放通量、扩散排放通量和气泡排放通量，并分析其水体环境因子影响.结果表明：苔草地CH4总排放量最高，为6.49±3.12 mg（C）/（m2·h）.在3个生境中，CH4扩散排放占总排放通量的1.34%~3.91%，气泡排放占96.09%~98.66%.扩散排放通量受水体pH、电导率和水温的影响，而CH4的总排放和气泡排放主要受水温的影响.当水温低于11.7℃时，水体CH4以扩散排放为主，但当水温高于11.7℃时，水体CH4主要通过气泡排放.但这一温度阈值是否同样适用于其他类型湿地还需要更多实验验证.本研究对于揭示中低纬度内陆湖泊水体CH4排放过程有重要意义. |
| 关键词: 甲烷通量 气泡传输 扩散传输 水温 洞庭湖湿地 |
| DOI：10.18307/2019.0418 |
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| 基金项目:国家自然科学基金项目（41401290）、中国科学院亚热带农业生态研究所青年创新团队（2017QNCXTD_LF）和中国气象局东北地区生态气象创新开放实验室课题（STQX201703）联合资助. |
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| Estimation of methane diffusion and ebullition flux and water environmental controls during flooding period in Lake Dongting wetlands |
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REN Yijie1,2,3, DENG Zhengmiao1,2, XIE Yonghong1,2, ZHU Lianlian1,2,3, CHEN Xiaorong1,2,3, ZHANG Chengyi4, CHEN Xinsheng1,2, LI Feng1,2, ZOU Ye'ai1,2
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1.Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, P. R. China;2.Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, P. R. China;3.University of Chinese Academy of Sciences, Beijing 100049, P. R. China;4.National Climate Center, China Meteorological Administration, Beijing 100081, P. R. China
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| Abstract: |
| The main pathways of CH4 exchange between air and water are molecular diffusion and ebullition. However, the relative contribution of these two pathways to total methane emissions and their environmental controls are far from clear. In this paper, by using float static chamber and diffusion model, we measured the CH4 total emission flux (Ftotal), diffusion flux (Fdiff) and ebullitive flux (Febul) in three types of habitats (mudflat, Carex meadow and reed land) in Lake Dongting wetlands during flooding period. Further, the environmental controls on CH4 flux were analyzed through stepwise regression and linear regression model. The results showed that total CH4 emission flux was the highest in Carex meadow (6.49±3.12 mg (C)/(m2·h)) among three habitat types. The CH4 diffusion fluxes accounts for 1.34% to 3.91% to total CH4 emissions in the three sites, while the ebullitive flux contributed 96.09% to 98.66% to total CH4 emissions. The stepwise regression analysis between CH4 emission and environmental factors showed that CH4 diffusion flux was affected by water pH, conductivity and water temperature, while the total CH4 emission flux and CH4 ebullitive flux were mainly affected by water temperature. Furthermore, we found that water temperature determines the dominant emission pathway:when the water temperature was below 11.7℃, diffusion was the main way for CH4 emission otherwise ebullition pathway dominant the CH4 emission. However, whether this temperature threshold is equally applicable to other types of wetlands still requires more experimental verification. This study is important for revealing the mechanism of CH4 emissions in tropical and subtropical lakes. |
| Key words: CH4 flux ebullition diffusion water temperature Lake Dongting wetlands |
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