| 摘要: |
| 富营养化水体的碳通量过程一直是全球水域生态系统中的前沿和热点问题.本研究以三峡大学校园内景观池塘(莲心湖)为研究对象,开展为期一年的水-气界面CH4通量监测,并在此基础上进一步探讨水体富营养化水平对CH4释放的影响.结果表明莲心湖水-气界面CH4平均排放通量为5.06 mg/(m2·h),整体表现为CH4的源,且冒泡释放为主导(占比为88.56%).CH4排放通量呈现时间异质性,表现为夏季(8.70 mg/(m2·h))>冬季(4.80 mg/(m2·h))>春季(3.88 mg/(m2·h))>秋季(2.87 mg/(m2·h)),白天(0.11 mg/(m2·h))略高于夜晚(0.09 mg/(m2·h)).CH4排放通量在各个季节及昼夜的差异与温度、风速和叶绿素a等环境因素变化有关.随着水体富营养化水平的提高,CH4排放通量呈现非线性增加的趋势,重度富营养化水体的CH4排放通量是中度富营养化水体的2倍,这表明降低水体富营养化水平可有效减少水体的CH4排放,可为其他同类型水体的温室气体减排提供参考. |
| 关键词: 富营养化 甲烷释放 池塘 冒泡通量 叶绿素a |
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| Methane Emission Characteristics in Typical Artificial Landscape Pond and its Response to Eutrophication |
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LAI Shi-ping, Liu Jia, Xiao Shang-bin, Chen Min, Zhang Bo-wen, Meng Jiang-huai, Li Yuan-zheng
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College of Hydraulic and Environmental Engineering, China Three Gorges University
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| Abstract: |
| The carbon flux process in eutrophic water bodies has always been a prominent and critical concern in global aquatic ecosystems. This study conducted a year-long in-situ investigation of methane (CH4) flux at the water-air interface in the campus landscape pond (Lianxin Pond) of Three Gorges University. The aim was to assess the influence of eutrophication levels on CH4 emissions. The findings revealed a CH4 emission flux rate of 5.06 mg/(m2·h) at the water-air interface, contributing to atmospheric CH4 levels. The CH4 flux was influenced by temperature, wind speed, and chlorophyll-a, while showed significant temporal heterogeneity with the following order: summer (8.70 mg/(m2·h)) > winter (4.80 mg/(m2·h)) > spring (3.88 mg/(m2·h)) > autumn (2.87 mg/(m2·h)). Furthermore, the dominant pathway was identified as bubbling(the proportion of bubbling is 88.56%), during the day (0.11 mg/m2 (h.)) slightly higher than the night (0.09) mg/(m2·h)). The difference of CH4 emission flux in different seasons and day and night is related to the change of environmental factors such as temperature, wind speed and chlorophyll. With the increase of water eutrophication level, the CH4 emission flux showed a non-linear increase trend. With the increase of eutrophication level, the release flux of CH4 release flux showed nonlinear increase. Notably, in hyper-eutrophic water, the mean CH4 flux was 2 times greater than in moderately eutrophic water. Reducing the eutrophication degree is the key to reducing CH4 emissions from water bodies and can serve as a reference for lowering greenhouse gas emissions in other similar aquatic ecosystems. |
| Key words: Eutrophication Methane emission pond bubbling chlorophyll-a |
