| 引用本文: | 张璐,荀凡,沈悦,柯凡,杜先,陈新芳,冯慕华.持续性高藻输入河道温室气体时空排放特征及其影响因素.湖泊科学,2022,34(3):752-765. DOI:10.18307/2022.0305 |
| Zhang Lu,Xun Fan,Shen Yue,Ke Fan,Du Xian,Chen Xinfang,Feng Muhua.Spatiotemporal emission characteristics and influencing factors of greenhouse-gas emissions in persistent algae-input channels. J. Lake Sci.2022,34(3):752-765. DOI:10.18307/2022.0305 |
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| 持续性高藻输入河道温室气体时空排放特征及其影响因素 |
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张璐1,2, 荀凡2,3, 沈悦2,3, 柯凡2, 杜先2, 陈新芳1, 冯慕华2
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1.河海大学水文水资源学院, 南京 210098;2.中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008;3.中国科学院大学, 北京 100049
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| 摘要: |
| 淡水水生生态系统是大气中温室气体气体重要的“源”，对于城市的动脉——城市河流（尤其是持续性高藻输入河道）温室气体的研究比较匮乏.太湖梅梁湖的高藻水排入地梁溪河是典型的高藻输入河道，月均藻密度为3.6×107 cells/L，夏季日均藻密度为1.2×108 cells/L.本文以梁溪河为研究对象，采用静态箱法测定了梁溪河河道CH4、CO2通量，分析其特征及影响因素.结果表明：1）空间尺度上，各断面CH4气体通量平均值为4.63 μmol/（m2·s），CO2气体通量平均值为98.87 μmol/（m2·s）.CH4在各断面均呈释放态，CO2除在梅梁湖泵站处呈吸收态外，在其余各点位同样呈释放态；2）对鸿桥点位进行温室气体通量的日尺度观测发现，CH4通量日变化峰值出现在傍晚，CO2通量日变化峰值出现在正午前后，昼夜变化不明显；3）影响梁溪河CH4通量变化的主要因素为河道流速、水体溶解氧浓度和固体悬浮物浓度，影响梁溪河CO2通量变化的主要因素为河道流速、水体溶解氧浓度、氧化还原电位和pH值，另外河道的水动力条件和蓝藻堆积密度成为影响温室气体排放的关键因子.梁溪河作为典型的高藻输入河道，其温室气体排放量显著高于世界河流平均气体排放量（CO2释放平均值为7.65 μmol/（m2·s），CH4释放平均值为0.1 μmol/（m2·s））.因此，持续性高藻输入河道温室气体排放机制的研究对准确评估全球河流碳排放具有重要理论支撑作用. |
| 关键词: 高藻河道|温室气体|水动力|时空排放特征|太湖|梅梁湖 |
| DOI：10.18307/2022.0305 |
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| 基金项目:国家自然科学基金项目（41877482，41471075）、国家水体污染控制与治理科技重大专项（2017ZX07603-005，2017ZX07203-003）和江苏省高校水处理技术与材料协同创新中心项目联合资助. |
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| Spatiotemporal emission characteristics and influencing factors of greenhouse-gas emissions in persistent algae-input channels |
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Zhang Lu1,2, Xun Fan2,3, Shen Yue2,3, Ke Fan2, Du Xian2, Chen Xinfang1, Feng Muhua2
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1.College of Hydrology and Water Resources, Hohai University, Nanjing 210098, P. R. China;2.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;3.University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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| Abstract: |
| Freshwater aquatic ecosystem is an important source of greenhouse gases emission in the atmosphere. There is little research on greenhouse gases in urban artery-urban rivers (especially the channels with persistent high algae input). The discharge of high algae from Meiliang Bay of Lake Taihu into Liangxi River is a typical channel of high algae input, with a monthly averaged algae density of 3.6×107 cells/L and a daily averaged algae density of 1.2×108 cells/L in summer. In this paper, the fluxes of methane and carbon dioxide in Liangxi River were measured by static chamber method, and their characteristics and influencing factors were analyzed. The results show that on the spatial scale, the average methane flux is 4.63 μmol/(m2·s), and the average carbon dioxide flux is 98.87 μmol/(m2·s). Methane was released at all sections, and carbon dioxide was released at all points except the absorption state at Meiliang Bay pumping station. The diurnal observation of greenhouse gas flux at Hongqiao site shows that the peak value of methane flux appears in the evening, and the peak value of carbon dioxide flux appears around noon, and the diurnal variation is not obvious. The main factors influencing the beam river methane flux variation were river flow velocity, dissolved oxygen and suspended solids contents, Redox potential and pH value, hydrodynamic conditions and cyanobacteria packing density become the key factors affecting greenhouse gas emissions. The Liangxi River, as a typical algal input channel, exhibited much higher greenhouse gas emissions above the world average (carbon dioxide emission is 7.65 μmol/(m2·s), methane emission is 0.1 μmol/(m2·s)). Therefore, the study of greenhouse gas emission mechanism from persistent high algae input channels is of important theoretical support for accurate assessment of global river carbon emissions. |
| Key words: Algae-laden channels|greenhouse gases|hydrodynamics|temporal and spatial emission characteristics|Lake Taihu|Meiliang Bay |
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