| 引用本文: | 韩翠红,孙海龙,魏榆,鲍乾,晏浩.喀斯特筑坝河流中生物碳泵效应的碳施肥及对水化学时空变化的影响——以贵州平寨水库及红枫湖为例.湖泊科学,2020,32(6):1683-1694. DOI:10.18307/2020.0610 |
| HAN Cuihong,SUN Hailong,WEI Yu,BAO Qian,YAN Hao.Spatiotemporal variations of hydrochemistry in karst dammed rivers and carbon fertilization effect of biological carbon pump: A case study of Pingzhai Reservoir and Lake Hongfeng in Guizhou Province. J. Lake Sci.2020,32(6):1683-1694. DOI:10.18307/2020.0610 |
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| 摘要: |
| 耦联水生光合作用的碳酸盐风化碳汇是全球碳循环的重要组成部分，而生物碳泵效应是稳定碳酸盐风化碳汇的关键机制.河流筑坝后，生物碳泵效应的变化、控制因素及对水化学影响的研究甚少.本研究对2个喀斯特筑坝河流平寨水库和红枫湖进行系统采样，以研究河流筑坝后生物碳泵效应的变化、控制因素及对水化学的影响.研究结果表明，入库河流的水化学变化不明显，而2个水库的水化学则表现出显著的季节变化特征，具体表现为水库的水温和pH均呈现出夏季高、冬季低的变化特征，而电导率（EC）、HCO3-浓度和pCO2则表现出夏季低、冬季高的季节变化特征.以叶绿素a（Chl.a）浓度和溶解氧（DO）饱和度指代的生物碳泵效应则是在夏季最强、冬季最弱.生物碳泵效应利用溶解性无机碳（DIC），形成有机质并释放出氧气，是造成夏季水库pH值和DO饱和度升高，电导率（EC）、HCO3-浓度和pCO2降低的主要因素.空间上，水库的Chl.a浓度及DO饱和度均大于河水，EC、HCO3-浓度和pCO2均小于河水，这表明河流筑坝后，由于水库的“湖泊化”导致水库的生物碳泵效应显著提高.通过对Chl.a与碳、氮和磷浓度及化学计量比的相关性分析发现，平寨水库和红枫湖的生物碳泵效应受到碳施肥的影响.平寨水库和红枫湖水库生物碳泵效应碳施肥机制的发现，表明在喀斯特地区，生物碳泵效应不仅受到氮磷元素的控制，也受到碳元素的控制，因此在富营养化湖泊治理时，也应考虑碳的影响. |
| 关键词: 喀斯特筑坝河流 平寨水库 红枫湖 生物碳泵效应 水化学 时空变化 碳施肥 |
| DOI：10.18307/2020.0610 |
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| 基金项目:国家自然科学基金委—贵州喀斯特科学研究中心联合项目（U1612441）、国家自然科学基金项目（41977298）和中国科学院战略性先导科技专项（B类）（XDB40000000）联合资助. |
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| Spatiotemporal variations of hydrochemistry in karst dammed rivers and carbon fertilization effect of biological carbon pump: A case study of Pingzhai Reservoir and Lake Hongfeng in Guizhou Province |
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HAN Cuihong1,2, SUN Hailong1, WEI Yu1, BAO Qian1,2, YAN Hao1
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1.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, P. R. China;2.University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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| Abstract: |
| Carbonate mineral weathering coupled with aquatic photosynthesis on the continents is an important part of the global carbon cycle. The biological carbon pump is a key mechanism for stabilizing carbonate weathering-related carbon sinks. Little research has been done on the changes and control factors of biological carbon pump effects and their effects on hydrochemistry after the damming of river. In this study, two dammed karst rivers (Pingzhai Reservoir and Lake Hongfeng) were systematically sampled to study the changes and control factors of biological carbon pump effect and their effects on the variations of hydrochemistry. The results show that the hydrochemistry of the rivers have no obvious changes, while the hydrochemistry of the two reservoirs show significant seasonal variations. The temperature and pH of the two reservoirs are both higher in summer and lower in winter, while electrical conductivity (EC), HCO3- concentration and pCO2 show lower in summer and higher in winter. The biological carbon pump effect which is indicated by the chlorophyll-a (Chl.a) concentration and dissolved oxygen saturation is stronger in summer and weaker in winter. Dissolved inorganic carbon is consumed by aquatic phototrophs to form organic matter and release oxygen, which are the main factors that cause the increase of pH and dissolved oxygen (DO) in summer, and the decrease of electric conductivity (EC), HCO3- concentration, and pCO2 in winter. In the space, the Chl.a and DO concentrations of the reservoirs are larger than that in the rivers, and EC, HCO3- concentration and pCO2 are lower than that in the rivers. This indicates the biological carbon pump effect of the reservoir is significantly increased due to river impoundment after the rivers were dammed. Correlation analysis of Chl.a with carbon, nitrogen, phosphorus concentrations and stoichiometry revealed that the biological carbon pump effect of the Pingzhai Reservoir and Lake Hongfeng is affected by carbon fertilization effect. The carbon fertilization effect of biological carbon pump detected here may indicate that aquatic photosynthesis in karst damped rivers may be controlled not only by N and/or P but also by C. This research may have implications for control of eutrophication in karst lakes with high alkaline. |
| Key words: Damped karst rivers Pingzhai Reservoir Lake Hongfeng biological carbon pump effect hydrochemistry spatial and temporal variation carbon fertilization effect |
