| 引用本文: | 余晓,诸葛亦斯,刘晓波,杜强,谭宏.大型深水水库溶解氧层化结构演化机制.湖泊科学,2020,32(5):1496-1507. DOI:10.18307/2020.0521 |
| YU Xiao,ZHUGE Yisi,LIU Xiaobo,DU Qiang,TAN Hong.Evolution mechanism of dissolved oxygen stratification in a large deep reservoir. J. Lake Sci.2020,32(5):1496-1507. DOI:10.18307/2020.0521 |
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| 摘要: |
| 深水水库溶解氧（DO）的演化成因目前尚不完全清楚，研究其演变机制对制定水库水质保护和管理策略十分重要.本文以我国京津冀地区重要的大型深水水源水库潘家口水库为例，系统分析了水库水温和DO浓度的时空分布特征、演化成因，以及水库的水质响应情况.结果表明：4月中旬-11月底该水库存在显著的季节性热分层，水库热分层为DO层化结构的形成提供了垂向分异性物理环境；与热分层类似，DO层化表现为3层结构，本文从上至下将其分别定义为混合层、氧跃层和氧亏层.垂向各层不同生化过程的作用为DO浓度空间差异性演变提供了驱动力，其中混合层受浮游藻类过量生长的影响，DO往往处于过饱和状态；氧跃层受大量生物的呼吸及有机物分解等耗氧的影响，DO浓度急剧下降，7—8月一般处于缺氧状态（DO<2 mg/L）；氧亏层受重污染沉积物耗氧的影响，DO浓度持续下降，热分层末期水库底部可能出现缺氧.热分层末期DO浓度降低的同时，沉积物中会发生Mn的还原、Mn-P解吸释放等现象，但沉积物中含量较高的Fe没有发生还原以及Fe-P的解吸释放现象.潘家口水库目前正在逼近缺氧、内源污染大量释放的临界点，其水环境治理应予以高度重视. |
| 关键词: 溶解氧层化结构 演化机制 深水水库 潘家口水库 |
| DOI：10.18307/2020.0521 |
| 分类号: |
| 基金项目:国家重点研发计划项目（2016YFC0401701）资助. |
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| Evolution mechanism of dissolved oxygen stratification in a large deep reservoir |
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YU Xiao1, ZHUGE Yisi1, LIU Xiaobo1, DU Qiang1, TAN Hong2
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1.China Institute of Water Resources and Hydropower Research, Beijing 100038, P. R. China;2.Guangzhou Institute of Water Sciences, Guangzhou 510220, P. R. China
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| Abstract: |
| The cause of dissolved oxygen (DO) evolution in deep reservoirs still remains unclarified. However, it is important to explore the evolutionary mechanism for water quality protection and management. This paper systematically analyzed the spatiotemporal variations of water temperature and DO, as well as the water quality response to these factors, in the Panjiakou Reservoir, a large deep reservoir in Beijing-Tianjin-Hebei region. Results show that the reservoir has a significant seasonal thermal stratification during mid-April to the end of November, which creates a vertically specific environment for the DO stratification. Similar to the thermal stratification, the DO stratification also shows a three-layer structure from top to down, namely, the mixed layer, the oxycline and the oxygen-deficient layer. Different biochemical processes in each layer determinate the spatial variability DO evolution. Due to excessive planktonic algae, DO is supersaturated in the mixed layer. While in the oxycline layer, DO concentration declines sharply as a result of respiration and organic matter decomposition, becoming hypoxic (i.e., DO<2 mg/L) in July and August. Due to the oxygen consumption of severely contaminated sediments in the oxygen-deficient layer, DO concentration declines continuously, potentially leading to hypolimnion at the bottom of the reservoir at the end of thermal stratification. Meanwhile, in this area, Mn reduction reaction occurs and the Mn-P is released to the hypolimnion. However, there is no Fe reduction reaction or Fe-P released. In summary, the Panjiakou Reservoir is approaching a critical point of hypoxia and massive release of endogenous pollutants. Special attentions should be paid on its water environment treatment. |
| Key words: Dissolved oxygen stratification evolution mechanism deep water reservoirs Panjiakou Reservoir |
