| 摘要: |
| 基于2019-2023年金沙江向家坝水库干、支流20个断面的叶绿素a(Chl.a)及相关环境因子的月度数据,运用数理统计、相关性分析、逐步回归、通径分析等方法,探究了向家坝水库Chl.a的时空分布特征及其与环境因子的关系。研究表明,向家坝水库Chl.a 5年平均含量3.91μg/L,年际间Chl.a含量呈波动变化无明显规律,季节方面,春、夏、秋三季Chl.a含量均显著高于冬季；空间分布上,支流库湾Chl.a含量高于干流,干流年均Chl.a含量沿程呈现上升趋势,且干流坝前江段Chl.a含量高于坝后江段,支流库湾人口相对集中的断面Chl.a年均含量较高。Pearson相关分析、逐步回归分析、通径分析结果均表明,不同年份、不同季节、不同断面影响Chl.a含量的环境因子不尽相同,存在时间及空间差异。Pearson相关分析表明,研究期间向家坝水库全库Chl.a与TP、PO43--P、NH3-N、NO3--N、TN、CODMn、T、WT、DO、pH显著正相关,与SD、Cond、V显著负相关。逐步回归分析筛选出对库区整体Chl.a含量影响显著的8个环境因子分别为TN、PO43--P、TP、pH、DO、CODMn、SD、T,除SD与Chl.a含量呈极显著负相关外,其余环境因子均与Chl.a含量正相关；而通径分析决策系数则表明CODMn、TN、SD是影响向家坝水库Chl.a含量最主要的环境因子。分析表明,pH、DO、CODMn、SD为影响向家坝水库Chl.a含量的被动因子,TN、PO43--P、TP等营养盐为限制性因子,温度则为关键因子。本研究对掌握向家坝水库浮游植物生长情况、了解其水体营养状态具有重要意义，同时也可为金沙江下游巨型梯级水库水环境研究提供一定的参考依据。 |
| 关键词: 向家坝水库 叶绿素a 逐步回归分析 通径分析 |
| DOI： |
| 分类号: |
| 基金项目:中国长江三峡集团有限公司技术服务项目（0711541、0711556、0711572）、中国长江三峡集团有限公司员工科研项目（NBYG202200449） |
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| Spatiotemporal characteristics of chlorophyll-a and its influencing factors in Xiangjiaba Reservoir from 2019 to 2023 |
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Liu Fangzhi, Zhao Mingliang, Huang Yubo, Pan Zeng, Zhang Yong, Zhou Ling
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River Basin Complex Administration Center,China Three Gorges Corporation
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| Abstract: |
| Spatiotemporal characteristics of chlorophyll-a(Chl.a) and its influencing factors in Xiangjiaba Reservoir were explored by using mathematical statistics, correlation analysis, stepwise regression, path analysis and other methods from 2019 to 2023.The results showed that the annual average concentration of Chl.a in Xiangjiaba Reservoir was 3.91 μg/L, and the annual variation of Chl.a concentration was irregular. About seasons, the overall characteristics showed that the concentration of Chl.a was significantly higher in spring, summer and autumn than in winter.The Chl.a concentration in the tributary was higher than that in the main stream. The annual average Chl.a concentration increased gradually from the upstream to the downstream of the main stream,and the chl.a concentration of the section with many people in the tributary was higher.Pearson correlation analysis, stepwise regression analysis and path analysis showed that there were temporal and spatial differences in environmental factors affecting Chl.a concentration in different years, seasons and sections.Pearson correlation analysis showed that Chl.a concentration in Xiangjiaba Reservoir was significantly positively correlated with TP,PO43--P,NH3-N,NO3--N,TN,CODMn,T,WT,DO and pH, and significantly negatively correlated with SD,Cond and V.Stepwise regression analysis showed that the eight environmental factors that had significant impact on the overall Chl.a concentration in the reservoir area were TN,PO43--P,TP,pH,DO,CODMn,SD and T,and the environmental factors were positively correlated with Chl.a concentration except SD.The path analysis decision coefficient shows that CODMn, TN and SD were the most important environmental factors affecting the concentration of Chl.a in Xiangjiaba Reservoir.The final analysis showed that pH, DO, CODMn and SD were the passive factors affecting the concentration of Chl.a in Xiangjiaba Reservoir, while TN, PO43--P, TP and other nutrients were the limiting factors, and temperature was the key factor.This result can further understand the growth of phytoplankton and the nutrient status of water in Xiangjiaba Reservoir, and also can provide a reference for the water environment research of the Jinsha River cascade reservoirs. |
| Key words: Xiangjiaba Reservoir Chlorophyll-a Stepwise regression analysis Path analysis |
