| 摘要: |
| 为明确汉丰湖叶绿素a（Chlorophyll a，Chl-a）的主要影响因素，分析了汉丰湖2018—2021年的Chl-a、pH、水温（Temperature，T）、透明度（Secchi Depth，SD）、氮（Nitrogen，N）、磷（Phosphorus，P）营养盐等水质指标的变化情况，探讨了Chl-a与其余水质指标的相关性，并应用结构方程模型解析了Chl-a的关键影响因素。结果表明，汉丰湖水体Chl-a浓度在0.04~68.58 μg/L变化，T在9.62~32.10℃范围变化，pH在6.75~9.81间变化，而总氮（Total Nitrogen，TN）、溶解性氮（Dissolved Nitrogen，DN）、总磷（Total Phosphorus，TP）、溶解性磷（Dissolved Phosphorus，DP）的变化范围分别为0.58~4.68、0.25~3.99、0.02~0.76、0.01~0.44 mg/L。Chl-a浓度与T、pH、TP和总固体悬浮物（Total solid suspension, TSS）呈显著正相关（P<0.05），与SD、DN、碱度（Alkalinity，ALK）、亚硝态氮（Nitrite nitrogen，NO2--N）、硝态氮（Nitrate nitrogen，NO3--N）呈极显著负相关（P<0.01）。结构方程模型结果显示，影响Chl-a浓度的因子中理化因子的路径系数为0.68，营养物质的路径系数为0.16，这表明影响Chl-a浓度的因子以理化因子为主，营养物质的作用相对较小。同时，理化因子通过营养盐间接影响Chl-a浓度（路径系数为–0.04）。各理化因子中，T和pH的路径系数分别为0.51和0.41，T是理化因子的主要表征指标；在营养盐指标中，TP和DP的路径系数分别为0.82和0.71，而TN的路径系数为0.36，说明P是汉丰湖的限制性营养元素。 |
| 关键词: 水体富营养化 影响因子 结构方程模型 浮游植物 三峡库区 |
| DOI： |
| 分类号: |
| 基金项目:(U20A20326)；国务院三峡建设委员会办公室生态与环境系统重点支流水质监测项目(JJ2015-016) |
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| Identification of the relationship between chlorophyll-a and its key influencing factors in Hanfeng Lake in the Three Gorges Reservoir based on structural equation model |
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Yang Baoxiang, Xu Qiwen, He Binghui, Zhao Xiulan, Li Tianyang, Fu Shi, Qian Tian, Wu Haochen, Zhu Shunyao
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College of Resources and Environment,Southwest University
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| Abstract: |
| To determine the key influence factors of chlorophyll-a (Chl-a) in the Hanfeng Lake, the changes of water temperature (T), pH, Chl-a, Secchi Depth (SD), and nitrogen (N) and phosphorus (P) nutrients in Hanfeng Lake from 2018 to 2021 were analyzed, and the correlation between Chl-a and other water quality indicators was revealed, and the key influencing factors of Chl-a were analyzed by the structural equation model. The results showed that the Chl-a in Hanfeng Lake ranged from 0.04 to 68.58 μg/L, and the water temperature (T) ranged from 9.62 to 32.10℃, the pH ranged from 6.75 to 9.81. Total nitrogen (TN), dissolved nitrogen (DN), total phosphorus (TP) and dissolved phosphorus (DP) in the Hanfeng Lake varied from 0.58 to 4.68, 0.25 to 3.99, 0.02 to 0.76 and 0.01 to 0.44 mg/L. Chl-a concentration was positively correlated with T, pH, TP and total suspended solids (TSS) (P<0.05). Conversely, Chl-a concentration was negatively correlated with alkalinity (ALK), DN, nitrate nitrogen (NO3–-N), nitrite nitrogen (NO2–-N) and SD (P<0.01). The structural equation model results showed that the path coefficient of physical factor in the factors affecting Chl-a concentration was 0.68 and nutrients 0.16, indicating that the factors affecting Chl-a concentration are mainly physical factor and the nutrients are less role. Meanwhile, physical factor indirectly affect Chl-a concentration through nutrient salts (path coefficient is -0.04). In each physical factor, the path coefficient of T and pH is 0.51 and 0.41, respectively, T is the main characterization index of the physical factor; the path coefficients of TP and DP are 0.82 and 0.71, respectively, while the path coefficient of TN is 0.36, P is a limiting nutrient element of Hanfeng Lake. |
| Key words: eutrophication influence factors structural equation model phytoplankton Three Gorges Reservoir Area |
