湖北省保安湖水体营养状态监测与分析

目的] 探究湖北省保安湖水体营养状态时空特征，分析影响湖泊水体叶绿素a的主要影响因子，为其生态修复与保护提供科学依据。方法] 在湖区设置监测点位，于2019—2021年进行取样监测分析，并运用综合营养状态指数(TLI)评价湖区的营养状态。采用空间自相关分析对保安湖营养状态的空间相关性与聚集程度进行研究。通过Logit模型分析叶绿素a浓度变化的关键水环境影响因子。结果] 保安湖TLI变化范围为47.25～55.86，营养状态在中营养和轻度富营养间波动。湖区营养状态整体呈现显著的正空间自相关关系，其Global Moran’s I分别为0.46，0.93，0.60，0.31，0.60和0.62。主体湖南部是TLI的热点(高/高集聚)区域(p<0.01)，扁担塘湖区是TLI的冷点(低/低集聚)区域(p<0.01)。影响叶绿素a浓度变化的主要水环境因子排序为：透明度>TP>pH值>COD_Mn>水深>DO，均与叶绿素a浓度有显著相关性。结论] 湖区水体营养状态良好。流域内应通过控制农田水土流失及养殖业面源污染，加强入湖河道治理等方式减少外源磷输入，采用生态水位调控和修复水生植被等措施来进一步改善水体营养状态。

Monitoring and Analysis on Eutrophication Status in Baoan Lake of Hubei Province

Objective] The spatio-temporal characteristics of the eutrophication status in Baoan Lake, and the key water environmental impact factors were studied in order to provide a basis for ecological restoration and protection.Methods] Monitoring sites were set up in Baoan Lake. Sampling and monitoring were conducted from 2019 to 2021. The trophic state index (TLI) was introduced to evaluate the nutritional status of the lake, and spatial autocorrelation analysis was used to study the spatial correlation and aggregation degree of eutrophication in Baoan Lake. The main water environmental impact factors of chlorophyll a concentration were analyzed by a logit model.Results] The nutrient status of Baoan Lake fluctuated between mesotrophic and slightly eutrophic, and the range of TLI was 47.25~55.86. The eutrophication level of Baoan Lake showed significant spatial autocorrelation, with Global Moran''s I values of 0.46, 0.93, 0.60, 0.31, 0.60, and 0.62. The southern areas of the main boady of Baoan Lake were the hot spots (high/high concentration) for lake eutrophication level (p<0.01), and Biandantang lake area was the cold spot (low/low concentration) for lake eutrophication level (p<0.01). The main water environmental factors affecting the change of chlorophyll a concentration were transparency > TP > pH value > COD_Mn > water depth > DO, which were significantly correlated with chlorophyll a concentration.Conclusion] The eutrophication status of Baoan Lake water is good. Further improvement in the water nutritional status of Baoan Lake can be achieved by controlling the agricultural non-point source pollution, strengthening the management of rivers, regulating water level, recovering aquatic vegetation, and so on.