| 摘要: |
| 洱海是云贵高原重要湖泊，近年来经历污染和治理过程。2017年以来，洱海全流域开展高水平保护治理，外源污染和水质发生了时空变化。为分析洱海水质的影响因素，本研究于2017年至2022年在洱海8个主要湖湾和北部、中部及南部三个湖心水域进行了连续六年的逐月水质监测，重点分析了总氮、总磷和叶绿素a浓度以及透明度四项水质指标，并用综合营养状态指数（TLI）法评价水体的富营养化程度。主要结论如下：1. 洱海水体富营养化程度呈北高南低趋势，与外源污染物主要经由北三江入湖有关；2. 2017年至2022年，南部水域富营养化程度逐年降低，中部水域氮磷浓度呈降低趋势，北部水域氮磷浓度略有升高，表明中部和南部治理成效好于北部；3. 洱海富营养化程度在汛期高于非汛期，北部水域富营养化程度的季节变异高于中部和南部水域。4. 洱海北片区及汛期污染控制和水体磷控制是洱海治理需要关注的重点问题。 |
| 关键词: 洱海 水质 富营养化 综合营养状态指数 水环境治理 |
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| The spatiotemporal variation and potential causes for the nutrient status of Erhai lake from 2017 to 2022 |
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huazhaohui,lirui,yangzhi,wenzihao,shanhang,chouqingchuan,zhangxiaolin,caote
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Institute of Hydrobiology, Chinese Academy of Sciences
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| Abstract: |
| Abstract: Erhai lake is an important lake on the Yunnan-Guizhou Plateau, which has experienced pollution and treatment in recent years. Since 2017, the high-level protection and management have been carried out in the entire Erhai lake basin, resulting in spatiotemporal changes in the external pollution and water quality. To analyze the influencing factors of external pollution on the water quality of Erhai lake, this study conducted monthly water quality monitoring in eight major bays, as well as in the central of the northern, middle, and southern parts of Erhai lake from 2017 to 2022. The concentrations of total nitrogen and phosphorus and chlorophyll-a and water transparency were measured in the water column. The eutrophication was evaluated by the trophic level index (TLI). The results showed that: 1) The TLI decreased from the northern to southern areas, in agreement with the higher nutrients input of rivers in the northern part of the lake. 2) During the period from 2017 to 2022, the trophic tatus decreased significantly in the southern area of Erhai lake and decreased slightly in the middle area, while increased in the northern area, indicating that the pollution control was more effective in the southern and middle than northern areas. 3) the trophic tatus was higher in the wet than dry seasons, and the seasonal variation of TLI was higher in the northern than middle and southern areas. 4) It is important for the control of phosphorus input into the lake, particularly for the northern area of Erhai lake basin and/or in the flooding season, as well as the phosphorus concentration in the lake water. |
| Key words: Erhai lake water quality eutrophication trophic level index water pollution control |
