引用本文: | 邹伟,朱广伟,蔡永久,许海,朱梦圆,龚志军,张运林,秦伯强.综合营养状态指数(TLI)在夏季长江中下游湖库评价中的局限及改进意见.湖泊科学,2020,32(1):36-47. DOI:10.18307/2020.0104 |
| ZOU Wei,ZHU Guangwei,CAI Yongjiu,XU Hai,ZHU Mengyuan,GONG Zhijun,ZHANG Yunlin,QIN Boqiang.The limitations of comprehensive trophic level index (TLI) in the eutrophication assessment of lakes along the middle and lower reaches of the Yangtze River during summer season and recommendation for its improvement. J. Lake Sci.2020,32(1):36-47. DOI:10.18307/2020.0104 |
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综合营养状态指数(TLI)在夏季长江中下游湖库评价中的局限及改进意见 |
邹伟1,2, 朱广伟1, 蔡永久1, 许海1, 朱梦圆1, 龚志军1, 张运林1, 秦伯强1
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1.中国科学院南京地理与湖泊研究所, 湖泊与环境国家重点实验室, 南京 210008;2.中国科学院大学, 北京 100049
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摘要: |
综合营养状态指数(TLI)在中国湖库富营养化评价中应用非常广泛.对于该指数的各分项指标,基于叶绿素a的评估结果是富营养化风险的直接体现,是最终指示;而基于理化指标(总氮、总磷、透明度和高锰酸盐指数)的评估结果是间接指示.如果两者TLI评估结果存在显著差异,则说明基于理化参数的TLI评估结果低估或者高估了实际富营养化水平和相关风险.本文针对长江中下游湖库的基于水质理化指标和基于叶绿素a的TLI结果是否匹配的问题开展了调查分析.结果表明,对于非通江浅水湖泊而言,基于总氮、总磷、高锰酸盐指数的TLI评估结果均低估了富营养化水平和相关风险;对于通江浅水湖泊而言,基于总氮、总磷和透明度的TLI评估结果高估了富营养化水平和相关风险,而基于高锰酸盐指数的结果低估了富营养化水平;对于深水水库,基于总氮的TLI指数评估结果高估了富营养化水平,而基于总磷、透明度和高锰酸盐指数的结果低估了富营养化水平.上述水质理化指标和叶绿素a评估结果不匹配的原因为以下两点:第一,部分物理化学指标失去了对富营养化风险(叶绿素a)的指示意义,如通江浅水湖泊的总氮、总磷、透明度和高锰酸盐指数以及深水湖泊的总氮;第二,部分富营养化理化指标和叶绿素a原有关系发生错位,比如对于深水湖泊总磷对叶绿素a的响应比TLI指数构建所采用的关系更加敏感.针对TLI理化指标评估在长江中下游湖库应用中存在的问题提出如下改进建议:1)结合长时间序列历史数据,基于分位数回归等方法构建特定湖泊的叶绿素a和理化参数的响应关系,开发“一湖一策”的评估公式;2)根据换水周期和湖泊面积水深比对进行湖泊分类,建立特定湖泊类型的叶绿素a和理化参数的响应关系,构建“一类一策”的评估公式;3)在富营养化评估结果中应分别量化富营养化状态参数(营养盐水平)和富营养化风险参数(叶绿素a)以及两者比值,但生物指标是富营养化评估的最终指示.现阶段我国富营养化评价和管理多为“全国一策”,可能很难满足经济高效的管理需求.因此,本研究所建议和综述的“一类一策”和“一湖一策”的湖泊富营养化评估方法对未来的湖泊生态管理可能具有重要意义. |
关键词: 富营养化评估 浅水湖泊 营养盐 “一类一策” 长江中下游 |
DOI:10.18307/2020.0104 |
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基金项目:中国科学院战略性先导科技专项(A类)(XDA23040201)、中国科学院重点部署项目(ZDRW-ZS-2017-3-4)和国家自然科学基金项目(41671494,41830757)联合资助. |
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The limitations of comprehensive trophic level index (TLI) in the eutrophication assessment of lakes along the middle and lower reaches of the Yangtze River during summer season and recommendation for its improvement |
ZOU Wei1,2, ZHU Guangwei1, CAI Yongjiu1, XU Hai1, ZHU Mengyuan1, GONG Zhijun1, ZHANG Yunlin1, QIN Boqiang1
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1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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Abstract: |
The comprehensive trophic level index (TLI) is widely used in eutrophication assessment of Chinese lakes. For each sub-indices of TLI, the chlorophyll-a is the final indication due to its direct manifestation of eutrophication-related risk, and the physiochemical indicators (total nitrogen, total phosphorus, Seccchi depth and permanganate index) are indirect indications. Thus, the significant difference between the values of TLI based on the physicochemical indicators and chlorophyll-a indicates that the results based physicochemical indicators over-or underestimate the actual eutrophication status and associated risk. Here, the TLI assessment results of lakes along the middle and lower reaches of the Yangtze River based on the four physicochemical indicators and on chlorophyll-a were compared. Our results showed that, for Yangtze-isolated shallow lakes, the assessment results of TLI based on total nitrogen, total phosphorus and permanganate index underestimated the actual eutrophication status and associated risk. For Yangtze-connected shallow lakes, the results of TLI based on total nitrogen, total phosphorus, and Secchi depth overestimated the eutrophication status and associated risk, while the results based on the permanganate index underestimated the eutrophication level and associated risk. For the deep reservoirs, the evaluation of TLI based on the total nitrogen overestimated the level of eutrophication and associated risk, while the results based on the rest three physiochemical indicators underestimated the eutrophication status. The reasons for the mismatch of assessment results between the physicochemical indicators and chlorophyll-a are ascribed to two aspects. For specific lake type, some physicochemical parameters have limited indication for eutrophication risk (chlorophyll-a). Such as total nitrogen, total phosphorus, Secchi depth and permanganate index in Yangtze-connected and the total nitrogen in deep reservoirs. Moreover, the original relationships between physicochemical indicators and chlorophyll-a is mismatched. For example, the response of TP to chlorophyll-a in deep lakes is more sensitive than the counterpart used in development of TLI (TP) formula. The following suggestions were proposed for the lake eutrophication assessment of the middle and lower reaches of the Yangtze River. 1) for the lakes with adequate historical dataset, establishing the lake-specific relationships between chlorophyll-a and the four physiochemical indicators through quantile regression model and developing the lake-specific evaluate formula for physiochemical indicators; 2) Making the lake subdivision based on the water retention time and water area/water depth and deriving the type-specific relationships between chlorophyll-a and physiochemical indicators, obtaining the type-specific evaluate formula for physiochemical indicators of lakes in the middle and lower reaches of the Yangtze river. 3) In the results of eutrophication assessment, the state indicators (e.g., total nitrogen and total phosphorus) and risk indicator (i.e., chlorophyll-a) may should be evaluated separately, and more attention should be paid into the ratio of chlorophyll-a to nutrient in the lake eutrophication assessment. Meanwhile, the final indication of biological indicators needs to be emphasized. Given the fact that a general eutrophication management framework was currently implemented for Chinese lakes, which may be difficult to meet cost-efficient management objective. Thus, the type-specific and lake-specific eutrophication assessment methods proposed and reviewed in this study may be of great significance in future lake management. |
Key words: Eutrophication evaluation shallow lakes nutrient type-specific strategy middle and lower reaches of the Yangtze River |
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