| 引用本文: | 朱广伟,秦伯强,张运林,李渊,朱梦圆,许海,张毅博.近70年来太湖水体磷浓度变化特征及未来控制策略.湖泊科学,2021,33(4):957-973. DOI:10.18307/2021.0401 |
| Zhu Guangwei,Qin Boqiang,Zhang Yunlin,Li Yuan,Zhu Mengyuan,Xu Hai,Zhang Yibo.Fluctuation of phosphorus concentration in Lake Taihu in the past 70 years and future control strategy. J. Lake Sci.2021,33(4):957-973. DOI:10.18307/2021.0401 |
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| 近70年来太湖水体磷浓度变化特征及未来控制策略 |
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朱广伟1, 秦伯强1, 张运林1, 李渊2, 朱梦圆1, 许海1, 张毅博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, 太湖湖泊生态系统研究站, 南京 210008;2.浙江工商大学旅游与城乡规划学院, 杭州 310018
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| 摘要: |
| 分析湖泊中磷浓度的变化特征，揭示其变化的驱动机制，是有效实施湖泊水体磷浓度控制的前提.本文整理分析了太湖70年来（1949—2020年）水体磷浓度监测历史资料，对比了太湖不同湖区、不同时间尺度水体磷浓度的差异性及波动性，发现影响太湖磷浓度变化的原因既有人为的因素，也有自然的因素.无论是污染较轻的1950年，还是污染负荷相对较重的近30年，太湖水体磷浓度一直存在较大时空差异性.暴雨引发入湖河流携带磷污染的扩散、风浪扰动引起的内源释放及蓝藻水华期间藻类生物量的大幅时空变化，都加剧了太湖水体磷浓度的不稳定性.近20年的太湖水污染治理对磷浓度的时空分布影响明显，1998年的太湖水污染治理“零点行动”，2007年以来的水利调度等系列水污染治理工程，以及2017年以来的藻情变化等，都对太湖水体磷浓度的时空格局产生了影响.然而，高强度治理投入下太湖水体磷浓度依然偏高，其原因与流域建设用地比例增加、人口增加、耕地种植结构变化等外源负荷因素发生变化有关，也与湖体沉水植被退化、出入流结构发生变化、气候变化引发的蓝藻水华扩张等内源强度及水体表观磷浓度决定因素的生态环境变化有关.近70年来太湖水体磷浓度的变化过程对类似大型浅水湖泊的磷控制策略具有启示意义：大型浅水湖泊存在磷浓度较大波动的自然属性，在水环境保护目标考核中应充分考虑其不确定性，制定切实可行的控制目标；在控制策略上应将外源负荷控制放在首位，在流域污水处理厂深度除磷及流域土地利用调整等方面采取措施，实现入湖磷负荷的大幅削减，同时实施湖体生态修复与食物链调控措施，才能逐步实现湖泊水体磷浓度的控制目标. |
| 关键词: 浅水湖泊 磷 蓝藻水华 底泥再悬浮 长期观测 太湖 |
| DOI：10.18307/2021.0401 |
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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）和国家自然科学基金项目（41830757，41621002）联合资助. |
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| Fluctuation of phosphorus concentration in Lake Taihu in the past 70 years and future control strategy |
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Zhu Guangwei1, Qin Boqiang1, Zhang Yunlin1, Li Yuan2, Zhu Mengyuan1, Xu Hai1, Zhang Yibo1
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1.Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.School of Tourism and Urban & Rural Planning, Zhejiang Gongshang University, Hangzhou 310018, P. R. China
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| Abstract: |
| Understanding the changing mechanism of phosphorus concentration in lakes is the precondition of strategic decision for lake restoration. Based on the 70 years (1949-2020) phosphorus concentration monitoring data at Lake Taihu, a large shallow lake, it is found that the phosphorus concentration was highly fluctuated temporally and spatially, owing to both human pollution and natural limnological changes. Phosphorus concentrations was largely different both in the relatively clean 1950 and in the relatively polluted recent 30 years. Heavy rain storm discharge plenty of external phosphorus into the lake, causing large spatial difference of water phosphorus concentration. Strong wind causing lots of phosphorus released from lake sediment, causing large temporal fluctuation of phosphorus concentration. And algal bloom materials re- distribution by wind driving also bring about large uncertainty of phosphorus concentrations. In the recent 20 years, pollution abatement projects have significantly changed the spatial-temporal change of phosphorus concentration in Lake Taihu. Zero Action of water pollution control in Taihu catchment since 1998, water resource diversion engineering since 2007, and the bloom situation aggravate since 2017 have significantly influenced the fluctuation intensity, spatial distribution and mean value of phosphorus in Lake Taihu. However, phosphorus concentrations in the whole Lake Taihu still keep high level even plenty of pollution treatment investigation. Its reasons are owing to both external loading factors, such as largely increase of construction land use ratios, population increases, and crop planting structure change in farmlands, and internal loading factors, such as submerged vegetation degradations, hydrological structure changes, and algal bloom aggravates under climatic change. The seventy years variation characteristic of phosphorus concentration in Lake Taihu should provide lessons for large shallow lakes management. Relatively large fluctuation of phosphorus concentration in lake water is the nature of large shallow lakes. Decision-maker should consider the natural characteristic when they formulate the protection target of large shallow lakes. External loading abatement should give priority, such as land use adjustment in Lake Taihu basin and deeply phosphorus removal in tail-water of urban sewage treatment plants. At the same time, internal loading control measures, such as submerged vegetation restoration and top-down food-web control of algal biomass by bio-manipulation of fishery should be undertaken to make sure the highly fluctuation of phosphorus being largely controlled. |
| Key words: Shallow lake phosphorus cyanobacterial bloom sediment resuspension long-term observatory Lake Taihu |
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