| 引用本文: | 朱伟,胡思远,冯甘雨,章元明,翟淑华,薛宗璞,赵帅,陈怀民,王若辰.特大洪水对浅水湖泊磷的影响:以2016年太湖为例.湖泊科学,2020,32(2):325-336. DOI:10.18307/2020.0201 |
| ZHU Wei,HU Siyuan,FENG Ganyu,ZHANG Yuanming,ZHAI Shuhua,XUE Zongpu,ZHAO Shuai,CHEN Huaimin,WANG Ruochen.Effects of great floods on phosphorus in shallow lakes: A case study of Lake Taihu in 2016. J. Lake Sci.2020,32(2):325-336. DOI:10.18307/2020.0201 |
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| 特大洪水对浅水湖泊磷的影响:以2016年太湖为例 |
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朱伟1, 胡思远1, 冯甘雨1, 章元明2, 翟淑华2, 薛宗璞1, 赵帅1, 陈怀民1, 王若辰1
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1.河海大学环境学院, 南京 210098;2.太湖流域水资源保护局, 上海 200434
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| 摘要: |
| 2016年太湖发生特大洪水，水位达到历史第二，入湖水量比平均年多60.8亿m3.而从2016年开始太湖磷指标改变了2010年以来平缓下降的趋势出现回升，也就是出现所谓“磷反弹”的问题.为了研究磷反弹和特大洪水之间的关系，本研究从2016年入湖水量、水质、磷通量、水中磷存量以及磷在太湖中的迁移过程出发，对大洪水前后太湖磷的变化进行分析.结果表明：洪水期间入湖河道带来大量的磷是引起磷反弹的主要原因.由于洪水的影响，2016年磷净入湖通量比往年平均水平多出579.2 t，约达到1683.0 t.其中，两次洪水贡献极大，约占全年水平的50%（6-7月和10月的洪水分别带入580.5和268.2 t磷）.磷反弹的另一个原因在于太湖存在较高的磷滞留率，磷在入湖后很难经由出湖河道排出.从入湖后磷的归趋上看，洪水过程中高磷浓度水块尽管存在由太湖西北部向东、南部迁移的过程，但途中水体磷浓度出现显著降低（即滞留现象），导致高磷浓度水块未能到达出湖排泄区（太浦港、望虞河等）.全年净入湖磷通量中仅有小部分（205.3 t）直接引起水体磷浓度上升，而其余的大部分则滞留于底泥之中，明显高于往年水平.2016年滞留在太湖内的磷很可能破坏了往年底泥-上覆水的磷平衡，对后续水质的变化产生间接的影响. |
| 关键词: 太湖 磷反弹 洪水 通量 存量 磷迁移 |
| DOI：10.18307/2020.0201 |
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| 基金项目:江苏省科技计划项目（BE2018737）、国家水体污染控制与治理科技重大专项（2017ZX07603-003-04）和中央高校建设世界一流大学（学科）和特色发展引导专项资金项目联合资助. |
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| Effects of great floods on phosphorus in shallow lakes: A case study of Lake Taihu in 2016 |
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ZHU Wei1, HU Siyuan1, FENG Ganyu1, ZHANG Yuanming2, ZHAI Shuhua2, XUE Zongpu1, ZHAO Shuai1, CHEN Huaimin1, WANG Ruochen1
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1.College of Environment, Hohai University, Nanjing 210098, P. R. China;2.Taihu Basin Water Resources Protection Bureau, Shanghai 200434, P. R. China
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| Abstract: |
| In 2016, a heavy flood occurred and resulted the second highest water level of Lake Taihu in the history. The volume of water into Lake Taihu was 5.79×109 m3 more than the average of previous years. Since then, the phosphorus index of Lake Taihu changed from a slow decline since 2010, to the so-called "phosphorus rebound". In order to study the relationship between phosphorus rebound and the great flood of 2016, this study analyzed the water volume, water quality, phosphorus flux, phosphorus storage in water and phosphorus migration in Lake Taihu. The change of phosphorus before and after the great flood was also carried out. The results showed that the large amount of phosphorus in the river channel during the flood period is the main cause of phosphorus rebound. Due to the impact of flooding, the net flux of phosphate into the lake in 2016 was 579.2 t more than the previous years' average, reaching 1683.0 t. Among them, the two floods contributed a great share, accounting for about 50% of the annual level (the floods from June to July and October brought 580.5 and 268.2 t of phosphorus, respectively). Another reason for the rebound of phosphorus is that there is a high phosphorus retention rate in Lake Taihu, and it is difficult for phosphorus to be discharged through the lake channel after entering the lake. From the fate of phosphorus after entering the lake, the water block with high-phosphorus concentration in the flood process, although there is a migration from the northwestern to the east and the south in Lake Taihu, the phosphorus concentration in the water body is significantly reduced (i.e., the retention phenomenon), resulting in high phosphorus concentration. The water block failed to reach the lake discharge area (Taipu Port, Wangyu River, etc.). Only a small part (205.3 t) of the net phosphorus flux in the whole year directly caused a rise of the phosphorus concentration in the water body, while the rest was retained in the sediment, which was significantly higher than the previous years. Phosphorus retained in Lake Taihu in 2016 is likely to destroy the phosphorus balance of the mud-overlying water at the end of the year, which has an indirect impact on subsequent changes in water quality. |
| Key words: Lake Taihu phosphorus rebound flood flux stock phosphorus migration |
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