| 摘要: |
| 根据2005-2006年太湖湖泊生态系统研究站的监测结果,结合历史监测记录,评价了近5年来太湖富营养化的趋势.结果显示,从2000年以来,太湖的富营养化状况有加重趋势.主要表现在:1)与历史监测资料对比,近5年来无论梅梁湾还是湖心区,夏季水体TN、TP含量均呈增高趋势,如1992-2001年,太湖湖心区夏季(6-8月份)水体TN的平均值为1.706 mg/L (范围1.238-2.266mg/L),而2002-2006这5年间该平均值为2.344mg/L(范围1.924-2.717mg/L),明显高于前10年(p=0.005),另外,同期湖心区夏季的水体透明度则明显下降(1992-2001年夏季平均值为0.63 m,而2002-2006年则为0.34 m,p=0.003);2)从野外调查看,太湖夏季水华暴发的范围越来越大,从2000年以前的梅梁湾、竺山湾及部分湖西区为主,发展到2006年的整个西太湖,夏季暴发水华的面积占太湖总面积的一半以上,且一年中出现水华的时间越来越长,水华出现的频率越来越高,微囊藻水华为特征的藻型生态系统在大太湖似乎越来越稳定;3)近年来太湖沉水植物分布区的面积有所下降.研究表明,太湖近年来富营养化的现状不容乐观,原因可能与近几年异常的气候和水文条件有关,也可能与水草区的不断破坏而减弱了微囊藻水华的生态竞争有关,应引起有关部门重视. |
| 关键词: 太湖 富营养化 营养状态指数 微囊藻水华 长期监测 浅水湖泊 |
| DOI：10.18307/2008.0103 |
| 分类号: |
| 基金项目:中国科学院知识创新工程重要方向项目(KZCX2-YW-419);国家自然科学基金重点项目(40730529)联合资助. |
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| Eutrophic status and causing factors for a large, shallow and subtropical Lake Taihu, China |
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ZHU Guangwei
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Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China
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| Abstract: |
| As the third largest freshwater lakes of China and seriously suffered by Microcystis algal bloom in recent 20 years, LakeTaihu's eutrophic status had been analyzed based on the monthly monitoring data in recent 5 years. The analysis indicated thateutrophication of Lake Taihu became more and more serious since 2000. Comparing to the mean values in recent 5 years, the waterquality variables like total nitrogen, total phosphorus, and transparency, water quality of Lake Taihu were worse than that between1991 and 2001. The summer mean of TN between 2002 and 2006 was significantly higher than that of between 1992 and 2001 (p =0.005). And the transparency mean of summer of 2002-2006 in center of Lake Taihu was only 0.34 m, which was significantly lowerthan that of 1992-2001 with a mean 0.63 m (p = 0.003). Moreover, Microcystis blooming areas in summer increased from about onefourth of the lake before 2000 to over half of the lake in 2006. Blooming season from June to October before 2000 also extend fromMay to December in 2006. Microcystis blooms occur more and more regularly in the lake. And dominant areas of submergedmacrophytes decreased quickly. The deteriorate trend of eutrophication in Lake Taihu may partly due to the abnormal dry and hotclimate in recent 2 years. However, destroy of submerged macrophytes also possibly contributed to the fast widespread of bloom. |
| Key words: Lake Taihu eutrophication trophic state index Microcystis algae bloom long-term ecological monitoring shallow lakes |
