Ecological restoration of urban eutrophic lakes-a case study on the physical and ecological engineering in Lake Mochou, Nanjing

为了探索城市富营养化湖泊生态修复技术,2000年9月在南京市莫愁湖物理生态工程试验区内,开展了隔离外源污染、覆盖底泥和种植水生植物对湖泊水质平均水平和水体脉动强度影响的比较研究.试验结果表明,通过围隔隔离外源污染可在较短时间内迅速改善湖泊TN的平均水平,但难以提高湖泊生态系统的稳定性;通过覆盖底泥控制内源污染难以改善湖泊水质的平均水平,并且难以提高湖泊生态系统的稳定程度;种植水生植物不仅能够全面改善湖泊水质的平均水平,而且可以提高湖泊生态系统的稳定性.此外,富营养化湖泊中,藻类生长与湖水营养盐浓度并不存在正相关的关系.因此,对城市湖泊富营养化的防治,在控制外源污染降低营养盐浓度的同时,应恢复湖泊原有的以水生高等植物为主的生态系统.;To study the technologies of ecological restoration for urban eutrophic lakes, the comparative experiments of different influence for external pollution isolating，sediment covering and macrophytes planting to the average level of water quality and the fluctuating intensity of water body were carried out in Lake Mochou of Nanjing in September 2000. The results showed that it can improve the average level of TN in a relatively short period but it is different to increase the stability of the lake ecosystem through isolating the external pollution by the soft wall； it cannot improve the average level of the water quality or increase the stability of the lake ecosystem either through isolating the internal pollution by covering the sediment； it can not only improve the average level of the water quality comprehensively, but also increase the stability of the lake ecosystem through macrophyte restoration. Further more, algae growth is not positively correlated with nutrient concentration in eutrophic lakes. In a word, to control the eutrophication of urban lakes, it should be done to restore the pristine ecosystem with macrophytes restoration associated with the priority of external pollution controlling.