Abstract:

Eutrophication has been one of threats to the aquatic environment nowadays. Learning the water quality and analyzing the possibility of eutrophication of Weiming Lake, an irreplaceable symbol of Peking University, is the scientific basis to improve the water quality and a reference to the protection of other artificial lakes. Hardly disturbed by anthropogenic activities, the water quality of Weiming Lake was good in nitrogen related indexes, but the indexes of COD, TP, and DO were at or even worse than Level V water quality in all the regions and seasons. The average TLI indexes of Weiming Lake was 56.1, slightly eutrophication. PCR-DGGE analysis showed the diversity of sediment bacterial community varied through seasons, higher in spring and summer, highly related with the location and the weight of nutrients in summer and autumn. Linear regression showed that the activities of algae may influence the sediment bacterial community through nitrogen fixation.

Key words: Weiming Lake, water quality, eutrophication, sediment bacterial community, PCR-DGGE

摘要：

通过测定不同季节北京大学未名湖不同区域的水质指标, 发现在无显著人为外源影响的条件下, 水体氮相关指标较好, 四季全部采样点的氨氮都优于Ⅱ类水指标, 总氮都优于Ⅳ类水指标, 但COD, TP和DO等指标在有的采样点仅达到、甚至劣于Ⅴ类。未名湖的平均综合营养状态指数(TLI)为56.1, 属于轻度富营养化。利用PCR-DGGE分析未名湖的底泥微生物群落, 结果表明其多样性随季节变化较明显, 春、秋季多样性指数都较高, 夏、秋季多样性指数与地理位置及水体营养盐含量呈显著正相关关系。线性回归结果提示未名湖底泥微生物群落可能受藻类固氮作用的影响。

关键词: 未名湖, 水质, 富营养化, 底泥微生物群落, PCR-DGGE