西河湾浮游植物调查及营养状况评价

Phytoplankton investigation and tropical status evaluation in Xihe lake

对西河湾2019年3~11月的水体理化指标和浮游植物群落结构进行调查,监测结果表明,西河湾水质状况为V类水标准,主要超标项目为总磷、总氮.各采样点的综合营养状态指数在43.9~49.6之间波动,西河湾整体达到中营养化水平.调查期间共发现浮游植物8门58属116种,其中绿藻门和硅藻门在种类上占据优势,分别占藻类种类数的41.38%和31.03%.各采样点藻细胞密度变化范围较大,全年波动于0.35×10^5~180.6×10^5ind/L之间,平均为19.7×10^5ind/L.Margalef丰富度指数、Shannon-Wiener多样性指数、均匀度指数随时间呈现出一定的变化,西河湾水体的污染程度3月、9月高于5月、7月、11月.3种多样性指数对西河湾水质评价结果一致,显示该水体几乎全年处于中污型状态,与综合营养状态指数分析结果也具有较好的一致性.

The phytoplankton community and water quality of Xihe lake was investigated from March to November 2019.The result showed that the water qulity is class V of the national water qulity standard and the main over-standard items were total phosphorus(TP)and total nitrogen(TN).The values of TLI was 43.9~49.6,which belonged to the medium nutritional level.A total of 116 species from 8 phyla of phytoplankton were detected.The dominant algae were Chlorophyta and Bacillariophyta with a ratio of 41.38%and 31.03%.The density of phytoplankton had a wide range between 0.35×10^5ind/L^180.6×10^5ind/L and the average was19.7×10^5ind/L.The Margalef index and the Shannon-Wiener index and the Pielou’s uniformity index changed with time.The degree of pollution in March and September was higher than May,July and November.The results of tropical status evaluation of the three biotic diversity index were in accordance with the water qulity evaluation,which showed that the Xihe Lake was in the middling mesotrophication,and the value of TLI were relatively consistent.