大冶市城市湖泊夏季浮游植物群落结构及其影响因子

Summer phytoplankton community structure in urban lakes of Daye City and its influencing factors

针对大冶市城市湖泊水体富营养化问题,为掌握其水体浮游植物群落特征,对大冶市尹家湖、红星湖和三里七湖的夏季浮游植物进行了野外调查和室内研究,并运用冗余分析(RDA)和相关性分析等多种方法探究其与环境因子的关系,以期为湖泊生态修复提供参考。结果表明:三个湖泊发现浮游植物合计8门116种。运用优势度指数(Y)分析得出,尹家湖夏季浮游植物优势种主要有假鱼腥藻(Pseudanabaena limnetica)、细小平裂藻(Merismopedia tenuissima)和泽丝藻(Limnothrix redekei),红星湖的优势种主要有钝顶螺旋藻(Spirulina platensis)和卷曲鱼腥藻(Anabaena circinalis),三里七湖的优势种主要有巨颤藻(Oscillatoria princeps)、啮蚀隐藻(Cryptomonas erosa)和肘状针杆藻(Synedra ulna);平均丰度表现为红星湖>三里七湖>尹家湖,浮游植物平均生物量分别为201.84μg/L、366.88μg/L和28.35μg/L。综合营养状态指数(TLI)评价表明,尹家湖、红星湖和三里七湖水体分别为轻度富营养、重度富营养和中度富营养状态,而利用浮游植物Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J)和Margalef丰富度指数(D)计算得出三个湖泊水质均为中度污染水平。冗余分析(RDA)表明,影响该三湖夏季浮游植物群落结构的主要环境因子分别是总氮和总磷、水温和总磷、高锰酸盐指数和水温。

Aiming at the problem of water body eutrophication in the urban lakes of Daye City, the relevant field investigations and indoor studies on the summer phytoplanktons within Yinjiahu Lake, Hongxinghu Lake and Sanliqihu Lake are carried for making clear the characteristics of the summer phytoplankton communities in the water bodies therein, while their relationships with environmental factors are explored with several methods, i.e. redundancy analysis(RDA), correlation analysis, etc., so as to provide some references for the ecological restoration of the lakes. The results show that a total of 116 species of phytoplankton in 8 phyla are found in the three lakes. Through the analysis of the dominance index(Y), it is obtained that the dominant species of the summer phytoplankton in Yinjia Lake are Pseudanabaena limnetica, Merismopedia tenuissima and Limnothrix redekei and the dominant species in Hongxing Lake are Spirulina platensis and Anabaena circinalis, while the dominant species in Sanliqi Lank are Oscillatoria princeps, Cryptomonas erosa and Synedra ulna. For which the mean phytoplankton abundances of the three lakes are Hongxing Lake>Sanliqi Lake>Yinjia Lake with the mean phytoplankton biomasses are 201.84 μg/L, 366.88 μg/L, and 28.35 μg/L respectively. The relevant evaluation made on the comprehensive trophic level index shows that the water bodies of Yinjia Lake, Sanliqi Lake and Hongxing Lake are in the mild eutrophication, severe eutrophication and moderate eutrophication status respectively, while the water qualities of the three lakes calculated by means of Shannon-Wiener diversity index(H′), Pielou evenness index(J), and Margalef richness index(D) are all on the moderate pollution level. The related redundancy analysis(RDA) indicates that the main environmental factors affecting the structure of the summer phytoplankton communities in the three lakes are total nitrogen and total phosphorus, water temperature and total phosphorus, permanganate index and water temperature respectively.