白洋淀轮虫群落结构及富营养化评价

Species diversity of rotifer and the trophic state of Baiyangdian Lake

于2018年5月(春)、8月(夏)和10月(秋)对白洋淀26个采样点轮虫物种组成和群落结构进行了系统调查,测定了水温(WT)、溶解氧(DO)、pH值、水深(WD)、透明度(Tr)、总氮(TN)、总磷(TP)、叶绿素a(Chla)等环境因子,分析了轮虫群落参数与环境因子的关系,综合评价了白洋淀水体富营养化程度.共鉴定出轮虫21属61种,以耐污性种类为主,角突臂尾轮虫、萼花臂尾轮虫和小多肢轮虫为优势种.各采样点轮虫种数差异较大,最多为20种(聚龙淀),最少仅为6种(大麦淀).轮虫平均丰度和生物量呈现明显的季节变化,秋季最高(3372 ind./L,0.90 mg/L),夏季其次(1240 ind./L,0.88 mg/L),春季最低(210 ind./L,0.22 mg/L);轮虫最高丰度为6930 ind./L(三角淀,秋季),最低仅为2 ind./L(平阳淀,夏季).Shannon-Wiener多样性指数(H′)和Pielou均匀度指数(J)夏季最高(分别为2.30和0.86).经相关性分析发现,轮虫丰度与DO、WD、Chla、TP呈显著正相关,而与Tr显著负相关;轮虫种数与WD显著正相关,与WT显著负相关.与历史资料相比,白洋淀水质在一定程度有所好转,但仍处于富营养化状态.

In May(spring),August(summer)and October(autumn)of 2018,the rotifer diversity,community structure and the environmental factors,namely water temperature(WT),dissolved oxygen(DO),pH,water depth(WD),water transparency(Tr),total nitrogen(TN),total phosphorus(TP)and chlorophyll-a(Chla)at 26 sampling sites in Baiyangdian Lake were investigated.The relationship between the rotifer community parameters and environmental factors was analyzed,and the eutrophication degree of Baiyangdian Lake was also evaluated.A total of 61 rotifer species were identified in this survey,Brachionus calyciflorus,B.angularis and Polyarthra minor were the main dominant species throughout the year.The distribution of rotifer species at each sampling site is significantly different,with a maximum of 20 species(Julongdian)and a minimum of only 6 species(Damaidian).The average abundance and biomass of rotifers showed obvious seasonal changes,the highest in autumn(3372 ind./L,0.90 mg/L),the second in summer(1240 ind./L,0.88 mg/L),and the lowest in spring(210 ind./L,0.22 mg/L),the highest abundance was 6930 ind./L(Sanjiaodian,autumn),and the lowest was only 2 ind./L(Pingyangdian,summer).The Shannon-Wiener diversity index(H′)and evenness index(J)have the highest average values in summer,Which were 2.30 and 0.86,respectively.Correlation analysis showed that rotifer abundance was significantly positively correlated with DO,WD,Chla,and TP,and significantly negatively correlated with Tr;the number of rotifer species was significantly positively correlated with WD,and significantly negatively correlated with WT.Comparing with previous data,the water quality of Baiyangdian Lake is better but still in a state of eutrophication.