北京野鸭湖浮游植物群落结构与水质关系研究

Relationship between Community Structure of Phytoplankon and Water Quality in Yeyahu Lake,Beijing

2011年4～11月,调查北京野鸭湖4个采样区6个采样点浮游植物的种类组成,计算其密度和生物多样性指数,分析浮游植物群落指标与水质理化参数的关系,利用修正卡尔森指数及群落多样性指数等进行了水质综合评价。结果表明,2011年4～11月,4个采样区共发现8门116种藻类,其中绿藻门、硅藻门和裸藻门占76.72%。浮游植物的群落结构、密度和多样性指数季节变化较大。在夏、秋季水温较高时,浮游植物种类较丰富,其中,以绿藻门(40.73%)最多,其次为硅藻门(26.96%)和蓝藻门(17.56%)。春季和冬季水温较低,浮游植物种类比较少,但仍然是绿藻门和硅藻门植物占主导。各采样区的浮游植物细胞密度之和,在6月达到最大值,为36119.9×104cells/L,最低值出现在11月,为5209.75×104cells/L。浮游植物细胞密度在夏季和秋季较大,与浮游植物种类组成的季节变化具有一致性,即随着水温的升高和水中营养盐的增加,浮游植物的种类和细胞密度都在增加,且都是蓝藻占绝对优势,其次为绿藻。Ⅰ区～Ⅳ区浮游植物的年平均细胞密度分别为4881.36×104cells/L、1015.22×104cells/L、4875×104cells/L和2466×104cells/L,其中,绿藻门和蓝藻门植物细胞密度占浮游植物总细胞密度的99.81%,优势种为小颤藻(Oscillatoria tenuis)、大螺旋藻(Spirulina major)、微小色球藻(Chroococcus minutus)和蓝纤维藻(Dactylococcopsis acicularis)。野鸭湖浮游植物的Shannon-Wiener指数、Pielou均匀度指数变化规律一致。野鸭湖春季和冬季水质相对较好,夏季和秋季水质相对较差。Shannon-Wiener指数和Pielou均匀度指数呈显著正相关(p<0.01),说明野鸭湖浮游植物物种多样性指数的变化,很可能是由于浮游植物群落均匀度的变化而不是由于其种类数的变化。野鸭湖浮游植物的生物多样性较高。4个采样区的多样性指数及均匀度指数之间没有明显差异。野鸭湖已经被污染,其水体为富营养型。水温和总氮含量是影响野鸭湖浮游植物群落结构的主要因素。

Studies on community structures of phytoplankon,including species richness,density and biodiversity indices,and correlation analysis between community index of phytoplankton and water quality parameters were carried out from April to November of 2011 in 6 sampling points of 4 sampling areas in Yeyahu Lake,Beijing.Water quality of Yeyahu Lake was also assessed by fixed Carlson index and biodiversity indices.The results showed that 116 species of algae were found from April to November,of which 76.72% were Chlorophyta,Bacillariophyta and Euglenophyta.There was great seasonal variation in phytoplankton assemblage composition,cell density and biodiversity index.In summer and autumn,the water temperature was higher than spring and winter,the phytoplankton species was richer.Chlorophyta and Bacillariophyta were dominant and each composed of 40.73% and 26.96% of the phytoplankton species,followed by Cyanophyta,which composed of 17.56%.In spring and winter,the water temperature was low,only relatively few species of phytoplankton were found.Chlorophyta and Bacillariophyta were also dominant.The sum of Phytoplankton cell density in each sampling plot reached a peak value in June.While the lowest in November.Respectively were 36 119.9×10 4 cells/L and 5 209.75×10 4 cells/L.Phytoplankton density was maximum in summer and fall,so as the seasonal variation of phytoplankton species composition.As the increasing temperature and nutrients,the specie abuandance and density were increasing;Cyanobacteria was dominant in all year,followed by Chlorophyta.The annual mean cell densities of algae fromⅠpart to Ⅳ part were 4 881.36×10 4 cells/L,1 015.22× 10 4 cells/L,4 875.00×10 4 cells/L,2 466.00×10 4 cells/L,respectively,of which 99.83% were Chlorophyta and Cyanophyta,the Oscillatoria tenuis,Spirulina major,Chroococcus minutus and Dactylococcopsis acicularis were dominated in the algae community from April to November.Seasonal variability was the same for the indices of Shannon-Wiener index and Pielou index.And they were higher in May,November,but lower in June,October.Shannon-Wiener indexes of May and November were 2.16 and 2.09 respectively;Shannon-Wiener indexes of June and October,were 1.45 and 1.40 respectively,So the water quality in spring and winter was better;while the water quality was worse in summer and autumn.Shannon-Wiener diversity index and Pielou index were highly significant positive correlation （p0.01）.The species diversity indices of Yeyahu Lake,may be more due to community evenness changes rather than species abundance.The algae diversity indexes of species Shannon-Wiener fromⅠpart to Ⅳ part were 1.524,1.956,1.786 and 2.014,respectively.According to values of algae comprehensive index,Yeyahu Lake has suffered serious pollution and can be regarded as eutrophication status.Logarithm density of algae was positively correlated with total nitrogen content （p0.01）,and species richness was correlated with water temperature and total nitrogen content （p0.05）.Both water temperature and total nitrogen content were the major factors affecting the community structure of phytoplankton of Yeyahu Lake.