于2015年8月至2016年6月对迪沟采煤沉陷湖泊浮游植物进行采样调查,共鉴定出浮游植物8门10纲17目32科62属155种,其中绿藻门、硅藻门和蓝藻门种类总和占各时期浮游植物种类总数比例超过75%.调查期间主要优势种为小席藻(Phormidium tenu)、两栖颤藻(Oscillatoria amphibia)、肘状针杆藻(Synedra ulna)和尖尾蓝隐藻(Chroomonas acuta)等.浮游植物密度和生物量的变化范围分别是22.68×105~290.24×105cells/L和2.47~7.41 mg/L.浮游植物细胞密度的时间变化显著(F=15.48,P<0.05),其总体趋势为先降后升,生物量变化趋势与密度变化相似,蓝藻的细胞密度和生物量大多数时期占优势.Shannon-Wiener多样性指数(H′)呈现显著的空间差异,水系沟通提高了沉陷湖泊浮游植物多样性.冗余分析(RDA)表明,水温、透明度、总磷和硝酸盐氮是影响浮游植物群落结构的主要环境因子,水温是影响浮游植物时间变化的关键因子.迪沟采煤沉陷湖泊的水体呈现富营养状态,浮游植物群落结构有明显的富营养化特征,沉陷湖泊存在潜在的蓝藻水华风险.%In order to study space-time variation of phytoplankton and its relationship with water environmental factors in Digou coal mining subsidence lake,the phytoplankton community was investigated from August 2015 to June 2016. Results showed that a total of 155 species of phytoplankton were identified,which belong to 8 phyla,10 classes,17 orders,32 families and 62 genera. The species number of Chlorophyta,Bacillariophyta and Cyanophyta accounted for more than 75% of phytoplankton species. During the investiga-tion,the main dominant species were Phormidium tenu,Oscillatoria acutissima,Synedra ulna,Chroomonas acuta,etc. The variation range of the density and biomass of phytoplankton respectively was 22.68×105-290.24 ×105cells/L and 2.47 -7.41 mg/L. The density of phytoplankton changed significantly (F=15.48,P<0.05),and the overall trend was to rise after the first drop. Biomass exhibited a similar temporal behavior to that seen in the density. The density and biomass of Cyanobacteria were dominant in most of the time. The spatial differences of Shannon-Wiener index(H′) were obvious,and water system communication improved phytoplank-ton diversity in subsidence lake. Redundancy analysis (RDA) indicated that water temperature, transparency, total phosphorous and nitrate nitrogen were important factors affecting the variations of phytoplankton community in the subsidence lake, and water tempera-ture was the key factor affecting the temporal variation of phytoplankton. Digou mining subsidence lake was eutrophic,and the eutroph-ic characteristion of phytoplankton community was obvious. Meanwhile,the lake had a potential risk of blue algae bloom.
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