太湖流域主要河道浮游植物类群对比研究

Comparison of the Phytoplankton Community in Major Rivers of the Taihu Basin

2010年春季(4月13日-4月22日)和夏季(7月10日-7月19日)对太湖流域主要入湖河道进行了两次调查。对不同河道浮游植物群落结构进行了对比分析。入湖河流优势属主要有针杆藻(Synedra sp.)、隐藻(Cryptomonas sp.)、直链硅藻(Aulacoseira sp.)、脆杆藻属(Fragilaria sp.)和舟形藻(Navicula sp.)等;出湖河道主要优势属有直链硅藻(Aulacoseira sp.)、栅藻(Scenedesmus sp.)、隐藻(Cryptomonas sp.)等。夏季入湖河道优势属有针杆藻(Synedra sp.)、十字藻(Crucigenia sp.)、隐藻(Cryptomonas sp.)、裸藻(Euglena sp.)和微囊藻(Microcystis sp.)等;出湖河道优势属有直链硅藻(Aulacoseira sp.)、栅藻(Scenedesmus sp.)、隐藻(Cryptomonas sp.)、针杆藻(Synedra sp.)等。太湖流域河道浮游植物物种多样性春季要高于夏季,电导率、总磷、总氮、总悬浮物浓度、高锰酸钾指数和硝态氮与河道内浮游植物物种多样性显著相关。典范对应分析(CCA)结果显示影响春季浮游植物群落结构的关键因子有总悬浮物浓度、总氮和电导率,夏季则主要是高锰酸钾指数、硝态氮和总氮浓度。

Phytoplankton assemblages were sampled in spring（13th-22nd April） and summer（10th-19th July）,2010,and were compared in order to obtain basic information of the community of phytoplankton and their relationships with environmental factors among different rivers in the Taihu basin.Samples for phytoplankton were both identified and counted under a microscope at 400×.The results of counting shown that Synedra sp.,Cryptomonas sp.,Aulacoseira sp.,Fragilaria sp.and Navicula sp.were the dominant genus in the inflowing rivers and Aulacoseira sp.,Scenedesmu sp.,Cryptomonas sp.,Asterionella sp.and Closterium sp.in outflowing rivers in spring.And in summer,the major genus in inflowing rivers were Synedra sp.,Crucigenia sp.,Cryptomonas sp.,Euglena and Microcystis sp.and were Aulacoseira sp.,Scenedesmus sp.,Cryptomonas sp.,Synedra sp.in outflowing rivers.That is to say the phytoplankton community is different between both in temporal and spatial distribution in Taihu basin.Then several diversity indices were calculated and the indices shown that diversity of phytoplankton in spring were slightly higher than in summer,and it was also varied among rivers.Liner regressions between diversity indices and environmental factors indicated that Shannon-Wiener diversity index had strong relationships with conductivity,total phosphorus（TP）,total nitrogen（TN）,total solid suspended（SS）,chemical oxygen demand（CODMn） and nitrate（NO3--N） in spring and nitrate（NO3--N）,chemical oxygen demand（CODMn） conductivity in summer.Further more,the most important environmental factors that regulated the phytoplankton community（basically analyzed according to predominated genus） were SS,TN,and conductivity in spring,and were CODMn,NO3--N and TN in summer as illuminated by the ordination of Canonical correspondence analysis（CCA）.