苏皖交界河网区浮游植物群落结构及其与环境因子关系的研究

苏皖交界处的石臼湖是长江下游唯一的通江淡水湖,通过青弋江和姑溪河直接与长江相连,形成了复杂的河网水系。为探讨这种复杂的河网水系中浮游植物种群结构特征,2012年平水期和枯水期分别对石臼湖及其周边入湖支流进行了浮游植物调查,研究河网水系中河网与湖区浮游植物的种类组成、季节变化及与环境因子的关系。结果显示:共采集到浮游植物105种,平水期与枯水期种类数差别不大,两次调查均出现的种类约有70%相同;浮游植物丰度最高可达1×108cell/L,达到了水华暴发的标准。优势种类主要绿藻门和蓝藻门为主,但是从生物量来看硅藻门占优。排序分析显示河网区域浮游植物季节演替明显,且河网与湖区浮游植物群落结构差异明显,进一步分析则表明影响浮游植物主要的环境因子是氮、磷等营养元素。

STUDY ON PHYTOPLANKTON COMMUNITY AND ITS RELATIONS TO THE ENVIRONMENTAL FACTORS IN THE QINGYI/GUXI RIVER NETWORK

Shijiu Lake is the sole freshwater lake connected to the Yangtze River through the Qingyi River and the Guxi River,forming a complex drainage network.To explore the phytoplankton community structure in this complex river network,an investigation was carried out in the normal season and the dry seasons in 2012 on the phytoplankton in Shijiu lake and its surrounding tributaries.In this investigation,the species composition,seasonal variation and its relationship with environmental factors was analyzed.The results showed that a total of 105 species of phytoplankton were collected.There was no obvious difference in the number of species between the normal season and the dry season,with 70％ species shared;the abundance of phytoplankton was at most 1 × 108 cell / L,reaching the standards of the water bloom.The dominant taxa were chlorophyta and cyanobacteria,but the diatom is dominant in biomass.The direct ordination analysis furtherly showed the seasonal succession of phytoplankton was obvious in the river network and the lake area,and the main environmental factors affecting phytoplankton were the nutrients including the nitrogen and phosphorus.