天鹅洲长江段浮游植物群落季节演替及环境因子研究

STUDY ON PHYTOPLANKTON COMMUNITY STRUCTURE AND ITS RELATIONSHIP WITH ENVIRONMENTAL FACTORS IN TIAN'E SECTION,CHANGJIANG RIVER

通过研究长江天鹅洲白鱀豚国家级自然保护区长江段浮游动植物群落组成及其与环境因子之间的关系,揭示长江干流浮游植物群落的结构特征,以期为该区域生态系统保护与研究工作提供基础资料和科学依据。2014—2015年按季节分四次在干流沿途设置的10个采样点开展了浮游植物调查,并同步开展水温、溶解氧、总磷等水质因子监测,并采用典范对应分析(canonical correspondence analysis,CCA)研究了不同季节浮游植物群落结构变化及其与环境因子的关系。结果表明:浮游植物种类以硅藻、绿藻和蓝藻为主;全年来看生物量组成主要是硅藻和隐藻,不过春秋季时蓝绿藻密度组成占优。CCA分析则进一步显示浮游植物群落组成四季变化明显,其中磷酸盐、溶解氧和氧化还原位等水质因子对春季浮游植物群落结构存在显著的影响,但是夏冬季的浮游植物群落变化则可能是水文情势等条件起到了重要作用。

The phytoplankton community structure and its relationship with the environmental factors was studied in four seasons in the Tian＇e（Swan） Section, a part of the nature reserve for white dolphin, in the middle reach of Changjiang（Yangtze） River, to reveal the community characteristics of phytoplankton and further provide data for ecological protection and research in the area. From 2014 to 2015, an investigation was quarterly carried out in 10 sampling sites along the section and water quality factors such as water temperature, dissolved oxygen and total phosphorus were synchronously measured. Canonical correspondence analysis（CCA） was applied to analyze the phytoplankton community structure and its relationship with the environmental factors in the four seasons. The results show that the main species of phytoplankton were diatoms, chlorophytes and cyanobacteria; the diatoms and cryptophytes were dominant in the biomass composition in the whole year, but the chlorophytes and cyanobacteria were dominant in the density composition in spring and autumn. CCA analysis further indicated that the total phosphorus, dissolved oxygen and oxidation reduction potential（ORP） significantly affected the phytoplankton community structure in spring, while the hydrological factors could play a more important role in summer and winter.