【摘要】 为了解星云湖浮游植物群落结构,于2017年1月(冬季)、4月(春季)、7月(夏季)和10月(秋季)对星云湖12个点位浮游植物进行了采样调查。基于藻类密度、优势度和多样性指数对浮游植物群落结构特征及水体营养状态进行了分析评价。结果表明,星云湖共有浮游植物6门50属,其中绿藻在种类组成上占绝对优势。4个季节蓝藻密度占藻类总密度的94. 87%～99. 48%,微囊藻属为单一优势类群,优势度为0. 930～0. 991。浮游植物密度夏秋季最高,分别达45 966. 94×104cells/L和46 149. 44×104cells/L;春季次之,为23 956. 63×104cells/L;冬季最低,为11 296. 26×104cells/L。空间分布上,冬夏季北区密度高于南区,春季南区高于北区,秋季南北区无明显差异。Shannon-Wiener多样性指数(H’)为0. 04～0. 86,平均值0. 31; Pielou均匀度指数(J)为0. 01～0. 22,平均值0. 08; Margalef物种丰富度指数(D)为0. 60～1. 31,平均值1. 02。生物评价认为,星云湖水体营养状态为富营养化类型。总之,星云湖4季浮游植物密度较高,且其时空分布差异明显;微囊藻优势化程度较高,多样性水平较低,浮游植物群落结构简单,水体富营养化程度严重。更多还原

【Abstract】 The present paper is aimed to introduce our investigation results of the spatial and temporal structural features of the phytoplankton community in Xingyun Lake,which can be expected to provide a database for its water ecosystem exploitation and protection. For our research purpose,we have collected the seasonal phytoplankton samples from the 12 sites of the lake area in January,April,July and October,2017,respectively. And,then,we have also made our analysis of the identification and examination of the phytoplankton cell densities and species via the light microscope( Leica DM2500). Furthermore,based on the observation and examination of the algal biological indices of the phytoplankton density,the dominance and diversity indices,and the phytoplankton community structure features,we have made an analysis and evaluation of the trophic state of the lake water.Our analysis and evaluation intend to help to achieve the following results:( 1) We have found a total number of 50 phytoplankton genera belonging to the 6 phyla,of which the most abundant group should be that of Chlorophyta( consisting of 26 genera),and,then,Cyanophyta( consisting of 11 genera),Bacillariophyta( consisting of 7 genera),Cryptophyta( of 2 genera),Pyr-rophyta( of 2 genera),Euglenophyta( of 2 genera). And,( 2),in terms of the quantitative composition,it has been found that Cyanophyta density may take up a proportional ratio of94. 87%-99. 48% of the total density duirng the 4 seasons of a year,whereas Microcystis tends to be the unique dominant species,with its dominant proportional rate of 0. 930-0. 991;( 3)The cell density of phytoplankton used to be varying seasonally,with its highest density rate coming up in summer( 45 966. 94 ×104 cells/L) and autumn( 46 149. 44 × 104 cells/L),and,then,followed by spring( 23 956. 63 × 104 cells/L) with its lowest density coming up in winter( 11 296. 26 × 104 cells/L). As to its spatial distribution,we have also discovered that there doesn’t seem to be any significant difference between the northern part and the southern part of the lake in autumn with the average density of phytoplankton being higher in the northern part than that in the southern one in winter and summer,though it may be opposite in spring.( 4) The indices of Shannon-Wiener diversity,Pielou Evenness and Margalef have been indicaded as 0. 04-0. 86( average in 0. 31),0. 01-0. 22( average in 0. 08) and 0. 60-1. 31( average in 1. 02),respectively;( 5) From the evaluation in view of biological study by Shannon-Wiener diversity index,Pielou Evenness index,Margalef index and phytoplankton density,it can be found that the water trophic state is of eutrophic type in Xingyun Lake. The above results show that,the phytoplankton density tends to be higher and its spatial and temporal distributions tend to be remarkably different for the four seasons in a year in Xingyun Lake. And,therefore,higher dominance of Microcystis and lower diversity of phytoplankton can therefore lead to the simplicit phytoplankton community and serious eutrophication in the lake.更多还原