三峡水库上游长寿湖浮游藻类的季节变化特征及关键环境影响因子

Seasonal phytoplankton dynamics and its relationship with key environmental factors in Lake Changshou,upper reaches of the Three Gorges Reservoir

基于2013年3月-2014年2月的长寿湖浮游藻类以及水质的监测结果,分析浮游藻类物种组成、密度以及多样性指数的季节动态,利用非度量多维尺度和相似性分析检验不同季节浮游藻类群落差异,同时利用典范对应分析法确定影响不同季节浮游藻类群落结构的关键环境因子.结果表明:泽丝藻(Limnothrix sp.)、小尖头藻(Raphidiopsis sp.)、汉斯冠盘藻(Stephanodiscus hantzschii)、具尾逗隐藻(Komma caudata)、鞘丝藻(Lyngbya sp.)和马索隐藻(Cryptomonas marssonii)为长寿湖优势种群,不同季节间浮游藻类群落组成结构存在较大差异.浮游藻类群落结构以春季最为简单,夏季次之,秋、冬季最为复杂.不同季节影响浮游藻类群落结构的环境因子差异较大,水温和营养盐是影响浮游藻类群落结构最重要的环境因子,光照强度、高锰酸盐指数、氧化还原电位、溶解有机碳在秋、冬季节同样成为影响浮游藻类群落结构的关键环境因子.

An investigation was conducted on the phytoplankton community structure in the Lake Changshou in March, 2013 to February, 2014 to analyze the seasonal variation of phytoplankton composition density and diversity indices. Differences in the phy- toplankton composition among seasons were tested using the Non-metric Multidimensional Scaling and Analysis of Similarities, and environmental influencing factors of phytoplankton composition were identified using Canonical Correspondence Analysis. The results showed that Limnothrix sp., Raphidiopsis sp., Stephanodiscus hantzschii, Komma caudate, Lyngbya sp. and Cryptomona~ marssonii were the dominant species, and phytoplankton assemblages were significantly different among seasons. The phytoplankton community was the simplest in spring, and then in summer.The most complicated community occurred in autumn and winter. Ca- nonical correspondence analysis showed that water temperature and nutrients were the most important environmental factors affecting the phytoplankton community structure. Irradiance, permanganate index, oxidation-reduction potential, and dissolved organic carbon also were the key environmental factors affecting the phytoplankton community structure in autumn and winter.