洱海流域沿岸带石质基质上周丛藻类群落研究

Investigation of epilithic periphyton communities of the littoral zone of the lakes in Erhai watershed

2009年12月-2010年1月调查了云南洱海流域中洱海、西湖和茈碧湖沿岸带周丛藻类群落的物种组成、生物量、群落多样性以及水体理化因子，并运用典范对应分析（CCA）探讨了影响周丛藻类群落结构的主要环境因子．结果表明洱海周丛藻类优势种属是刚毛藻属、等片藻属、暗丝藻，而西湖和茈碧湖均以硅藻为主．洱海的周丛藻类生物量大于西湖和茈碧湖，最高值出现在洱海白族小庙（EH31），Chl—a达到78．71ug／cm2．洱海的绿藻密度也高于西湖和茈碧湖．茈碧湖的周丛藻类多样性最高，Shannon—wiener指数均值为2．47；西湖次之。Shannon—wiener指数均值为2．34；而处于流域下游的洱海沿岸带周丛藻类的耐污种数目增加，多样性最低．CCA结果表明水体中的NH4＋及TP浓度是影响洱海流域物种分布的主要环境因子．

Species composition, biomass, biodiversity of periphyton community as well as the aquatic physical and chemical characteristics along the littoral zone of three lakes in Erhai watershed, including Lake Erhai, Lake Xihu and Lake Cibihu, were investigated during December 2009 to January 2010. The dominant periphyton species in Lake Erhai were Cladophora spp. Diatoma spp. and Psephonema aenigmat, whereas the periphyton communities of Lake Xihu and Lake Cibihu were dominated by diatom species. Biomass of periphyton in Lake Erhai was significantly higher than those in Lake Xihu and Lake Cibihu. The highest periphyton biomass （Chl-a as 78.71ug/cm2） was observed at site EH31. Proportion of green algae in periphyton of Lake Erhai was also the highest among the three lakes. Algal biodiversity of the periphyton communities of Lake Cibihu, expressed by Shannon-wiener index, was the highest （2.47）, compared with that of Lake Xihu and Lake Erhai as 2.34 and 2.20, respectively. The results indicated that algal biodiversity decreased but pollution tolerant species richness increased at the downstream of Erhai watershed. Statistical analysis by CCA showed that NH4＋ and TP in water body were the main factors determining the periphyton species distribution in Erhai watershed.