甘河着生藻类群落结构及其与环境因子的关系

2018年8月(丰水期),在嫩江支流甘河,调查了19个点位的着生藻类群落结构和水环境特征。并运用聚类分析、Mcnaughton优势度分析和IBD(biological diatom index,硅藻生物指数)3种方法研究了甘河着生硅藻群落结构和优势种清洁状况,使用主成分分析、Spearman相关分析和冗余分析等统计分析方法研究了甘河着生硅藻群落和环境因子的响应关系。结果表明:甘河共鉴定出着生藻类90种(属),以硅藻门、绿藻门和蓝藻门为主,生物量丰富。丰水期甘河水生态环境质量状况较为健康,着生硅藻主要由清洁种构成,其中Achnanthidium minutissimum优势度0.48,为绝对优势种。聚类分析结果表明,甘河采样点位可分为3组;其中组1和组2点位主要位于甘河上、中游,上、中游水质、生境质量较好,健康程度较高,优势种均为清洁种,上游Achnanthidium minutissimum优势度达到了0.64;组3点位均位于甘河下游,下游人为干扰较强,健康程度较其余两组偏低,Nitzschia palea和Nitzschia paleaeformis等耐污种在组3的优势度较高。导致甘河着生硅藻群落清洁度由上游到下游逐渐变差的主要水环境因子为电导率、总磷和高锰酸盐指数,其中影响中游硅藻群落结构变化的主要水环境因子为高锰酸盐指数,影响下游硅藻群落结构变化的主要水环境因子为电导率和总磷。由此可见,着生硅藻群落可以较好的指示甘河流域水体有机污染程度和营养富集程度。

Community Structures of Periphyton and Their Relationship with Aquatic Environmental Factors in the Gan River,China

In order to reasonably evaluate the eco-environmental health of Gan River, which is a tributary of the Nen River in China, community structures of periphyton and cleanliness of the benthic diatom at 19 sampling sites were investigated using clustering, Mc Naughton’s dominance index and biological diatom index, while the relationship between the environmental factors and the diatom communities were studied by the principal component analysis, Spearman correlation test and redundancy analysis in August 2018(flood season). A total of 90 species or genuses of periphyton have been identified, most of which are diatoma, chlorophyta and cyanophyta, indicating that there were abundant algaes in the Gan River. Achnanthidium minutissimum and other diatoms which can be used as clean water indicators were dominant species in the Gan River, indicating that the eco-environmental quality of Gan River was relatively healthy in the flood season. Among them, the dominant degree of A. minutissimum was 0.48, which was the predominated species in the Gan River. Sampling sites can be divided into three groups based on clustering analysis, and the sites of group 1 and group 2 are mainly located in the upper and middle reaches of Gan River. The quality of water and habitats in the upper and middle reaches of Gan River were relatively good. The dominant species of group 1 and group 2 were mainly clean species, indicating that the two groups were in a relatively healthy state, among them, the dominant degree of A. minutissimum of group 1 was 0.64. The sites of group 3 are all located in the lower reaches of Gan River, which was subject to strong human disturbance. Nitzschia palea, Ulnaria ulna and other diatoms which can be used as eutrophication indicators were the dominant species of group 3, indicating that group 3 was less healthy than the other two groups. The predominant aquatic influencing factors that lead to the gradual deterioration of the cleanliness of diatom communities in the Gan River from upstream to downstream were electrical conductivity, total phosphorus and permanganate index. Among which permanganate index was the main factors for middle reaches, while electrical conductivity and total phosphorus were for lower reaches. As a result, except for the lower reaches of the river, the eco-environmental quality of the Gan River was good, the benthic diatom was found to be an effective indicator for the nutritional conditions and organic pollution status.