新疆乌伦古湖春、秋季浮游植物群落结构的聚类和多维分析

Cluster analysis and multidimensional scaling analysis in spring and autumn of phytoplankton community structure of Ulungur Lake,Xinjiang

2007年4月和8月对乌伦古湖浮游植物进行了调查。经鉴定,调查区域内浮游植物共计8门172种(含未定种)。其中绿藻门74种(含未定种),硅藻门50种(含未定种),蓝藻门27种(含未定种),其他种类占12.2%。4月浮游植物平均细胞密度和生物量分别为33.49×104ind/L和0.4552mg/L;8月分别为276.28×104ind/L和3.6578mg/L。依据浮游植物物种组成和细胞密度,利用Bray-Curtis相似性测定,对浮游植物群落结构进行聚类(Cluster analysis)和多维(Multidimensional scaling,MDS)分析。结果显示,春、秋季布伦托海浮游植物群落结构聚为两大类,吉力湖聚为三大类;由于各采样点的水深、水温、pH值、透明度等环境因子的差异导致浮游植物群落结构发生变化,采用聚类和多维分析,有效地揭示了乌伦古湖春、秋季各采样点间浮游植物群落结构的相似性;多维分析与聚类分析结果一致,从二维空间角度证实了聚类结论。乌伦古湖属高纬度地区水体,春、秋两季出现以硅藻为优势类群的浮游植物群落类型;结合乌伦古湖浮游植物的优势种、数量和生物量的检测结果,该湖属于贫-中营养型湖泊。本研究旨在群落结构层面探讨春、秋季乌伦古湖浮游植物的变化规律,为今后进一步合理利用该湖丰富的水生生物资源提供科学依据。

Ulungur Lake was the second largest lake by surface area （931 km^2） and volume （1.04 × 10^10 m^3） after Bosten Lake in Xinjiang Uygur Autonomous Region, which is located in the north of Junggar basin and made up of Buluntuo Lake and Jili Lake. The phytoplankton of Ulungur Lake was studied in April and August 2007. The phytoplankton assemblage was composed of 172 species in total, belonging to 8 taxonomic groups. Chlorophyta were represented by the highest number of taxa （74） followed by Bacillariophyta （50）, Cyanophyta （27）, Euglenophyta （7）, Dinophyta （6）, Chrysophyta （4）, Cryptophyta （3） and Xanthophyta （1）, in which unconfirmed taxa were found in 172 taxa. The average cell density ranged from 33.49~ 104 ind/L in April to 276.28 X 104 ind/L in August, while the average biomass ranged from 0.4552 mg/L in April to 3.6578 mg/L in August. According to species composition and cell density, the cluster analysis and multidimensional scaling （MDS） of phytoplankton community structure were carried out by Bray-Curtis index. The results revealed that phytoplankton community of Buluntuo Lake can be classified to two groups in spring and autumn, while that of Jili Lake can be classified to three groups. However, in different seasons, the results of cluster and MDS analysis were different because of diverse geographic environment and ecologic environment such as depth, temperature, pH and transparency. At the same time, both the MDS analysis and cluster analysis revealed the same results, which certified the result of cluster analysis from 2-dimentional space. The similarity of phytoplankton community structure was revealed efficiently among different sampling stations in spring and autumn, and the variation of phytoplankton community structure was also discussed in Ulungur Lake. The research also revealed that Bacillariophyta was dominant in Ulungur Lake in spring and autumn. According to dominant species, density and biomass ofphytoplankton in spring and autumn, Ulungur Lake belong to oligotrophic- mesotrophic lake. The aim of this paper was to discuss variation law of phytoplankton community in Ulungur Lake and to provide scientific evidence for rational use affluent hydrobiont resources in the future. [Journal of Fishery Sciences of China, 2008, 15 （6） ： 984-991]