基于SOM的乌梁素海浮游植物群落结构研究

Application of Self-organizing Map to Analysis of Phytoplankton Community Structure in Wuliangsuhai Lake,China

浮游植物能够产生氧气并为其他生物提供食物,维持其他生命的生存,进而保证水生态系统的平衡,在水生态系统中具有重大意义。为研究寒旱区乌梁素海浮游植物群落结构特征及其与环境因子的关系,运用自组织特征映射网络(SOM),并结合完全连接法,将乌梁素海浮游植物分为8个群落类型,分别为群落Ⅰ(蓝藻Cyanobacteria-绿藻Chlorophyta-硅藻型Bacillariophyta)、群落Ⅱ(蓝藻型)、群落Ⅲ(硅藻型)、群落Ⅳ(硅藻-绿藻型)、群落Ⅴ(硅藻-蓝藻型)、群落Ⅵ(绿藻-硅藻型)、群落Ⅶ(绿藻-硅藻型)、群落Ⅷ(绿藻-硅藻-蓝藻型)。分类结果显示,各群落结构的物种组成呈现明显特征,优势种的分布具有显著的规律性。利用Kruskal-Wallis方法分析群落类型间环境因子的差异性,结果显示,各群落类型的水深、水温、p H、总磷具有极显著性差异(P<0.01),而透明度、总氮、电导率显著性差异不显著(P>0.05)。通过对群落类型与其环境因子的分析,结合国内外浮游植物功能群及其生境的研究,发现优势属小环藻(Cyclotella)、舟形藻(Navicula)、衣藻(Chlamydomonas)适应低温、浅水及高营养盐的水域环境;栅藻(Scenedesmus)、绿球藻(Chlorococcum)、针杆藻(Synedra)适应总氮、总磷浓度均较高的水域环境;而平裂藻(Merismopedia)、色球藻(Chroococcus)适应高温、深水、总磷浓度较低的水域环境。温度是乌梁素海浮游植物群落结构组成的决定因子,而氮磷比可能是影响群落组成的又一重要环境因子。

Phytoplankton can produce oxygen and food,which sustain all other life forms, ensuring aquatic ecological balance. Phytoplankton played an important role in aquatic ecosystems. The aim of the present study was to investigate the phytoplankton community and its relationship with different environmental factors in Wuliangsuhai Lake, Inner Mongolia. In the present research, self-organizing map （SOM） combined with fully connected method was applied to classify the phytoplankton community. The phytoplankton community was classified into eight groups, respectivelyⅠ（Cyanobacteria-Chlorophyta-Bacillariophyta）, Ⅱ（Cyanobacteria）, Ⅲ （Bacillariophyta）, Ⅳ （Bacillariophyta-Chlorophyta）, Ⅴ （Bacillariophyta-Cyanobacteria）, Ⅵ （Chlorophyta- Bacillariophyta）, Ⅶ （Chlorophyta-Bacillariophyta）, Ⅷ （Chlorophyta-Bacillariophyta-Cyanobacteria）. The characteristic of community structure was obvious. The distribution of dominant species was regular. The method of Kruskal Wallis was used to analyze the differences of environmental factors between each phytoplankton community. Water depth, water temperature, pH, and total phosphorus of phytoplankton communities were significantly different （P〈0.01）; transparency, total nitrogen, and electrical conductivity were similar among different communities （P〉0.05）. Analysis of the community and environmental factors , Combining with the results of the functional group, Cyclotella, Navicula, Chlamydomonas were more suitable in the environment like the lower water temperature and water depth, as well as the higher concentrations of TP and TN; Scenedesmus, Chlorococcum, Synedra were more suitable in the environment like high concentration of TP and TN; Merismopedia, Chroococcus were more suitable in the environment like the higher water temperature and water depth, lower concentration of TP. The analysis results showed that water temperature was key factors of phytoplankton community structure, nitrogen and phosphorus might be another important factor of phytoplankton community structure.