新疆额尔齐斯河周丛藻类群落结构特征研究

STUDIES ON THE COMMUNITY STRUCTURE OF PERIPHYTON IN THE IRTYSH RIVER OF XINJIANG UYGUR AUTONOMOUS REGION

周丛藻类是新疆跨境河流土著及特有鱼类重要的基础饵料资源,然而在该地区有关周丛藻类的研究目前尚属空白。有鉴于此,2012年7、8、10月对新疆跨境河流——额尔齐斯河全流域的周丛藻类群落结构进行了系统的调查分析。结果表明,周丛藻类隶属7门70属178种,由硅藻门、绿藻门、蓝藻门、裸藻门、黄藻门、金藻门和甲藻门组成,其中硅藻门有92种并占据绝对优势(51.7%),绿藻门49种(30.3%),蓝藻门20种(11.8%),裸藻门5种(2.8%),黄藻门3种(1.7%),金藻门2种(0.1%),甲藻门仅1种(0.6%),周丛藻类在不同月份的种类数存在显著差异(P<0.01)。优势种主要为硅藻门的嗜盐舟形藻(Navicula halophila)、钝脆杆藻(Fragilaria capucina Desm)、极小桥弯藻(Cymbella perpusilla Cl)以及蓝藻门的皮状席藻(Phormidium corium Gom)等。研究期间,额尔齐斯河周丛藻类的密度和生物量的均值分别为1105.5×106 ind./m2和2692.0 mg/m2,不同月份间密度和生物量的分布差异不显著,但在空间分布上整体趋势为中下游地区高于上游地区。水温和营养盐成为影响其分布的主要环境因子。Simpson多样性指数、Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数的平均值分别是0.38、3.04、0.66和2.55。运用多样性指数和藻类丰度对额尔齐斯河水质评价为轻度污染。

Periphyton acts as the primary basal food resource of indigenous and unique fishes in the cross-border rivers of Xinjiang Uygur Autonomous Region. Research of the periphyton in this region is still limited. To investigate the community structure of periphyton, samples were collected in July, August and October 2012 from Irtysh River located in Xinjiang Uygur Autonomous Region. Our study indicated that the periphyton assemblage was composed of 178 spe-cies in total, belonging to seven taxonomic groups. Bacillariophyta showed the highest number of taxa (92), followed by Chlorophyta (49), Cyanophyta (20), Euglenophyta (5), Cryptophyta (3), Chrysophyta (2) and Pyrrophyta (1). Species number of periphyton showed significantly differences in different seasons (P<0.01). Bacillariophyta was predominant in species composition, especially N. halophila, Fragilaria capucina, C. perpusilla and Phormidium corium Gom. The average cell density and biomass of periphyton were 1105.5 ind./m2 and 2692.0 mg/m2, respectively. Although seasonal and spatial distribution of density and biomass were not significant difference, the overall trend of spatial distribution showed that the density and biomass in lower-middle region were higher than those in upper region. Average values of diversity indices (D, H′), evenness (J) and abundance (Dm) of periphyton were 0.38, 3.04, 0.66 and 2.55, respectively. The water quality of Irtysh River has mild contamination based on the diversity index and phytoplankton abundance.