渭河陕西段浮游植物群落结构时空变化与影响因子分析

浮游植物是水生态系统的初级生产者，其群落结构与水环境密切相关.为了解渭河陕西段浮游植物群落结构时空格局及其与环境因子的关系，更好地进行水资源和水生态保护，于2017年9月—2018年4月在丰水期和枯水期对该河段设定的9个研究断面，27个采样点位进行浮游植物群落结构和水环境因子调查监测，共检出浮游植物8门69种，群落结构分析表明，枯水期浮游植物种类数高于丰水期.浮游植物细胞密度和生物量变化分别为84.9×10⁴~3868.3×10⁴ cells·L^-1、0.268~20.978 mg·L^-1，丰水期平均密度（1490.0×10⁴ cells·L^-1）和平均生物量（7.864 mg·L^-1）显著大于枯水期（354.8×10⁴ cells·L^-1、1.152 mg·L^-1）.优势种分别为6种和8种，主要以绿藻门和硅藻门为主.浮游植物Shannon-Wiener指数（H''）、Pielou均匀度指数（J）、Margalef丰富度指数（d）均表明丰水期浮游植物多样性高于枯水期，9个采样断面的水质总体评价呈现出无污染或轻度污染至中轻污染状态.典范对应分析（CCA）排序结果表明，影响枯水期浮游植物群落结构的主要环境因子为总磷（TP）、pH和总溶解性固体（TDS），TP和高锰酸盐指数（COD_Mn）是影响丰水期浮游植物群落结构的主要环境因子.

Spatio-temporal characteristics and influencing factors of phytoplankton community structure in the Shaanxi Section of Weihe River, China

Phytoplankton is a major producer of water ecosystems,and its community structure is closely related to water quality.In order to reveal the characteristics of phytoplankton community structure and its influencing factors,and provide scientific basic data for conserving water resources in the Shaanxi section water bodies of Weihe Rive,this study selected 9 transects (27 sampling sites) to investigate the phytoplankton community and water environment in September 2017(wet season) and April 2018(dry season).A total of 69 phytoplankton species were identified,which belong to 8 phyla.Community structure analysis showed that the species composition of phytoplankton in wet season was the lower than that in dry season.The density and biomass of phytoplankton was 84.9×10⁴~3868.3×10⁴ cells·L^-1and 0.268~20.978 mg·L^-1,respectively.The average density of 1490.0×10⁴ cells·L^-1 and average biomass of 7.864 mg·L^-1 in wet season were significantly greater than that (354.8×10⁴ cells·L^-1 and 1.152 mg·L^-1) in dry season.The dominant species were 6 species and 10 species and were mainly Chlorophyta and Bacillariophyta.The Shannon-Wiener diversity index (H''),Pielou evenness index (J) and Margalef richness index (d) of phytoplankton community all indicated that the diversity of phytoplankton in wet season was higher than that in dry season.Through the diversity index,the water quality in the Shaanxi section of Weihe River was found to range from being unpolluted to light or moderately polluted.A canonical correspondence analysis (CCA) showed that the community structure of phytoplankton in the Shaanxi section of Weihe River was primarily affected by the environmental factors including total phosphorus (TP),pH and total dissolved solids (TDS) in dry season, and total phosphorus(TP) and permanganate index(COD_Mn) in wet season.