Abstract:

As the largest branch of the Yellow River, the Weihe River is an important research area for ecological protection and high-quality development of the Yellow River Basin. In order to understand the composition and structure of plankton and the status of ecologic environment of the Weihe River, four water ecological surveys were conducted in autumn 2017 and spring 2018 to investigate the plankton community structure characteristics and determine their influencing factors. The results showed that 53 phytoplankton species belonged to 8 phyla, among which green alga (43.4%) and diatom (33.9%) species had higher richness. In addition, 30 zooplankton species belonged to 4 major categories, with the dominant rotifers accounting for 50.0%. The dominant species of plankton in the Weihe River were Cyclotella meneghiniana, Eunotia pectinalis, Chlorella vulgaris, Difflugia globulosa, and Accomorpha saltans. The composition of plankton species in different locations showed the following pattern: downstream > the midstream>the upstream. In the spring, the average density (2.115×10⁶ cell∙L^-1) and average biomass (0.432 mg∙L^-1) of phytoplankton were higher than those in the autumn (1.630×10⁶ cell∙L^-1, 0.352 mg∙L^-1). On the contrary, the average density (9.864 ind∙L^-1) and average biomass (10.219 µg∙L^-1) of zooplankton in the autumn were higher than those in the spring (4.984 ind∙L^-1, 3.168 µg∙L^-1). The average Shannon-Weiner diversity index (H′), the average Pielou evenness index (J) in the autumn, and the average Margalef richness index (d) of plankton were 2.519, 0.798, 1.394, respectively. Based on the plankton diversity index, the evaluation results showed that the water was slightly polluted and the plankton community structure tended to be simplified in the Weihe River. The canonical correspondence analysis results showed that the altitude (ALT) and water depth (WD) were the main environmental factors affecting the phytoplankton community structure, and the altitude (ALT), dissolved oxygen (DO), and pH were the main environmental factors affecting the zooplankton community structure in the Weihe River. To some extent, the quality of the water environment had been changed by the integrated river management and water pollution control. In addition, the variation of the water quality affected the succession of the plankton community structure. This study can provide a basis for and guide future ecological restoration of the Weihe River.

Key words: Weihe River, plankton, community structure, canonical correspondence analysis, evaluation of water quality

摘要：

渭河是黄河第一大支流,是黄河流域生态保护与高质量发展的重要研究区域。为了掌握渭河浮游生物组成结构及生态环境现状,于2018—2019年分两个季节在渭河开展4次水生态调查,研究分析了渭河浮游生物群落结构特征及其影响因子。调查结果显示,浮游植物有8门53种,以绿藻门和硅藻门为主,占比分别为43.4%、33.9%;浮游动物4类30种,以轮虫为主,占比为50.0%。渭河浮游生物优势种主要为梅尼小环藻（Cyclotella meneghiniana）、篦形短缝藻（Eunotia pectinalis）、小球藻（Chlorella vulgaris）、球形砂壳虫（Difflugia globulosa）、舞跃无柄轮虫（Accomorpha saltans）。种类数均呈现下游>中游>上游,春季浮游植物平均密度（2.115×10⁶ cell∙L^-1）和平均生物量（0.432 mg∙L^-1）均高于秋季（1.630×10⁶ cell∙L^-1,0.352 mg∙L^-1）,秋季浮游动物平均密度（9.864 ind∙L^-1）和平均生物量（10.219 µg∙L^-1）均高于春季（4.984 ind∙L^-1,3.168 µg∙L^-1）。浮游生物Shannon-Weiner多样性指数（H′）、Pielou均匀度指数（J）和Margalef丰富度指数（d）均值分别为2.519、0.798、1.394。浮游生物多样性指数评价结果表明,渭河水质属于轻度污染,浮游生物群落结构趋于简单化。典范对应分析显示,海拔和水深是影响渭河浮游植物群落结构的主要环境因子,海拔、溶解氧和pH是影响渭河浮游动物群落结构的主要环境因子。河道综合治理与水体污染控制在一定程度上改变了渭河水环境质量,从而影响了浮游生物群落结构演替。该研究可为渭河河道生态修复工作提供依据,具有一定的区域指导意义。

关键词: 渭河, 浮游生物, 群落结构, 典范对应分析, 水环境质量评价