[Characteristics of Phytoplankton Community Structure and Their Relationships with Environmental Factors in Autumn in Qinhe River Basin of Jincheng Region].

In October-November 2020, the phytoplankton and the aquatic environment from 62 sites in the mainstream of the Qinhe River and the largest tributary of the Qinhe River (Danhe River) in the Jincheng region were investigated to clarify the spatial pattern of phytoplankton communities and their driving factors. A total of 7 phyla and 47 species of phytoplankton were identified in the Qinhe River basin and were composed of Cryptophyta, Chlorophyta, Pyrrophyta, Chrysophyta, Bacillariophyta, Cyanophyta, and Crytophyta. Six dominant species in the Qinhe River included:, and . Six dominant species in the Danhe River included: Lemm, and . The Shannon-Wiener diversity index () varied from 0.35 to 3.15, with a mean value 1.40. The Pielou evenness index () varied from 0.24 to 1.00, with a mean value of 0.68. values in the Qinhe River were higher than those in the Danhe River. values were relatively low in the middle reaches of the Qinhe River and middle-low reaches of the Danhe River. The results in the Qinhe River through a canonical correspondence analysis (CCA) showed that the percent of forest land at a 300 m buffer was the driving factor of in Chlorophyta, and nitrate, total phosphorus, and the percent of forest land at the 300 m buffer were the driving factors of . was mainly influenced by the percent of urban land and water temperature, whereas , and were mainly influenced by the percent of farmland and residential land at the 300 m buffer. The results in the Danhe River via CCA showed that and were mainly influenced by pH and sulfate, was mainly influenced by the percent of urban land and grass land, was mainly influenced by chloride and the percent of forest land, was mainly influenced by water temperature and the percent of farmland, and was mainly influenced by ammonia and the percent of farmland.