Phytoplankton community structure and its driving factors in autumn in Jinan, China

Abstract

Human activities often cause multiple impacts on aquatic ecosystems, including changes in water quality, biodiversity, community composition, etc. However, the effects of human activities on phytoplankton in highly urbanized aquatic ecosystems are poorly understood. In this study, we conducted an in-depth analysis of phytoplankton communities and water environment factors in the Jinan City watershed in September 2020, focusing on 18 water environment factors. We found that nitrate nitrogen, total nitrogen, total phosphorus, and phosphate were the key drivers affecting the quality of the water environment in the area through principal component analysis (PCA). The results of the phytoplankton investigation showed that 143 species of phytoplankton from 8 phyla were found in the Jinan watershed, dominated by Chlorophyta, Bacillariophyta, and Cyanobacteria, of which cyanobacteria were dominant in density, while cryptophytes were the first in biomass. The assessment of phytoplankton diversity showed that the Jinan City watershed had high biodiversity, with an average Shannon Wiener Diversity Index of 3.12. RDA analysis revealed that permanganate index, total phosphorus, bathymetry, chlorophyll a, pH, and phosphate were significantly correlated with the structure of the phytoplankton community. Comprehensive trophic index (TLI) analysis showed that most of the watersheds in Jinan were moderately eutrophic. These results provide essential information for understanding the water quality status and aquatic biodiversity in Jinan City watersheds and provide a scientific basis for water environment management and protection.