The Relationship between the Community Structure and Function of Bacterioplankton and the Environmental Response in Qingcaosha Reservoir

Shumin Liu,Fengbin Zhao,Xin Fang

doi:10.3390/w13223155

Shumin Liu, Fengbin Zhao + Show 1 more

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https://doi.org/10.3390/w13223155

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Abstract

Phytoplankton and bacterioplankton play a vital role in the structure and function of aquatic ecosystems, and their activity is closely linked to water eutrophication. However, few researchers have considered the temporal and spatial succession of phytoplankton and bacterioplankton, and their responses to environmental factors. The temporal and spatial succession of bacterioplankton and their ecological interaction with phytoplankton and water quality were analyzed using 16S rDNA high-throughput sequencing for their identification, and the functions of bacterioplankton were predicted. The results showed that the dominant classes of bacterioplankton in the Qingcaosha Reservoir were Gammaproteobacteria, Alphaproteobacteria, Actinomycetes, Acidimicrobiia, and Cyanobacteria. In addition, the Shannon diversity indexes were compared, and the results showed significant temporal differences based on monthly averaged value, although no significant spatial difference. The community structure was found to be mainly influenced by phytoplankton density and biomass, dissolved oxygen, and electrical conductivity. The presence of Pseudomonas and Legionella was positively correlated with that of Pseudanabaena sp., and Sphingomonas and Paragonimus with Melosira granulata. On the contrary, the presence of Planctomycetes was negatively correlated with Melosira granulata, as was Deinococcus-Thermus with Cyclotella sp. The relative abundance of denitrifying bacteria decreased from April to December, while the abundance of nitrogen-fixing bacteria increased. This study provides a scientific basis for understanding the ecological interactions between bacteria, algae, and water quality in reservoir ecosystems.

Highlights

Qingcaosha Reservoir is the largest salt-avoidance freshwater reservoir in the world.It is an important drinking water source in Shanghai, representing around 50% of the total raw water consumed in this city
The Nitrosomonas, Nitrosospira, and Hydrogenophaga genera of β-proteobacteria are involved in the nitrogen metabolism of freshwater systems, and have the ability to degrade complex organic macromolecules, but are rarely found in the ocean [36], which may be related to the recharge of the salt tide in the reservoir
The results show that the effects of environmental factors on the bacterial community differed in time and space, and that specific environmental factors had a weak correlation to the bacteria found at fixed sites and a strong correlation at a fixed time, and these same environmental factors had a different influence on the bacterial community in different months

Summary

Introduction

Qingcaosha Reservoir is the largest salt-avoidance freshwater reservoir in the world. It is an important drinking water source in Shanghai, representing around 50% of the total raw water consumed in this city. Qingcaosha Reservoir is located in the Yangtze River Delta, a densely populated area that is currently undergoing rapid economic development. The reservoir is prone to eutrophication [3], which increases risks that compromise the safety of the drinking water for residents [4]. It is crucial to ensure good ecological quality and safety of the water for resident health. Much research has been conducted on the water quality [5], hydrodynamics [6], and zooplankton and phytoplankton [7] in the reservoir area. There has been little research on the bacterioplankton in the reservoir

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