Spatial And Temporal Distribution Characteristics Of Bacterioplankton Community In Typical Waters Of The Pearl River

This study investigated three typical waters of the Pearl River:the Pearl River Delta,the main stream of North River and the Zhaoqing Star Lake,and analyzed the spatial and temporal distribution of bacterioplankton communities and their correlation with environmental factors.The results of community composition analysis showed that,the bacterial community in the three waters was classified at the level of phylum,mainly by Proteobacteria,Actinobacteria,Bacteroidetes,Verrucomicrobia and Cyanobacteria.At the level of class,it was mainly composed of?-proteobacteria,?-proteobacteria,?-proteobacteria and Actinobacteria.The results of this study in the Pearl River Delta showed that,in season,the diversity index of Shannon and Chao 1 in the wet season was higher than in the dry season,and the difference between Bacilli and Flavobacteriia was significant.In space,The Pearl River Delta could be divided into the main stream of Xijiang River,the Central Pearl River Delta and the surrounding areas of Guangzhou.RDA analysis showed that water temperature(WT),dissolved oxygen(DO),phosphate(PO₄^3-),silicate(Si O₄^2-),total phosphorus(TP)and transparency(SD)were the most significant environmental factors driving the change in bacterial community(P<0.05),and might have affected the increment metabolism of bacteria.Water temperature and transparency were important factors affecting seasonal differences,these distinguished between high and low season stations;DO;chemical oxygen demand(COD);and nutrients(PO₄^3-,Si O₄^2-,TP)were important factors affecting spatial differences;these distinguished stations of the main stream of Xijiang River,the Central Pearl River Delta and the surrounding areas of Guangzhou.PICRUSt functional predictive analysis showed that transporters,ABC transporters and DNA repair and recombination proteins were the main functions expressed by the bacterioplankton community in the Pearl River Delta.The ABC transporters and transporters were significantly higher in the wet season than in the dry season.The results of this study in the main stream of North River showed that,in season,the diversity index of Chao 1 in August was higher than in April,and the difference between?-proteobacteria and Oxyphotobacteria was significant;in space,the main stream of North River could be divided into three regions:upstream,midstream and downstream.RDA analysis showed that SD,WT,p H,salinity(S),oxidation-reduction potential(ORP)and Si O₄^2-were the most significant environmental factors driving the change in bacterial community(P<0.05),and could affect bacterial growth and reproduction.Water temperature,salinity and oxidation-reduction potential were important factors affecting seasonal differences,these distinguished stations in April and August;PO₄^3-and TP were important factors affecting spatial differences;these distinguished stations of the main stream of North River Upstream,Midstream,Downstream.PICRUSt functional predictive analysis showed that Membrane Transport;Amino Acid Metabolism;Carbohydrate Metabolism;Replication and Repair,and Energy Metabolism were the main functions expressed by the bacterioplankton community in the main stream of North River.The results of this study in the Zhaoqing Star Lake showed that,the Star Lake stations were divided into five groups by non-metric multidimensional scale analysis(NMDS).RDA analysis showed that SD was the most significant environmental factor driving the change in bacterial community(P<0.01).There were differences in the composition and diversity of bacterial communities at different stations and the correlations with environmental factors.PICRUSt functional predictive analysis showed that Membrane Transport;Carbohydrate Metabolism;Amino Acid Metabolism;Replication and Repair,and Energy Metabolism were the main functions expressed by the bacterioplankton community in the Star Lake.This study showed that under the combined action of multiple environmental factors,different waters have formed their unique bacterial community structure.The results of this study affirmed the important role of bacterioplankton community in typical waters of the Pearl River,and could provide a scientific reference for aquatic ecological environmental protection in typical waters of the Pearl River.