Composition And Predictive Functional Analysis Of Bacterial Communities In The Changjiang Estuary And The East China Sea

The objective of this study was to characterize the structure and function of microbial communities in surface seawater from the Changjiang Estuary and adjacent areas,China.Samples were collected at 12 sites and environmental parameters were measured.The bacterial communities was analyzed via high-throughput sequencing of the 16S rDNA genes.Meanwhile,predictive metagenomic approach investigated the putative functions of each bacterial community.Results showed that sample site A0102 had the highest bacterial abundance and diversity.Phylogenetic analysis revealed that Proteobacteria,Bacteroidetes and Actinobacteria were the predominant phyla occurring throughout the samples examined.Redundancy analysis?RDA?identified that PO₄^3–concentration had positive correlations with the bacterial communities and microbial functional diversity.Furthermore,microbial assemblages in the sites?A0102/B0102/C0102/B0202?which near the shore had higher predicted metabolic potentials in amino acid metabolisms,energy metabolisms,sulfur metabolisms,and methane metabolisms.This study adds to our knowledge of functional and taxonomic composition of microbial communities in the Changjiang Estuary.The objective of this study was to characterize the bacterial community structures and their functions in surface sediment from the East China Sea.Sediment samples were collected from 8 sites along a transect from the Changjiang Estuary to open ocean.The community structure was analyzed using high-throughput sequencing of 16S rDNA genes.We used a predictive metagenomic approach to predict the functions of bacterial community.Sample site DH213 had the highest bacterial abundance and diversity while site DH63 the lowest.Phylogenetic analysis indicated that Proteobacteria was the predominant phylum in all samples,followed by Planctomycetes and Acidobacteria.Deltaproteobacteria and Gammaproteobacteria were the dominant classes.The heat map revealed that the different samples can be clustered into six groups and the abundance of bacteria was obtained directly from it.From the analysis of predictive metagenomic,we found that oxidative phosphorylation,carbon fixation pathways in prokaryotes,methane metabolism,nitrogen metabolism,carbon fixation in photosynthetic organisms and xenobiotics biodegradation and metabolism were enriched in all samples.Furthermore,there were significant correlations between functional potentials and taxonomic composition.This study adds to our knowledge of functional and taxonomic composition of microbial communities.Marine sediment bacteria play an important role in the global cycling of elements.The objective of this study was to characterize the bacterial community structures and their functions in different depth of sediment from the East China Sea.Sediment samples were collected from 4 sites along a transect from the Changjiang Estuary to open ocean.The community structure was analyzed using high-throughput sequencing of 16S rDNA genes while predictive metagenomic approach was used to investigate the functions of bacterial community.We inferred the shifts of topological features in co-occurrence networks from the Changjiang Estuary to open sea.Our results indicated a significant difference of community structure among four sites.Meanwhile,the community structure varied with depth.The microbial richness,as estimated by Chao1 index and ACE index,decreased as the depth increased.The microbial diversity,estimated by Shannon index also played a similar trend.Phylogenetic analysis revealed that Proteobacteria,Planctomycetes,Acidobacteria and Chloroflexi were the predominant phyla throughout the depth examined.At the class level,Alphaproteobacteria,Gammaproteobacteria,Deltaproteobacteria,and Planctomycetia dominated in all samples.Co-occurrence networks revealed that open ocean microbial shared more niche spaces.Based on predictive metagenomic analysis,we found that amino acid,energy,sulfur and methane metabolism were inhibited in the Changjiang Estuary.This study adds to our knowledge of depth-related taxonomic composition and functions in the sediments of the East China Sea.