Comparative analysis of bacterioplankton assemblages from two subtropical karst reservoirs of southwestern China with contrasting trophic status

Qiang Li,Shenglin Xin,Zhongyi Li,Yadan Huang

doi:10.1038/s41598-020-78459-z

Abstract

Although bacterioplankton play an important role in aquatic ecosystems, less is known about bacterioplankton assemblages from subtropical karst reservoirs of southwestern China with contrasting trophic status. Here, 16S rRNA gene next-generation sequencing coupled with water chemistry analysis was applied to compare the bacterioplankton communities from a light eutrophic reservoir, DL Reservoir, and a mesotrophic reservoir, WL Reservoir, in subtropical karst area of southwestern China. Our findings indicated that Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria and Verrucomicrobia dominated bacterioplankton community with contrasting relative frequency in the two subtropical karst reservoirs. Proteobacteria and Bacteroidetes were the core communities, which played important roles in karst biogeochemical cycles. Though WT, TN and DOC play the decisive role in assembling karst aquatic bacterioplankton, trophic status exerted significantly negative direct effects on bacterioplankton community composition and alpha diversity. Due to contrasting trophic status in the two reservoirs, the dominant taxa such as Enterobacter, Clostridium sensu stricto, Candidatus Methylacidiphilum and Flavobacteriia, that harbor potential functions as valuable and natural indicators of karst water health status, differed in DL Reservoir and WL Reservoir.

Highlights

Bacterioplankton play an important role in aquatic ecosystems, less is known about bacterioplankton assemblages from subtropical karst reservoirs of southwestern China with contrasting trophic status
To probe the response of bacterioplankton communities to trophic status in freshwater ecosystems in depth, Ji et al found that eutrophic lakes were dominated by Cyanobacteria, yet oligotrophic lakes were dominated by Actinobacteria in Wuhan, C hina[7]
16S rRNA gene next-generation sequencing coupled with analysis of water chemistry was used to explore the bacterioplankton assemblages in two subtropical karst reservoirs with contrasting trophic status from southwestern China

Summary

Introduction

Bacterioplankton play an important role in aquatic ecosystems, less is known about bacterioplankton assemblages from subtropical karst reservoirs of southwestern China with contrasting trophic status. Our findings indicated that Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria and Verrucomicrobia dominated bacterioplankton community with contrasting relative frequency in the two subtropical karst reservoirs. Proteobacteria and Bacteroidetes were the core communities, which played important roles in karst biogeochemical cycles. Though WT, TN and DOC play the decisive role in assembling karst aquatic bacterioplankton, trophic status exerted significantly negative direct effects on bacterioplankton community composition and alpha diversity. To probe the response of bacterioplankton communities to trophic status in freshwater ecosystems in depth, Ji et al found that eutrophic lakes were dominated by Cyanobacteria, yet oligotrophic lakes were dominated by Actinobacteria in Wuhan, C hina[7]. A confusing problem relating to aquatic bacterioplankton ecology has not been clarified about which environmental factor plays a decisive role in shaping bacterioplankton c ommunities[5,9]

Methods

Results

Discussion

Conclusion