Temporal and spatial variations in the bacterial community composition in Lake Bosten, a large, brackish lake in China

Lei Zhang,Pengfei Qi,Tingting Zhao,Li Li,Yu Cheng,Tingting Shen

doi:10.1038/s41598-019-57238-5

Abstract

The bacteria inhabiting brackish lake environments in arid or semi-arid regions have not been thoroughly identified. In this study, the 454 pyrosequencing method was used to study the sedimentary bacterial community composition (BCC) and diversity in Lake Bosten, which is located in the arid regions of northwestern China. A total of 210,233 high-quality sequence reads and 8,427 operational taxonomic units (OTUs) were successfully obtained from 20 selected sediment samples. The samples were quantitatively dominated by members of Proteobacteria (34.1% ± 11.0%), Firmicutes (21.8% ± 21.9%) and Chloroflexi (13.8% ± 5.2%), which accounted for more than 69% of the bacterial sequences. The results showed that (i) Lake Bosten had significant spatial heterogeneity, and TOC(total organic carbon), TN(total nitrogen) and TP(total phosphorus) were the most important contributors to bacterial diversity; (ii) there was lower taxonomic richness in Lake Bosten, which is located in an arid region, than in reference lakes in eutrophic floodplains and marine systems; and (iii) there was a low percentage of dominant species in the BCC and a high percentage of unidentified bacteria. Our data help to better describe the diversity and distribution of bacterial communities in contaminated brackish lakes in arid regions and how microbes respond to environmental changes in these stable inland waters in arid or semi-arid regions.

Highlights

The bacteria inhabiting brackish lake environments in arid or semi-arid regions have not been thoroughly identified
The contents of TD, total phosphorus (TP) and total organic carbon (TOC) in the Huangshuigou and macrophyte-dominated area were higher in winter than in summer (Fig. S1), which may be because the continuous low temperature in winter inhibits microbial activity and reduces the effect of microorganisms on the removal of nitrogen and phosphorus[24]
We found that the bacterial community of Lake Bosten sediments is spatially specific

Summary

Introduction

The bacteria inhabiting brackish lake environments in arid or semi-arid regions have not been thoroughly identified. Microorganisms are some of the most important factors in the nutrient cycling and decomposition of organic matter in lake sediments[2], and bacteria are thought to be a sensitive sentinel of those environmental changes[3]. Arid and semi-arid regions account for almost one-third of the world’s land area[6], and lakes in these areas provide sparse but valuable water resources for fragile environments and humans. We used high-throughput sequencing technology and redundancy analysis to explore the association between spatial-temporal changes in Lake Bosten bacterial communities and environmental factors. The research objectives are to identify (1) Whether there is spatial-temporal heterogeneity in the bacterial communities of lake sediments under the dual effects of eutrophication and salinity and (2) Which environmental factors control the assembly of bacterial communities in the sediments of Lake Bosten

Methods

Results

Discussion

Conclusion