Comparison and Interpretation of Taxonomical Structure of Bacterial Communities in Two Types of Lakes on Yun-Gui plateau of China

Maozhen Han,Junqian Zhang,Zhi Wang,Chunyu Zhou,Kang Ning,Yanhai Gong

doi:10.1038/srep30616

Abstract

Bacterial communities from freshwater lakes are shaped by various factors such as nutrients, pH value, temperature, etc. Their compositions and relative abundances would undergo changes to adapt the changing environments, and in turn could affect the environments of freshwater lakes. Analyses of the freshwater lake’s bacterial communities under different environments would be of pivotal importance to monitor the condition of waterbody. In this study, we have collected freshwater samples from two lakes on Yun-Gui plateau of China, Lake Dianchi and Lake Haixihai, and analyzed the bacterial community structures from these samples based on 16S rRNA sequencing. Results have shown that: Firstly, the bacterial community of these samples have very different taxonomical structures, not only between two lakes but also among the intra-groups for samples collected from Dianchi. Secondly, the differences between samples from two lakes are highly associated with the chemical-geographical properties of the two lakes. Thirdly, for samples of Dianchi and Haixihai, analytical results of physicochemical, taxonomical structure and relative abundance of community revealed that extreme physicochemical factors caused by human activities have strongly affected the bacterial ecosystem in Dianchi. These results have clearly indicated the importance of combining biological profiling and chemical-geographical properties for monitoring Chinese plateau freshwater bacterial ecosystem, which could provide clues for Chinese freshwater ecosystem remediation on plateau.

Highlights

It is well-known that freshwater habitats, especially bacterial communities, play essential roles in global biogeochemical cycles
Samples from DC and HXH have shown strong variations in dissolved oxygen (DO), total nitrogen (TN), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), nitrite nitrogen (NO2−-N), total phosphorus (TP), orthophosphate (PO43−-P), suspended solids (SS), potassium permanganate index (CODMn) and chlorophyll a (Chl-a) (t-test for per characterization, all P < 0.05, the value of each physicochemical character was shown in Supplementary Table S1)
For intra-group samples from DC, TN (6.38–9.35 mg/L), TP (0.157–0.558 mg/L) and Chl-a (205.3–364.1 μg/L) in most of Caohai Lake (D-C) samples were all higher than what has been measured in Waihai Lake (D-W) (TN, 1.75–4.27 mg/L; TP, 0.096–0.205 mg/L; Chl-a, 57.2–148.6 μg/L), except DC7

Summary

Introduction

It is well-known that freshwater habitats, especially bacterial communities, play essential roles in global biogeochemical cycles. It is generally known that lakes could exist in two alternative stable states of oligotrophy (clear with abundant submerged macrophytes) and eutrophy (turbid with abundant algae) These two types of lakes have different geobiochemical characteristics[13]. HXH is a relatively non-polluted, macrophytic and oligotrophic freshwater lake, located on the Yun-Gui plateau, about 300 kilometers from DC These two lakes represent two types of lakes: DC is eutrophic, turbid with abundant algae; while HXH is oligotrophic, clear with abundant submerged plants. By comparing the structure of bacterial communities of these lakes, we could be able to better understand the mechanisms through which environmental factors could alter bacterial communities in the freshwater lakes, which may provide clues for eutrophic lake remediation

Methods

Results

Conclusion