Revealing Cryptic Changes of Cyanobacterial Community Structure in Two Eutrophic Lakes Using eDNA Sequencing.

Yongguang Jiang,Gaofei Song,Gongliang Yu,Peng Xiao,Renhui Li

doi:10.3390/ijerph17176356

Abstract

Harmful cyanobacterial blooms pose a risk to human health worldwide. To enhance understanding on the bloom-forming mechanism, the spatiotemporal changes in cyanobacterial diversity and composition in two eutrophic lakes (Erhai Lake and Lushui Reservoir) of China were investigated from 2010 to 2011 by high-throughput sequencing of environmental DNA. For each sample, 118 to 260 cpcBA-IGS operational taxonomic units (OTUs) were obtained. Fifty-two abundant OTUs were identified, which made up 95.2% of the total sequences and were clustered into nine cyanobacterial groups. Although the cyanobacterial communities of both lakes were mainly dominated by Microcystis, Erhai Lake had a higher cyanobacterial diversity. The abundance of mixed Nostocales species was lower than that of Microcystis, whereas Phormidium and Synechococcus were opportunistically dominant. The correlation between the occurrence frequency and relative abundance of OTUs was poorly fitted by the Sloan neutral model. Deterministic processes such as phosphorus availability were shown to have significant effects on the cyanobacterial community structure in Erhai Lake. In summary, the Microcystis-dominated cyanobacterial community was mainly affected by the deterministic process. Opportunistically dominant species have the potential to replace Microcystis and form blooms in eutrophic lakes, indicating the necessity to monitor these species for drinking water safety.

Highlights

Cyanobacterial blooms in eutrophic freshwater bodies are a globally severe environmental problem [1,2]
The results of this study revealed that the two eutrophic lakes have different cyanobacterial community structures, they both displayed Microcystis blooms
Results from the Sloan neutral model suggested that the assembly of cyanobacterial communities in the two eutrophic lakes was affected by both stochastic and deterministic processes, and the latter may play a more important role

Summary

Introduction

Cyanobacterial blooms in eutrophic freshwater bodies are a globally severe environmental problem [1,2]. The massive proliferation of cyanobacteria has increased the difficulty and cost of water management of urban water supplies [3]. Off-flavor compounds are released from both growing and decaying blooms, resulting in problems with undesirable odors in ambient air and drinking water [4,5]. The oxidation of large amounts of organic matter released from cyanobacterial cells may cause oxygen depletion, which is lethal to many aquatic animals such as fish [6]. Cyanobacterial blooms and their metabolites pose a great risk to the health of aquatic ecosystems and drinking water safety. It is important to monitor the dynamics of cyanobacterial communities in water bodies in order to manage cyanobacterial blooms in good time

Methods

Results

Discussion

Conclusion