Variations in abundance and community composition of denitrifying bacteria during a cyanobacterial bloom in a eutrophic shallow lake in China

Weiguo Zhang,Yan Gao,Neng Yi,Chengcheng Wang,Panpan Di,Shaohua Yan

doi:10.1080/02705060.2017.1323681

Weiguo Zhang, Yan Gao + Show 4 more

Open Access

https://doi.org/10.1080/02705060.2017.1323681

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Abstract

ABSTRACTAlthough cyanobacterial blooms can change microbial communities, it is still unclear what impact such harmful blooms will have on denitrifying bacteria, the drivers of the removal of excessive nitrogen from water. In order to clarify the impact, populations of denitrifying bacteria, with periodic proliferation and dominance of cyanobacteria in a eutrophic shallow lake located in southeast China, were investigated using quantitative real-time polymerase chain reaction (qPCR) and 454-pyrosequencing based on the copper-containing nitrite reductase (nirK) gene, cytochrome cd1-containing nitrite reductase (nirS) gene and nitrous oxide reductase (nosZ) gene. Samples were collected periodically during a three-month period when the cyanobacterial density gradually increased. In the qPCR analyses, abundances of nirK, nirS and nosZ were intensely positively correlated with the biomass of cyanobacteria. Moreover, 454-pyrosequencing revealed that the community composition of denitrifying bacteria shifted with the increase in cyanobacterial density. These results indicated that the shifts of the community composition of denitrifying bacteria might be related to cyanobacterial blooms, which could potentially lead to alterations of denitrification in eutrophic water.

Highlights

Excessive nitrogen and phosphorus input associated with urban, agricultural and industrial development have accelerated the rate of eutrophication
In order to clarify the impact, populations of denitrifying bacteria, with periodic proliferation and dominance of cyanobacteria in a eutrophic shallow lake located in southeast China, were investigated using quantitative real-time polymerase chain reaction and 454pyrosequencing based on the copper-containing nitrite reductase gene, cytochrome cd1-containing nitrite reductase gene and nitrous oxide reductase gene
These results indicated that the shifts of the community composition of denitrifying bacteria might be related to cyanobacterial blooms, which could potentially lead to alterations of denitrification in eutrophic water

Summary

Introduction

Excessive nitrogen and phosphorus input associated with urban, agricultural and industrial development have accelerated the rate of eutrophication. This accelerated rate favors the periodic proliferation and dominance of cyanobacteria in various aquatic ecosystems (Eiler & Bertilsson 2004; Dziallas & Grossart 2011), posing a great threat to the sustainability of water quality and ecology (Paerl & Huisman 2009). China has the largest subtropical lake density in the Northern Hemisphere (Downing et al 2006). All together there are 698 subtropical shallow lakes (>1 km2) in China, mainly located along the Yangtze River (Yang et al 2010).

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