The impact of physico-chemical water quality parameters on bacterial diversity in the Vaal River, South Africa

Abstract

This study aimed to identify bacterial community structures in the Vaal River using PCR-DGGE (polymerase chain reaction denaturing gradient gel electrophoresis) and high-throughput sequencing. The impact of physico-chemical characteristics on bacterial structures was investigated through multivariate analysis. Samples were collected from 4 sampling stations along the Upper Vaal River during winter (June 2009) and summer (December 2010). Physico-chemical analysis was conducted on-site. Additional physico-chemical data were obtained from statutory bodies. DNA was directly isolated from water samples and PCR amplified using universal bacterial primer pairs. PCR products were subjected to DGGE fingerprinting and high-throughput sequencing, followed by Shannon-Weaver diversity calculations, cluster analysis and multivariate analysis. Physico-chemical parameters did not exceed the prescribed South African water quality standards for domestic use, aquatic ecosystems, livestock watering and irrigation. DGGE banding patterns revealed similar bacterial community structures for 3 of the 4 sampling stations. PCA and RDA indicated that pH, water temperature and inorganic nutrient concentrations could be used to explain changes in bacterial community structures. High-throughput sequencing data showed that bacterial assemblages were dominated by common freshwater groups: Cyanobacteria, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes and Actinobacteria. Other freshwater phyla such as Deltaproteobacteria, Epsilonbacteria, Acidobacteria, Verrucomicrobia, Firmicutes, Fusobacteria, Flavobacteria and Fibrobacteres were found in low proportions. This study provides an overview of the dominant bacterial groups in the Upper Vaal River and the impact of environmental changes on bacterial diversity.

Investigating Industrial Effluent Impact on Municipal Wastewater Treatment Plant in Vaal, South Africa

“…The EC values for downstream and upstream and potable water samples ranged from 368 to 763 µS/cm (Table 5). These values are higher compared to those reported by Jordan and Bezuidenhout [48] for the Vaal River in 2012. This implies that the rate of pollution has increased over the years possibly because of increased anthropogenic influences.…”

16S rRNA gene based bacterial community structure of wastewater treatment plant effluents

“…The Shannon's diversity indexes (at phylum and family level) were higher in effluent samples collected in Autumn than those in Spring. The difference in bacterial diversity between different sampling locations depends on the physical and chemical variables which likely select for different bacterial types (Jordaan and Bezuidenhout 2013;Silva-Bedoya et al 2016).…”

Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility

“…As a consequence, genomic and physiological characterizations of Verrucomicrobia isolates have contributed to the knowledge of their biology and ecology (Isanapong et al 2012 ; Wertz et al 2012 ). However, most information on the ecology of Verrucomicrobia is revealed by the correlations of 16S rRNA gene abundance with environmental parameters, such as soil moisture and soil physicochemical factors (Buckley and Schmidt 2001 ; Jordaan and Bezuidenhout 2013 ; Pan et al 2014 ).…”