Microbial Quality and Phylogenetic Diversity of Fresh Rainwater and Tropical Freshwater Reservoir

Abstract

The impact of rainwater on the microbial quality of a tropical freshwater reservoir through atmospheric wet deposition of microorganisms was studied for the first time. Reservoir water samples were collected at four different sampling points and rainwater samples were collected in the immediate vicinity of the reservoir sites for a period of four months (January to April, 2012) during the Northeast monsoon period. Microbial quality of all fresh rainwater and reservoir water samples was assessed based on the counts for the microbial indicators: Escherichia coli (E. coli), total coliforms, and Enterococci along with total heterotrophic plate counts (HPC). The taxonomic richness and phylogenetic relationship of the freshwater reservoir with those of the fresh rainwater were also assessed using 16 S rRNA gene clone library construction. The levels of E. coli were found to be in the range of 0 CFU/100 mL – 75 CFU/100 mL for the rainwater, and were 10–94 CFU/100 mL for the reservoir water. The sampling sites that were influenced by highway traffic emissions showed the maximum counts for all the bacterial indicators assessed. There was no significant increase in the bacterial abundances observed in the reservoir water immediately following rainfall. However, the composite fresh rainwater and reservoir water samples exhibited broad phylogenetic diversity, including sequences representing Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, Lentisphaerae and Bacteriodetes. Members of the Betaproteobacteria group were the most dominant in both fresh rainwater and reservoir water, followed by Alphaproteobacteria, Sphingobacteria, Actinobacteria and Gammaproteobacteria.

Rapid and Stable Microbial Community Assembly in the Headwaters of a Third-Order Stream

“…During the 2017 sampling period of headwater sites, a storm event resulting in 2.54 cm of rainfall occurred. Rainfall was previously shown to introduce taxa into freshwater systems and increase diversity (22,29,30). While our results are consistent with this, it is interesting that each of the three sites sampled appeared to be affected differently by the influx of rainwater.…”

Chemical Composition and Bacterial Community in Size-Resolved Cloud Water at the Summit of Mt. Tai, China

“…We compared the bacterial phyla identified in this study with those in previous studies. These five phyla were also found in aerosol particles (Bowers et al, 2016) and other aquatic samples, such as lake water samples (Zeng et al, 2014), rain water samples (Evans et al, 2009;Kaushik et al, 2013;Peter et al, 2014) and river water samples (Kovatch and Schultz, 2013). But in the different kinds of samples, the dominant bacteria phylum was diverse and the relative abundance of the same bacteria phylum differed greatly (Table S4).…”

A review on physicochemical and microbiological contamination of roof-harvested rainwater in urban areas

“…Ahmed et al (2010a,b) also assessed the convenience of analyzing fecal indicator bacteria (E. coli, enterococci, and Clostridium perfringens) to predict the presence or absence of pathogens in rainwater, concluding that no significant correlation was found between the concentration of fecal indicators and pathogenic microorganisms. (Kaushik et al, 2014) assessed the microbial quality of rainwater using as microbial indicators: E. coli, total coliforms, and enterococci along with total heterotrophic plate counts (HPC). This study obtained levels of E. coli in rainwater within the range of 0-75 CFU/100 mL for a highly urbanized site with tropical climate (Singapore), concluding that despite the presence of microbial pathogens, rainwater harvesting in large water catchment areas is a promising freshwater resource following treatment.…”