Core-satellite populations and seasonality of water meter biofilms in a metropolitan drinking water distribution system

Abstract

Drinking water distribution systems (DWDSs) harbor the microorganisms in biofilms and suspended communities, yet the diversity and spatiotemporal distribution have been studied mainly in the suspended communities. This study examined the diversity of biofilms in an urban DWDS, its relationship with suspended communities and its dynamics. The studied DWDS in Urbana, Illinois received conventionally treated and disinfected water sourced from the groundwater. Over a 2-year span, biomass were sampled from household water meters (n = 213) and tap water (n = 20) to represent biofilm and suspended communities, respectively. A positive correlation between operational taxonomic unit (OTU) abundance and occupancy was observed. Examined under a 'core-satellite' model, the biofilm community comprised 31 core populations that encompassed 76.7% of total 16 S rRNA gene pyrosequences. The biofilm communities shared with the suspended community highly abundant and prevalent OTUs, which related to methano-/methylotrophs (i.e., Methylophilaceae and Methylococcaceae) and aerobic heterotrophs (Sphingomonadaceae and Comamonadaceae), yet differed by specific core populations and lower diversity and evenness. Multivariate tests indicated seasonality as the main contributor to community structure variation. This pattern was resilient to annual change and correlated to the cyclic fluctuations of core populations. The findings of a distinctive biofilm community assemblage and methano-/methyltrophic primary production provide critical insights for developing more targeted water quality monitoring programs and treatment strategies for groundwater-sourced drinking water systems.

Impact of drinking water treatment and distribution on the microbiome continuum: an ecological disturbance's perspective

“…Methylotenera , Methylocystis and Hyphomicrobium are methylotrophs often found together with methanotrophs in enrichment cultures, possibly feeding on methane‐derived single‐carbon compounds generated by methanotrophs (Oshkin et al ., ). The dominance of these methano‐/methylotrophs in the studied distribution system was detailed in our previous report (Ling et al ., ). It is likely that methanotrophs acted as a primary producer in the distribution system to supply by‐products and metabolites derived from methane oxidation processes to methylotrophs and other heterotrophs.…”

“…So far, our knowledge on the ecology of microbial communities inside most of the drinking water systems around the world is very limited. Previous studies have elucidated the most basic ecological questions ‘who is there?’ and ‘how do they change over time and across space?’ in selected stages (i.e., mostly filters and distribution systems) of the drinking water treatment systems in a handful of cities (Hwang et al ., ; Pinto et al ., ; Zeng et al ., ; Pinto et al ., ; Gulay et al ., ; Ling et al ., ). These studies, however, could not provide a comprehensive view on how a microbiome continuum is impacted by disturbances at different stages.…”

“…and 'how do they change over time and across space?' in selected stages (i.e., mostly filters and distribution systems) of the drinking water treatment systems in a handful of cities (Hwang et al, 2012;Pinto et al, 2012;Zeng et al, 2013;Pinto et al, 2014;Gulay et al, 2016;Ling et al, 2016). These studies, however, could not provide a comprehensive view on how a microbiome continuum is impacted by disturbances at different stages.…”

Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant

“…Applied and Environmental Microbiology bacteria of other genera predominated in water meter biofilms at a groundwater supply distributing chlorinated drinking water (60). Their prevalence was attributed to the presence of methane in the finished water.…”

“…These bacteria grew slowly on charcoal yeast extract agar, but most of their physiological properties are still unclear. Reyranella massiliensis has been isolated by amoebal coculture with Acanthamoeba polyphaga (67) and was also observed in a biofilm on Norprene tubing exposed to drinking water (60). The colony counts of the biofilm were predominated by B. japonicum (Table S4), a slowly growing nitrogen-fixing bacterium and a root nodule microsymbiont of soybean (68).…”