Long-Term Succession of Structure and Diversity of a Biofilm Formed in a Model Drinking Water Distribution System

Abstract

In this study, we examined the long-term development of the overall structural morphology and community composition of a biofilm formed in a model drinking water distribution system with biofilms from 1 day to 3 years old. Visualization and subsequent quantification showed how the biofilm developed from an initial attachment of single cells through the formation of independent microcolonies reaching 30 m in thickness to a final looser structure with an average thickness of 14.1 m and covering 76% of the surface. An analysis of the community composition by use of terminal restriction fragment length polymorphisms showed a correlation between the population profile and the age of the sample, separating the samples into young (1 to 94 days) and old (571 to 1,093 days) biofilms, whereas a limited spatial variation in the biofilm was observed. A more detailed analysis with cloning and sequencing of 16S rRNA fragments illustrated how a wide variety of cells recruited from the bulk water initially attached and resulted in a species richness comparable to that in the water phase. This step was followed by the growth of a bacterium which was related to Nitrospira, which constituted 78% of the community by day 256, and which resulted in a reduction in the overall richness. After 500 days, the biofilm entered a stable population state, which was characterized by a greater richness of bacteria, including Nitrospira, Planctomyces, Acidobacterium, and Pseudomonas. The combination of different techniques illustrated the successional formation of a biofilm during a 3-year period in this model drinking water distribution system.

Heterotrophic Pioneers Facilitate Phototrophic Biofilm Development

“…Early colonizers might change the environmental conditions in the biofilm, e.g., by altering the substratum surface [16,18], and hence facilitating the attachment of filamentous cyanobacteria.…”

“…Successional community changes during the colonization of new habitats or after environmental disturbances have been described for communities of planktonic and benthic microalgae [12,24], and more recently in bacterial communities [9,14,18]. Primary succesional development of an ecosystem is always initiated by the settlement of pioneer organisms in a previously uncolonized environment.…”

Pyrosequencing analysis of eukaryotic and bacterial communities in faucet biofilms

“…DWDS bacterial community can be influenced by chlorine levels, concentration of organic compounds, water temperature, and physicochemical characteristics of pipe materials (Niquette et al, 2001). In addition, the occurrence of bacterial community succession was observed in a model DWDS (Martiny et al, 2003), demonstrating a long-term development of biofilm formation in DWDSs.…”

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

“…However, valuable information has been obtained from the laboratory or pilot reactors that simulate DWDSs. Examining community dynamics in an oligotrophic, disinfectant-free model system revealed that biofilm development on surfaces in contact with drinking water is slow and involves community succession over a multiyear span (Martiny et al, 2003). This study highlights the need for temporal replication for DWDS biofilm studies.…”