Stable-isotope probing and metagenomics reveal predation by protozoa drives E. coli removal in slow sand filters.

ABSTRACT: Stable-isotope probing and metagenomics were applied to study samples taken from laboratory-scale slow sand filters 0.5, 1, 2, 3 and 4 h after challenging with (13)C-labelled Escherichia coli to determine the mechanisms and organisms responsible for coliform removal. Before spiking, the filters had been continuously operated for 7 weeks using water from the River Kelvin, Glasgow as their influent source. Direct counts and quantitative PCR assays revealed a clear predator-prey response between protozoa and E. coli. The importance of top-down trophic-interactions was confirmed by metagenomic analysis, identifying several protozoan and viral species connected to E. coli attrition, with protozoan grazing responsible for the majority of the removal. In addition to top-down mechanisms, indirect

SUBMITTER: Haig SJ 

PROVIDER: S-EPMC4817707 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature