title: Impact of Treated Sewage Effluent on the Microbiology of a Small Brook Using Flow Cytometry as a Diagnostic Tool.
abstract: Flow cytometry was applied to assess the microbiological impact of treated sewage effluent discharge into a small brook carrying surface runoff water. Increases in dissolved organic carbon and soluble reactive phosphorous were accompanied by increases in counts of intact bacteria by up to eightfold. Effluent ingress furthermore resulted in a pronounced shift of bacterial clusters. Whereas brook water upstream of the discharge point was characterised by a bacterial cluster with low nucleic acid (LNA) content, downstream water showed a shift to bacteria with high nucleic acid (HNA) content. Changes in the LNA/HNA ratio were largely maintained along the course of the brook. Results suggest that the LNA/HNA ratio can under certain conditions serve as an indicator of anthropogenic nutrient impact. Measuring impact on this low trophic level might be more sensitive and straightforward than measuring macroindicators. More evidence will however be required to assess the usefulness of LNA/HNA measurements to assess the ecological nutrient status of natural waters and the impact of nutrient pollution.
authors: School of Energy, Environment and Agrifood, Cranfield University, Cranfield, MK43 0AL UK.
authors: Ibiye S K
authors: IS
authors: Harry
authors: School of Energy, Environment and Agrifood, Cranfield University, Cranfield, MK43 0AL UK.
authors: Ekwu
authors: E
authors: Ameh
authors: School of Energy, Environment and Agrifood, Cranfield University, Cranfield, MK43 0AL UK.
authors: Frederic
authors: F
authors: Coulon
authors: School of Energy, Environment and Agrifood, Cranfield University, Cranfield, MK43 0AL UK.
authors: Andreas
authors: A
authors: Nocker
keywords: Flow cytometry; High nucleic acid bacteria; Low nucleic acid bacteria; Microbiological water quality; Phosphate; Wastewater effluent; Water ecology