EWRE Seminar

Start Date: 
Friday, November 18, 2016 - 3:00pm to 4:00pm

1311 EECS

Presenter: 
Frederik Hammes, Drinking Water Microbiology Group, Swiss Federal Institute of Aquatic Science & Technology (Eawag), Switzerland
Caitlin Proctor, Drinking Water Microbiology Group, Swiss Federal Institute of Aquatic Science & Technology (Eawag), Switzerland

High Resolution Flow Cytometric Monitoring of Microbial Dynamics in Engineered Aquatic Ecosystems

Accurate monitoring of microbial dynamics in engineered and environmental aquatic ecosystems is critical

 for a better understanding of the causes and consequences of microbiological fluctuations. However, the common

 practice of infrequent grab-sampling and measurements with outdated methodology hampers sensible

 characterization – and thus understanding – of such dynamics. In this presentation we will discuss new flow

 cytometric approaches to characterize temporal fluctuations in the microbial communities of drinking water systems

 from source to tap. In a first example, we tracked microbiological changes in a Dutch drinking water system bi-

weekly during 2 years, demonstrating dramatic seasonal fluctuations in bacterial cell concentrations, partially

 governed by changes in water temperature. In a second example, we implemented newly developed fully automated

 online flow cytometry tools to monitor changes in groundwater aquifers used for drinking water at 15 minute

 resolution during multiple weeks. With these large data sets we could accurately describe and quantify both natural

 events (e.g., rainfall) and man-made events (e.g., water extraction), which influenced the microbial dynamics and

 which would be missed by grab sampling. As a last example, we show newly-developed real-time flow cytometry

 technology to measure changes in bacterial concentrations in millisecond resolution. We used this to characterize

 microbial dynamics during contamination and shock chlorination events, as well as the detachment of bacteria from

 shower-hose biofilms during shower events. These examples demonstrate the need for, and progress towards,

 automated online microbiological monitoring technologies.

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