Flow cytometry for microbial water quality evaluation - FLOMI
Funded by the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments (KIT Future Fields)
The main goal of our FLOMI project is to achieve a better understanding of the transport processes governing the spatial and temporal dynamics of fecal bacteria in karst aquifer systems, as a basis for a better management and protection of these valuable but vulnerable freshwater resources.
A flow cytometric approach to investigate microbiological indicators is emerging and very promising. This technique allows fast analyses of the total and intact cell count, depending on the applied staining protocol. The staining with SYBR Green allows to detect viable and dead cells which yield the total cell count (TCC). If this staining protocol is combined with the use of propidium iodide, it is possible to further distinguish between viable and dead cells. Furthermore, it is possible to distinguish between microorganisms with a low (predominant in groundwater) and a high nucleic acid content (predominant in surface water) (Figure 1). Recent studies showed that this technique is perfectly suited for karst systems which suffer from high bacteria concentrations during contamination events such as rainfall which require flexible sampling strategies.
The recently developed Flow Cytometry Automation Add-on overcomes the obstacle of manual sampling and delivers information on the microbial water quality within 15 minutes on-site, i.e. at the experimental field site. This approach will yield unique, high-quality data sets which can be used as benchmarks and means to refine water quality predictions.
Figure 1: Sampling location Sägebach spring and premliminary results for the total cell count and low and high nucleic acid contents.