Assessment of microbial community dynamics in river bank filtrate using high-throughput sequencing and flow cytometry

Measurements were made to establish cell counts of river bank filtrates (6 different wells in close adjacency) at different dates within a period of 3 months. Cell counts were further used to create estimated absolute abundances of microbial community compositions on the basis of a high-throughput-sequencing analysis made on the same dates.
Conclusion:
Measurements clearly indicated vast changes of the "microbial status" (increase of total cell counts) for some of the wells at the end of measurement period. The combination with high-throughput-sequencing data of the same samples provides valuable insights into absolute changes of taxon abundances, which could not have been detected with sequencing data only (as only relative abundances are provided). All measurements were performed as triplicates (of which only the "average" dataset according to total cell counts is provided here). Coefficient of variation of total cell counts among triplicates was always less than 5%. Measurements of validation beads (Spherotech) were performed at least on a weekly basis to ensure signal stability of fluorescence detection.