Fig. 3

Ratio of outflow to inflow concentrations of total and intact microbial cells in the three experimental setups, each repeated three times at monthly intervals. The y axis refers to log₁₀ (Cells _Outflow/Cells _Inflow), defined as the logarithmic ratio of outflow to inflow biomass as calculated from flow cytometry results and flowrate measurements. Flow cytometry measurements involve biological and technical triplicates for each time point. Green diamonds and blue circles represent intact and total cell concentration, respectively. Error bars indicate standard deviations. (A,D,G) Refers to the three monthly repeats of experiment, laminar flow conditions on pipes 3, 2 and 1 connected in series, CWS_slow sampled at locations outlet 3 and outlet 1, respectively every 38 min; (B,E,H) refers to the three monthly repeats of experiment under fast flow conditions, CWS_fast performed on pipes 3, 2 and 1 connected in series but sampled from outlet 1 only; (C,F,I) refers to the three monthly repeats of experiment under fast flow conditions, IWS_fast performed on pipes 4, 5 and 6 connected in series but sampled from outlet 6 only.