Fig. 2: Schematic overview of the experimental design.

a Undisturbed communities (U) received medium continuously at a dilution rate of 1 day⁻¹. b Disturbed communities (D) were 50-fold diluted with medium every second day. The dilution acted as a disturbance because the community’s biomass was reduced substantially, and resources were introduced as a large pulse. c Simulated logistic growth of the microbial communities’ biomass given the disturbance regime and carrying capacity (parameters: µ = 2.5 day⁻¹, continuous dilution = 1 day⁻¹ or semi-continuous 1:50 dilution every 2nd day). High carrying capacity is indicated as a solid black line, whereas low carrying capacity is presented as a dashed black line. When the communities are undisturbed, the biomass is expected to be at or near carrying capacity. The disturbance by dilution lowered the community’s biomass by a factor of 50, bringing the community considerably below the carrying capacity, resulting in close to exponential growth between dilutions. Triplicate microcosms were operated over 50 days for each experimental condition, and the disturbance regime was switched after 28 days. The groups are abbreviated as UDH, UDL, DUH, and DUL, in which the first letter indicates the disturbance regime in period 1 (day 1–28), the second the disturbance regime in period 2 (day 29–50) and the third letter the carrying capacity of the media (high or low).