Figure 2.

Population dynamics of biofilm-dwelling bacteria and phages for several example cases. For each example simulation, bacterial biomass is plotted in the thick dotted line (left axis), and phage counts are plotted in the thin solid line (right axis). (a) Biofilm death: phages rapidly proliferate, and bacterial growth cannot compensate, resulting in clearance of the biofilm population (and halted phage proliferation thereafter). (b) Coexistence of bacteria and phages. We found two broad patterns of coexistence, one in which bacteria and phage populations remained at relative fixed population size (green lines), and one in which bacterial and phage populations oscillated as large biofilms clusters grew, sloughed and re-grew repeatedly over time (black lines). (c) Phage extinction and biofilm survival. In many cases, we found that phage populations extinguished while biofilms were relatively small, allowing the small population of remaining bacteria to grow unobstructed thereafter. Some of these cases involved phage population oscillations of large amplitude (black lines), while others did not (green lines).