Fig. 4.

Competition between EPS⁺ and EPS^– cells within biofilms and for access to new resource patches. (A) The frequency of the EPS⁺ strain within biofilms is plotted as a function of time. Error bars denote SD (n = 3). (B) Weak disturbance: effluent from chambers containing growing biofilms was diverted to new chambers at 20 h and 46 h. The biovolumes of EPS⁺ cells (white bars) and EPS^– cells (black bars) in the newly formed monolayers are shown for both time points. (C) Severe disturbance: flow velocity through biofilm chambers was increased 1,000-fold at 20 and 46 h in separate replicates, and the effluent was used to colonize new chambers as in B.