Development of viable single-species and dual-species biofilms over 96 h. Following inoculation with early-stationary-phase cells, biofilms were visualized by CLSM every 24 h. Flow cells were inoculated with S. natatoria 2.1gfp (A), S. natatoria 2.1COGgfp (B), M. luteus 2.13 (C), S. natatoria 2.1gfp and M. luteus 2.13 (D), and S. natatoria 2.1COGgfp and M. luteus 2.13 (E) cells. S. natatoria cells are green, and M. luteus cells are red. Dimensions of the regions shown are 230 μm by 230 μm. Bars, 50 μm.