Movie: Biomass-based model biofilm (apart)
Movie of a biofilm growing from 10 cells per species at time zero for 30,000 min (3 weeks), with one frame per 1,000 min. All frames were rendered with POV-Ray, showing each biomass brick as a sphere. The biomass of the ammonia oxidisers ("Nitroso") is green; the biomass of the nitrite oxidisers ("Nitro") is red. The grey box at the bottom is the inert substratum. Note the wrapped around boundaries in the horizontal direction. Scale: total width of the system = 200 µm.
This Biomass-based model version (apart) does not allow the coexistence of biomasses of the two species in the same grid element. The nitrite oxidisers grew only poorly because the ammonia oxidisers have a kinetic advantage under oxygen limitation. Oxygen limitation results from the high concentration of ammonia and nitrite in the bulk liquid.