  A stochastic model is used to assess the effect of external parameters on the
development of submerged biofilms on smooth and rough surfaces. The model
includes basic cellular mechanisms, such as division and spreading, together
with an elementary description of the interaction with the surrounding flow and
probabilistic rules for EPS matrix generation, cell decay and adhesion. Insight
on the interplay of competing mechanisms as the flow or the nutrient
concentration change is gained. Erosion and growth processes combined produce
biofilm structures moving downstream. A rich variety of patterns are generated:
shrinking biofilms, patches, ripple-like structures traveling downstream,
fingers, mounds, streamer-like patterns, flat layers, porous and dendritic
structures. The observed regimes depend on the carbon source and the type of
bacteria.
