1210.8103 (D. A. Head)

Linear surface roughness growth and flow smoothening in a
three-dimensional biofilm model    [PDF]

D. A. Head

The sessile microbial communities known as biofilms exhibit different surface structures as environmental factors are varied, including nutrient availability and flow-generated shear stresses. Here we modify an established agent-based biofilm model to include adhesive interactions, permitting it to mechanically react to an imposed stress. This model is employed to analyse the growth of surface roughness of single-species, three-dimensional biofilms. We find linear growth laws of surface geometry in both horizontal and vertical directions, and an active surface layer whose thickness anti-correlates with roughness. Flow is consistently shown to reduce surface roughness without affecting the active layer. We argue that the rapid roughening is due to non-local surface interactions mediated by the nutrient field which are curtailed by sufficiently rapid flows, and suggest simplified models will need to be developed to elucidate the underlying mechanisms.

View original: http://arxiv.org/abs/1210.8103