From October 1 2010 through May 30 2011 I worked with Professor Ana Carpio at Universidad Complutense de Madrid, Spain, and her doctoral student David Rodriguez. I worked on developing and programming (in Fortran) a cellular automata model for biofilm growth. The work was made possible by an UCM-EEA Abel Grant, for which I am very grateful.
The model we used is based on that of Hermanowicz (2001), where bacteria grow in a rectangular tube. We added features to that model, and modeled the flow of water.
Here are movies of our simulation. The first one forms streamers (fingers), and the second one has a more uniform layer.
The flow is coming in from the left and carries suspended cells:
We later extended the model to three dimensions. Note that part which are not connected to the substratum break off and get carried away with the flow.