Universal biofilm height dynamics*

Bacterial colonies play important roles in ecology and medicine, as they are sources of infection and they account for a large percentage of biomass on Earth. However, fundamental questions remain about the nature and dynamics of the vertical growth of biofilms. Through interferometry, we can capture their height dynamics with nanometer precision. With this tool, we characterize their growth and show that current literature models do not capture the behavior of the system on short and long timescales.

Using a data focused approach we develop a simple model that takes in account the geometry of the system, and the fact that the interaction of the colony and the environment is limited through its interface. This interface-limited model, accurately fits the growth of multiple strains in a laboratory setting (e.g., E. coli, V. cholerae, Aeromonas, Bacillus, yeast) for the first 48 hours, and predicts the maximum height a colony reaches in the long time limit. While this interface-limited model accurately describes height dynamics across time scales, more experiments and analysis must be done to understand the limits in which it remains useful.