Various recent studies have revealed amazing phenomena in the dynamics of bacterial colonies where biology meets physics, in particular statistical physics, fluid dynamics, and (soft) con- densed matter. These biological systems reveal analogies with complex fluids (isotropic- nematic phase transitions), spinodal decomposition phenomena in physics and materials sci- ence, and diffusion-limited reaction kinetics in chemistry. Moreover, gene segregation phe- nomena can be studied with tools from statistical physics (e.g., Potts-like models).
Life on Earth is invariably associated with (flowing) water. Fluid flows determine the fate of bacterial colonies and supply nutrients. Many studies focused on population dynamics in absence of fluid motion, e.g. bacteria living on a Petri dish or in a well-mixed medium. The life of plankton and cyanobacteria in oceans and lakes, however, is ruled by fluid transport, compressibility effects and particle-number fluctuations. Thus we face fundamental questions of how fluid mechanics and turbulence will affect the dynamics of bacterial colonies and their genetic evolution.