Dresden 2014 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 46: Stochastic Dynamics of Growth Processes in Biological and Social Systems (joint session SOE/BP)

DY 46.9: Vortrag

Freitag, 4. April 2014, 12:00–12:15, GÖR 226

A Non-Equilibrium Phase Transition in a Biofilm Growth Model in a Fluctuating Environment — •Florentine Mayer and Erwin Frey — Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNs), Department of Physics, Ludwig-Maximilians-Universität München, Germany

Bacterial communities represent complex and dynamic ecological systems. They appear in the form of free-floating bacteria and biofilms in nearly all parts of our environment. They are highly relevant for human health and disease. Spatial patterns arise from heterogeneities of the underlying landscape or are self-organized by the bacterial interactions, and play an important role in maintaining species diversity. Bacteria must rapidly adapt to fluctuating environments in order to survive. In biofilms this is often achieved by phenotypic diversity, where bacteria can switch between different phenotypic states. Survival of the population can increase if each of these phenotypes is adapted to different environmental conditions.To analyze biofilm growth we set up a two-species automaton model in which growth, death and switching rates depend on the environmental conditions. These fluctuate, resulting in periodically interchanged reaction rates. Depending on the rates we find either fast extinction or thriving biofilms with intriguing spatio-temporal patterns. Close to the region of extinction patterns become self-affine, which is typical for a phase transition to an absorbing state. Employing extensive stochastic simulations we measure critical exponents of our non-equilibrium phase transition and find universal scaling behaviour characterising the universality class of our model.