Principal Investigator Joern Dunkel
Bacteria and algae reach respectable swimming speeds of a few times their body length per second. Even more remarkably, ensembles of microorganisms exhibit complex collective behavior and can form coherent structures like turbulent vortices, spirals or bionematic jets. The characteristic length scales of these patterns may exceed the size of an individual organism by several orders in magnitude. Dynamical structure formation in bacterial systems emerges due to a combination of environmental factors (e.g., varying nutrient resources or oxygen gradients), biological competition, chemical communication (deposition and detection of messenger substances), and physical interactions. Part of our research focusses on identifying and understanding physical processes that may trigger collective dynamics in microbial suspensions. We are interested in questions such as: How do individual bacteria and microalgae affect their fluid environment? Which generic or specific mechanisms are responsible and/or necessary for the collective behavior of these microorganisms? What role did hydrodynamic effects play in the evolution from unicellular to multicellular forms of life? How can collective motions be suppressed or enhanced by external manipulation?