Motility and transport of microalgae in structured environments

Motile microorganisms are a paradigmatic example of soft active matter living in environments with complex spatio-temporal patterns. These patterns modify microbial motility through a combination of physical effects and biological sensing, which determine microbial fitness and therefore large-scale population dynamics. At the same time, the ability to structure the environment provides avenues to tune motility and elicit a predictable micro-to-mesoscopic behaviour.

In this talk I will review our research in this area, focussed on the model microalga Chlamydomonas reinhardtii. Moving up from individual cells to collectives, I will present some examples of how confinement and/or light stimuli can be used to modify motility. These experiments highlight the importance of a truly interdisciplinary understanding of microbial motility, which will need to integrate biological responses into physical models of microbial motility.