
From soil bacteria to sperm swimming in the fallopian tubes, microorganisms are often found to swim within confined environments. What is the effect of confinement on their flow fields? In a new paper, recently published in Physical Review Letters, we combine experiment and modelling to show that -contrary to expectations- the variety of microbial flow fields is greatly increased under confinement. This can in turn have have qualitative effects on both the biology (e.g., feeding currents) and the physics (e.g., collective behaviour) of microorganisms in confinement. This work was done in collaboration with Raphael Jeanneret and Mitya Pushkin.