Keywords: stirring, mixing, biomixing, Brownian motion.
Abstract: As fish or other bodies move through a fluid, they stir their
surroundings. This can be beneficial to some fish, since the plankton
they eat depends on a well-stirred medium to feed on nutrients.
Bacterial colonies also stir their environment, and this is even more
crucial for them since at small scales there is no turbulence to help
mixing. It has even been suggested that the total biomass in the