Diel vertical migration is the daily movement of organisms to and from the surface in the ocean and lakes. It is perhaps the largest synchronous animal migration by total biomass. This poster pertains to the mixing effects of this migration.

The Squirmer model for flows created by low Reynolds number organisms is used to create simulations of vertically migrating swimmers entraining tracer particles. These tracer particles may represent nutrients or carbon and oxygen. Realistic swimmer motion involving a phototactic susceptibility variable is implemented. Many independent simulations are run, each involving randomly distributed swimmers displacing a tracer particle. The resultant vertical positions of the tracer particles are plotted against time, and a drift velocity is calculated.

Future work will involve implementation of run-and-tumble motion, negative buoyancy, and molecular scalar diffusion. Work might also be done to study other forms of biogenic mixing, including bioconvection, as well as turbulence created by high Reynolds number swimmers.