The role of turbulent diffusion for copepods with feeding currents

Abstract

The encounter rate between predator and prey is frequently modeled in terms of the 'swept volume' associated with the relative velocity of the two organisms and an appropriate cross-sectional area. For the copepods which use feeding currents, an alternative conceptual model of the process is that the food particles are diffusing towards the predators. Their feeding currents trap the prey (even though they are well beyond the range of either visual or chemical detection) and entrain them towards their waiting arms. The predators thus benefit from the turbulent motion and diffusion, even though much of it is due to motions with scales significantly larger than their body's size. The feeding currents serve to dramatically increase the flux of food.