Abstract

The observed filamental nature of plankton populations suggests that stirring plays an important role in determining their spatial structure. Considering a flow where the fluid parcel trajectories are chaotic, and neglecting diffusion, the concentrations of different biological species within a fluid parcel are then determined by its time history.

The induced spatial structure has been shown to be a result of competition between the rate of convergence of the biological processes involved and the rate of divergence of the distance of neighbouring fluid parcels. It has also been argued (except under rather special conditions), that the small scale behaviour should be the same for all interacting species (Neufeld et al. 1999). However, Abraham et al. (1998), by introducing a biologically more relevant maturation time into the evolution equations, presented results that show different small-scale spatial structures for different species (specifically different structures for zooplankton and phytoplankton).

This talk will present both theoretical and numerical results explaing the effect of a maturation time on the scaling behaviour of biologically active species, such as plankton, advected by a chaotic flow.

Alexandra’s home page