On the diffusion of a plankton patch in a turbulent ocean

The horizontal dynamics of a single plankton "patch" in an ocean is conside red theoretically in terms of turbulent diffusion;equation taking into acco unt the scale-dependence of turbulent diffusivity. To describe local multip lication of the plankton community, the equation is provided with a nonline ar term. Both one-dimensional (diffusion of a strip) and two-dimensional (d iffusion of a circle) problems are considered. For both cases explicit form ulas for the size of the patch vs time are obtained.