Concerning marine environmental problems, the advection of biologically and chemically active substances in ocean flows is of great importance.
The aim of the project is the systematic analysis of the interactions between
populations and physical transport processes in marine environments. Transport
by means of chaotic advection was first studied with passive tracers and
extended to "active tracers". Active tracers are not only transported by the
flow, they are active in the sense that they can be characterized as being
actively involved in growth-, grasing-, competition- and extinction-processes.
We focus on pattern formation phenomena in the medium, which are favourable to
the growth of the biological populations.
The interaction between biological growth processes, diffusion, and chaotic
advection leads to patchiness and provides a possible mechanism for the
coexistence of competing species (the paradox of phytoplankton and biodiversity).
Since the time scale of the transport is usually much shorter than the
time-scale of the biological processes, these structures developing on
the invariant manifolds of the hydrodynamical system could be a means of
bridging the gap between the time-scales.
The focus also lies on the interaction between competition and chaotic advection
as promoters of biodiversity in marine eco-systems. Theoretical predictions are
compared with simulations using a three-dimensional model of the East Frisian Waddensea