Here, we focus on pattern formation in the wadden sediment (BioGeoChemistry of Tidal Flats) with models capturing the non-linear dynamics of tidal flats (pattern formation, complexity, and critical transitions).

The sediment of tidal flats is a subsystem of the marine environment where important processes take place: detritus accumulated in the water column sinks to the ground and is decomposed into biochemical compounds which - by microorganisms - are degraded in the sediment.

We focus on models describing these biochemical reactions and their interaction with physical transport processes (diffusion, advection). These models are highly non-linear and exhibit complex dynamics. It is the aim of this sub-project to study the variety of these dynamics.

We show that even simple models including the degradation of one compound by one population of microorganisms can exhibit a complex dynamical behaviour. In particular, we obtain phenomena of pattern formation, that means a spontaneous, discontinuous formation of new structures is taking place.

We show that the geometry of these structures can be stationary or transient and that in the latter case the dynamics have to be regarded as chaotical.
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