Ecomorphology of soft-bottom estuaries and tidal lagoons

Ciclo de Seminarios del Departamento de Recursos Naturales

Due to the many functions estuaries fulfill (sustainable) management of these areas, like the Westerschelde (SW Netherlands), is very complex. Modelling of influences exerted by biota can enhance predictive power of sedimentation-erosion models and support sustainable management.
Sediment composition and behaviour cannot be predicted by abiotic models alone… Aside from the intrinsic physico-chemical properties, tidal flat sedimentology is also determined by biota in and on the sediment. Both flora and fauna do not passively undergo physico-chemical stress exerted by the environment but act to reduce the net effect of the stress. These active benthos-sediment interactions are known as ‘ecosystem engineering’. Biota can shape their immediate environment to their advantage.
Ecosystem engineering has its spatial consequences: Diatoms favour finer sediments. Diatom mats can trap finer particles creating their own favoured environment thereby increasing the percentage of fines locally. Both sediment composition and transport are altered in this way.
Burrowing infauna can transport sediment between the surface and deeper layers. Several species segregate mud and sand actively. They can do this by e.g. feeding selectively or by their burrowing activities. Again, sediment properties are actively altered by organisms.
This study aims to identify, and ultimately, quantify relations between biological and erosion-accretion processes in order to use them in predicitve models used for management purposes.