Eco-hydrology in the transitional environment

On the basis of the European Water Framework Directive (WFD, 2000/60 EC), the quality status of transitional environments (estuaries, lagoons and coastal areas) is mainly established by the analysis of biological communities (benthos and plankton). However, both the structure and composition of biocenoses are strongly influenced by hydro-geological driving forces. In particular, the hydrodynamics induce land-sea gradients thus directly affecting biodiversity. The study of the relationship between abiotic driving forces and biological communities is used to differentiate signals due to natural variations from human-induced ones, being therefore important for the science of bioindication. Eco-hydrology is the study of the biota in relation to the effects of the hydro-geological driving forces.

This recent discipline is developed with respect to different space and temporal scales, and requires a multiple approach among ecology, hydrology and sediment studies. The research is supported by field measurements, in order to acquire data on water circulation, matter transport and chemical fluxes. GIS tools are used for the data treatment and interpretation, in particular to define spatially explicit scenarios. Conceptual as well as numerical models are implemented, in order to integrate measurements and to estimate non-directly-measurable parameters (such as residence time and confinement), providing a link among different disciplines for the study of complex systems.

Right image:

Sea-water renewal time is one of the main factors affecting the distribution of biological communities in lagoons. Moving landward from the sea  an increasing divergence from marine conditions is tolerated by progressively fewer, adapted  species.

In this picture water residence time is reported in the vertical (z) axis. High residence  time zones are depicted as mountain tips were few adapted species  can survive whereas well-flushed zones are green valleys where a flourishing biocoenosis can thrive.

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