Estuarine and lagoon biodiversity and their natural goods and services

Assessing and monitoring ecosystem quality status and service provision of aquatic ecosystems is an increasingly important area of scientific, socio-economical and political interest. Contributions from two related meetings organized by the Estuarine & Coastal Sciences Association (ECSA) and the Euro-Mediterranean Lagoon Federation (EUROMEDLAG) address this area of interest in estuaries and lagoons, dominant types of transitional waters, by an integration of holistic and reductionistic approaches. In this context, we synthesise the key points raised by the contributions given at the two meetings to emphasise that transitional waters have emergent properties, which support their classification as an aquatic realm different from both freshwater and marine ones. They provide crucial ecosystem services, such as food provision and support for nutrient cycling, whose value and underlying mechanisms have been addressed with particular reference to estuarine ecosystems. The experimental studies show the mechanistic relationships and the responses of ecosystem functions and biodiversity to contrasting/changing environmental conditions with human activities as key drivers affecting both biodiversity conservation and ecosystem service provision.