Selection of an indicator to assess a highly modified saline ecosystem.

The Water Framework Directive (WFD, 2000/60/EC) determines that all water bodies must achieve a good ecological status. The solar salterns system of Mata-Torrevieja (Spain) has been designated as Heavily Modified Water Bodies (HMWB). This ecosystem is a transitional water body (TW) largely conditioned by socio-economic management plan and the related human activities that take place. Thus, WFD establishes as obligatory the determination of their ecological potential, and not their ecological status. In order to define the ecological potential, it is necessary to determine previously the chemical and biological conditions of the water body. This paper is focused on the analysis of physical-chemical parameters of a saltern system during 2008-2016, in order to establish a starting point for the implementation process of the WFD in this type of ecosystem (TW-HMWB). The behavior of salinity and physical-chemical parameters (temperature, pH, nutrients) has been studied. Salinity was the most relevant parameter studied to define pressures for these water bodies. However, total phosphorus turned out to be a good potential status indicator. It would be one of the most suitable chemical parameters to propose a methodology for the determination of the ecological potential in the salterns.