Posidonia oceanica is an endemic Mediterranean seagrass used as a ‘biological quality element’ in monitoring programmes of the EU Water Framework Directive, providing information about coastal ecosystems status. The regression of P. oceanica meadows caused a growing interest among policy makers to assess the value of seagrasses and to increase their protection. An evaluation of P. oceanica meadows located in the Ligurian-Provençal basin (NW Mediterranean) through a biophysical approach is here developed. Six meadows located in Liguria (Italy) and Corsica (France) were investigated by applying the emergy analysis to assess the natural capital (NC) stocked by leaves and rhizomes components. Results highlighted the importance of carrying out an analysis of the variations in the NC value in both components: rhizomes defined the growth stage and the capacity to store NC over time; leaves provided information on the variability due to disturbances in the water column. Emergy analysis allows defining the NC, in terms of resources needed to maintain the meadows and to provide services to coastal communities. This research is inserted into the effort of incorporating the NC evaluation into marine planning and decision making to achieve nature conservation goals, while ensuring the sustainable exploitation of marine resources.

This research is part of the LTER (Long-Term Ecological Research) project, a network of terrestrial, freshwater, transitional water and marine sites, on which ecological research is conducted on a multi-decade scale. LTER studies ecosystems, their dynamics and evolution, the relationships between biodiversity and ecological functionality, water quality, productivity, the role of resource availability, the effects of pollution and climate change. The research focuses on the study of the variability of zooplankton groups in the Portofino marine protected area, in Punta Faro. The samplings were carried out in the years 2018–2019, and the results were compared with the values of the years 2003–2005, interesting from a meteorological climatic and biological point of view. The plankton community of the Punta Faro system was analyzed by means of a modeling approach to obtain information on the functionality and health status of the system and to verify whether this has undergone any alterations in the last decade. The analyses carried out show a clear difference between the three-year period 2003–2005 and the two-year period 2018–2019, highlighting how environmental changes, such as the increase in temperature, have led to higher costs of system functioning in the last two years. The mesozooplankton community has changed both in terms of abundance of organisms and in terms of organization and functionality.