Ecosystem services derived from SGD: a perspective from traditional and academic knowledge in Mediterranean societies

Submarine Groundwater Discharge (SGD) is recognized as a fundamental hydrological process that supports many coastal biogeochemical cycles and social-ecological systems. However, very little has been investigated about how SGD affects society and human well-being. Coastal services provided by ecosystems dependent on SGD can be analyzed and clustered into the four main categories of Ecosystem Services (i.e., Provisioning, Supporting, Regulating and Cultural), which are divided into subcategories defined as outcomes. This enables identifying and discussing both benefits and threats to coastal societies resulting from SGD outcomes. Due to the lack of academic literature on this matter, here we explore the academic and local knowledge of the social perception toward SGD and its ecosystem services (ES). This research is conducted through two case studies, the island of Mallorca and the Region of Salento, to unravel the similarities and particularities of each Mediterranean society regarding the SGD-ES identified and their historical evolution. Such evolution transitions from the management of the fresh groundwaters for human consumption to the exploitation by the tourism industry of cultural ecosystem services related to the same discharge. Our review also shows how compiling different search possibilities (e.g., local languages, including paper-based documents; grey literature; local knowledge; academic literature) has resulted in a significant increase in the reported ES and its understanding. In this direction, combing traditional and academic knowledge are key to accessing society's perception of most cultural ES. Therefore, SGD-ES studies are extremely locally-dependent, and thus regional or global require an in-depth understanding of all areas comprehended in the study. Overall, the research presented in this study contributes to a better understanding of the complexity of the SGD and its social implications. Therefore, this research presents to the academic community new insights from traditional knowledge and an opportunity to integrate multidisciplinarity into a study subject that has usually only been looked from the prism of natural sciences.