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Spatial and temporal variations of phytoplankton community structure were studied in the Gulf of Venice (Northern Adriatic Sea) from February 1999 to December 2001 (INTERREG II, Italia-Slovenia project). Phytoplankton samples were collected, with a monthly frequency, at 11 stations in the basin. Abundance, biomass, and species composition were considered. Synthetic descriptors were used in order to evaluate the main succession pattern and to cluster communities that typify different hydrological conditions. A decreasing gradient of abundance and biomass was generally observed from west to east, passing from the land-influenced waters to offshore. The seasonal pattern and inter-annual variability of the main phytoplankton taxa are described and discussed in relation with the occurrence of a massive mucilage event and of a Po River flood.

Coastal tourism is a growing industry sector in the Mediterranean Basin. This and the other human activities occurring along the coastline share space and resources, leading to conflicts for divergent uses. Moreover, the overexploitation of natural resources degrades and depletes coastal habitats, with negative feedback effects for all human activities. Hence, both tourism and the other human activities have to consider their dependence on coastal ecosystem services, and act at technical and policy level to reach a compromise that preserves natural resources in the long term. Here we provide a conceptual framework illustrating the complex relationships and trade-offs among threats from coastal tourism and from other human activities and coastal ecosystem services, with a focus on cultural ones. We discuss the negative feedbacks on tourism development and provide examples of geospatial analysis on cumulative threats generated by other human activities and affecting tourism itself. The proposed conceptual framework and the threat analysis aim at highlighting the negative feedback effects of human driven threats on the development of Mediterranean coastal tourism, through an ecosystem service perspective. Both tools provide valuable insight for supporting decision makers and planners in achieving integrated coastal management, with a focus on sustainable tourism.

Long-term data series (1971–2015) of physical and biogeochemical parameters were analyzed in order to assess trends and variability of oceanographic conditions in the northern Adriatic Sea (NAS), a mid-latitude shallow continental shelf strongly impacted by river discharges, human activities and climate changes. Interpolation maps and statistical models were applied to investigate seasonal and spatial variability, as well as decadal trends of temperature, salinity, chlorophyll-a and nutrients. This analysis shows that sea surface temperature increased by +0.36% year−1 over four decades. Annual mean flow of the Po River markedly changed due to the occurrence of periods of persistent drought, whereas the frequency of flow rates higher than 3000 m3 s−1 decreased between 2006 and 2015. Moreover, we observed a long-term decrease in surface phosphate concentrations in Po River water (−1.34% year−1) and in seawater (in summer −2.56% year−1) coupled, however, to a significant increase in nitrate concentration in seawater (+3.80% year−1) in almost all seasons. These changes indicate that the nutrient concentrations in the NAS have been largely modulated, in the last forty years, by the evolution of environmental management practices and of the runoff. This implies that further alteration of the marine environment must be expected as a consequence of the climate changes.