Late spring characterization of different coastal areas of the Adriatic Sea

Abstract

      The objective of this study is to analyze the physical and chemical characteristics of three coastal zones of the Adriatic Sea during late spring, and to identify similarities and differences among the zones. The trophic status of the Southeastern Adriatic-Sea, dominated by the discharge from the Buna/Bojana river delta watersheds, is compared with two other Adriatic regions: the Northwestern Adriatic Sea and the Southwestern Adriatic Sea (Gulf of Manfredonia); the first is dominated by the Po River freshwater discharge and the second is one of the most productive areas of the Southwestern Adriatic.
     The areas are influenced by two main Adriatic surface currents: the Eastern Adriatic Current (EAC) that flows north-westward, and the Western Adriatic Current (WAC) that flows south-eastward. The measurements of temperature, salinity, fluorescence, oxygen, nutrients and chlorophyll a in the three areas were collected and compared.
     The areas showed similar physical and bio-chemical characteristics, despite the Northern Adriatic is impacted by the Po River runoff and the WAC carries out along the Western Adriatic water rich of nutrients from the northern Italian rivers. The area affected by the Po River discharge showed maximum chlorophyll and nitrogen concentrations within the river plume. Moreover, the Southwestern Adriatic Sea showed a load of nutrients and organic matter connected to substances coming from the northern Italian rivers (mainly the Po River). Similarly, in the Southeastern Adriatic-Sea, the Buna/Bojana River discharge contained relatively high values in the regional chlorophyll distribution. The three areas are directly or indirectly linked to river plume dynamics and the associated inorganic and organic inputs determine the trophic state of the areas. In particular, the Southeastern Adriatic Sea was a meso-eutrophic area; despite the most eastern side of the Adriatic was an oligotrophic basin.