The role of forcing agents on biogeochemical variability along the southwestern Adriatic coast: The Gulf of Manfredonia case study

- The Western Adriatic Current is a nutrient source north of the Gargano peninsula.
- Hydrography of the Gulf is controlled by river discharge, winds and currents.
- Small river discharge is an important nutrient and CDOM source in the Gulf of Manfredonia in winter.
- High riverine discharge events confine the WAC influence to the gulf's offshore waters.
- Biological production and degradation are a source of CDOM in spring -summer.

This study investigates how multiple forcing factors such as rivers, surface marine circulation and winds affect hydrology and biogeochemical processes in the Gulf of Manfredonia and the seas around the Gargano peninsula, in the south-western Adriatic Sea. The study adopted an integrated approach, using in situ and remote sensing data, as well as the output of current models. The data reveal variability in the area's hydrography induced by local freshwater sources, the Western Adriatic Current (WAC) flowing from the north along the Italian coast, and the current patterns under different wind regimes. Specifically, exchange with offshore waters in the gulf induces variability in salinity and biogeochemical content, even within the same season, i.e. winter, in our case. This strong dependence on physical and biogeochemical factors makes the Manfredonia-Gargano ecosystem vulnerable to climate change, which could compromise its important role as a nursery area for the Adriatic Sea.

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