A multiscale observing approach for understanding acidification process in a marginal sea (northern Adriatic)

The Northern Adriatic is a shallow, semi-enclosed industrialized sub-basin of the Mediterranean affected by significant ecosystemchanges, which are studied through several research activities including the long-term monitoring of ILTER international network.Changes of pHT (-0.06) and TA (+74 ?mol/kg) in dense winter waters over the last 25 years already showed that this area is prone toacidification process under a complex inorganic carbon chemistry variability. To understand these changes, monthly sampling of themain biogeochemical and biological parameters has been carrying out since 2008 by a fixed station (PALOMA, Gulf of Trieste). In 2013the site has been implemented with continuous pCO2 measurements at 3 m depth and has been regularly visiting during basin widesurveys for the last two years. The combination of automated in situ measurements, monthly samplings and basin scaleoceanographic cruises is used to better understand the processes controlling air-sea CO2 fluxes and inorganic carbon chemistry underthree different scenarios: an extreme event of dense water formation, the phytoplankton blooms associated with riverine inputs andthe late-summer marked oxygen under saturation in the deeper waters.