Five years of observation on ocean acidification in the North Adriatic Sea. The experience of PALOMA station in the Gulf of Trieste

The Gulf of Trieste is a shallow bay (deep less than 25 m) lying in the northernmost part of the Adriatic Sea (Mediterranean Basin), where cold north-easterly winds often blows during winter producing cold dense water masses that are expected to be enriched in CO2. Meteorological conditions exhibit a pronounced seasonal cycle, causing wide variations of the physical properties in the water column through the year. In January 2008 a monitoring activity started by the elastic beacon PALOMA, located in the centre of the gulf. Meteorological and marine (physical and biogeochemical) parameters were collected, aimed at studying the inorganic carbon biogeochemistry and ocean acidification process in this highly variable coastal area. Since August 2012, the time series of physical and biogeochemical parameters (T, S, nutrients, Dissolved oxygen, pHT, AT, DOC) has been improoved with continuous measurements of seawater pCO2, temperature and salinity at 3 m below the surface. In 2010 PALOMA station has been included in the North Adriatic LTER site and is often visited during basin scale surveys. Here we present the main results of these five years activity highlighting the most relevant scientific results and underpinning the potential vulnerability of this area to the acidification process.