Ocean regulates the concentration of CO2 in the atmosphere thanks to its capability to uptake and store CO2. Assessing CO2 fluxes between the atmosphere and ocean is crucial to determine both the level of ocean acidification and the capability of the ocean to contrast global warming.
CO2 fluxes measured in the North-eastern Mediterranean Sea (Levantine basin) during several seasonal samplings in coastal and open waters in the area between Cyprus and Rhodes islands between 2019 and 2022, showed a clear seasonal pattern. Summer was always characterized by a net outflux (from the ocean to the atmosphere), while winter displayed a weak CO2 sink, which intensified in the proximity of the Rhodes gyre. Annually, the North-eastern Levantine basin showed a net sink of CO2 from the atmosphere to the ocean. A positive linear correlation between surface pCO2 and temperature was reported in all seasons in the study area, suggesting that temperature was the major factor controlling surface pCO2 spatial distribution and seasonal variation. Decrease of pCO2 from the surface layer associated to phytoplankton production was reported just for a brief period in later winter (February-March). Local river discharges (Taşucu river) impact was only circumscribed to the immediate coastal area nearby the river outlet. Other coastal areas followed the same pattern observed in offshore areas.