Rodriguez-Galvez

Abstract 16 17 The North Atlantic is the most important sink for atmospheric CO2 although there still 18 remain uncertainties about the total amount stored by this region and the contribution of 19 the anthropogenic CO2 (CANT) that is exchanged between the Mediterranean Sea and the 20 Atlantic Ocean. During the P3A2 cruise performed in October 2008 throughout the 21 oceanic area covered by the Gulf of Cádiz and the Strait of Gibraltar, which channelizes 22 the water exchange between the Atlantic and the Mediterranean, extensive 23 measurements of the carbon system parameters (pH, total alkalinity and total inorganic 24 carbon) and others related (dissolved oxygen and nutrients) were carried out to analyse 25 their distribution in the area. In order to study the CANT spatial variability, three 26 observational methods for CANT concentration assessment (φCTº, ∆C * and TrOCA) 27 were applied. The three water masses identified in the area, North Atlantic Central 28 Water (NACW), North Atlantic Deep Water (NADW) and Mediterranean Outflow 29 Water (MOW), were shown to contain different CANT concentration. NADW exhibited 3