The marine carbonate system dynamics in fragile environments: insights from the North Atlantic and Mediterranean basins

Abstract

The ocean is a major carbon reservoir containing approximately 37,700 Gt C (1 Gt = 1015 g), which represent about 43 times the amount estimated in the atmosphere (Friedlingstein et al., 2025). The largest fraction of carbon in the ocean is present as dissolved inorganic carbon within the Marine Carbonate System (MCS). This system plays a crucial role regulating the exchange of carbon dioxide (CO2) among the biosphere, lithosphere, atmosphere, and hydrosphere. The MCS has been widely described (i.e. Edmond and Gieskes, 1970; Millero, 1995, 1979, 2007; Dickson et al., 2007) and is also referred as to marine CO2 system or CO2- carbonate system. It involves the dissolution of CO2 in seawater and its subsequent hydration to yield carbonic acid (H2CO3), following a series of chemical equilibria in seawater [..]