Stable isotopic composition of coralline sponge skeletons. Historic record (interdecadal to several hundreds of years) of carbon isotopes in surface water dissolved inorganic carbon. Implications for global carbon cycle and atmosphere - surface water - subsurface water interactions. Implications for historic marine climate changes. Influence of industrial CO2 release. Oceanic CO2 uptake. Caribbean (Jamaica, Pedro Bank) and Coral Sea (New Caledonia, Great Barrier Reef).