The count-down for calcifiers to dissolve in major Atlantic and Mediterranean water masses due to ocean acidification

5th International Symposium on the Ocean in a High CO2 World, 13-16 September, Lima, PerúThe oceanic uptake of atmospheric CO2 is driving changes in seawater chemistry that result in the decrease of both pH and the concentration of the carbonate ion, which is essential for marine calcifiers to build their hard structures and shells. Reduction in the availability of carbonate ions lowers the saturation state (Ω) for the calcium carbonate mineral aragonite in the ocean. When concentration of aragonite changes from oversaturation (Ω>1) to undersaturation (Ω