Ocean acidification is also developing in the ocean interior  due to the transport of anthropogenic CO2 to depth by ocean currents and mixing . There, it leads to the shoaling of saturation horizons of aragonite and calcite  , below which dissolution of these calcium carbonate minerals is thermodynamically favoured. The calcite or aragonite saturation horizons have migrated upwards in the North Pacific   and in the Irminger Sea  . In some locations of the western Atlantic Ocean, calcite saturation depth has risen by ~300 m since the pre-industrial era due to increasing concentrations of deep-ocean dissolved inorganic carbon . In the Arctic, where some coastal surface waters are already undersaturated with respect to aragonite due to the degradation of terrestrial organic matter , the deep aragonite saturation horizon shoaled on average 270 + 60 m during 1765-2005 .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report