Aragonite is the primary mineral in cool water marine environments. Aragonite saturation state is a function of carbonate ion concentration and used to track ocean acidification. Aragonite is used by marine life “calcifiers,” organisms that construct their shells and skeletons from the mineral. Coral reefs are mainly found in regions where open ocean aragonite saturation is 3.0 or higher. Source: Marine Conservation Institute (MCI)Citation: Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC, et al. (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437: 681–686.The Marine Conservation Institute used this dataset as an input to a predictive habitat model documented in the publication Global Habitat Suitability for Framework-Forming Cold-Water Corals.