Published online by Cambridge University Press: 21 July 2017
As shallow-water reefs decline worldwide, opportunities abound for researchers to expand understanding of carbonate depositional systems. Recognizing the myriad of paradoxes associated with reefs and carbonate research hopefully can stimulate new questions that will assist researchers in understanding paleoenvironmental changes and mass extinction events. Two often counter-intuitive concepts are discussed, first that coral reefs thrive in clear, nutrient-poor waters, except when they don't; and second, that aragonite is energetically efficient for reef-builders to precipitate in tropical waters, except when it isn't. Coordinated studies of carbonate geochemistry with photozoan physiology and calcification will contribute to understanding carbonate sedimentation under environmental change, both in the future and in the geologic record.