A Fundamental Paradigm for Coral Reef Carbonate Sediment Dissolution
13th International Coral Reef Symposium, Honolulu, Hawaii, June 19-24, 2016
The success of coral reefs depends on a positive balance of calcium carbonate production exceeding dissolution, erosion, and material export. As a result of ocean acidification, coral reefs could transition from net accretion to net erosion owing to decreasing rates of calcification and increasing rates of CaCO3 dissolution and bioerosion. Here, we present a fundamental paradigm that aims to explain the main driver of carbonate sediment dissolution on coral reefs based on theory and empirical datasets of pore water carbonate chemistry from diverse reef locations in the Atlantic and Pacific. We suggest that carbonate sediment dissolution is most strongly controlled by the extent of organic matter decomposition in the sediments, but that the magnitude of dissolution is influenced by how much decomposition is required to reach pore water undersaturation with respect to the most soluble bulk carbonate mineral phase present in the sediments, a condition defined as the Carbonate Critical Threshold (CCT). Decomposition of organic matter beyond the CCT under aerobic conditions results in stoichiometric proportional dissolution of carbonate sediments. As ocean acidification proceeds over the next several decades, the extent of organic matter decomposition required to reach the CCT will decrease, carbonate dissolution will increase, and subsequently the accumulation of carbonate sediments will decrease.
Andersson, Andreas J.; Cyronak, Tyler; and Eyre, Bradley D., "A Fundamental Paradigm for Coral Reef Carbonate Sediment Dissolution" (2016). Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures. 566.