Impact of ocean acidification on the carbonate sediment budget of a temperate mixed beach.

• Published in: Climatic Change
• Main Authors: Simone Simeone, Emanuela Molinaroli, Alessandro Conforti, Giovanni De Falco 1
• Other Authors: Simeone, Simone, Molinaroli, Emanuela, Conforti, Alessandro, 1, Giovanni De Falco
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Acidification; Beaches; Budget control; Carbon dioxide; Carbonation; Deposition rates; Ecosystems; Sea level; Underwater mineralogy; Settore GEO/04 - Geografia Fisica e Geomorfologia; Settore GEO/02 - Geologia Stratigrafica e Sedimentologica; Settore GEO/07 - Petrologia e Petrografia; Ocean acidification
• Online Access: http://hdl.handle.net/10278/3706919; https://doi.org/10.1007/s10584-018-2282-3; https://link.springer.com/article/10.1007/s10584-018-2282-3

The production of sediments by carbonate-producing ecosystems is an important input for beach sediment budgets in coastal areas where no terrigenous input occurs. Calcifying organisms are a major source of bioclastic carbonate sediment for coastal systems. Increased levels of CO 2 in the atmosphere are leading to an increase in the partial pressure of CO 2 on ocean seawater, causing ocean acidification (OA), with direct consequences for the pH of ocean waters. Most studies of OA focus on its impact on marine ecosystems. The impact of OA on carbonate-producing ecosystems could be to reduce the amount of sediments supplied to temperate coastal systems. The aim of this study was to quantify the effect of the predicted OA on the long-term sediment budget of a temperate Mediterranean mixed carbonate beach and dune system. Based on projections of OA we estimated a fall of about 31% in the present bioclastic carbonate sediment deposition rate, with the biggest decreases seen in the dunes ( − 46%). OA is also expected to affect the carbonate sediment reservoirs, increasing the disso- lution of CaCO 3 and causing net sediment loss from the system (~ 50,000 t century − 1 ). In the long-term, OA could also play a primary role in the response of these systems to sea-level rise. Indeed, the reduction in the quantity of carbonate sediments provided to the system may affect the speed with which the system is able to adapt to sea-level rise, by increasing wave run-up, and may promote erosion of dunes and subaerial beaches.