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Ocean acidification effects on calcification in pCO2 acclimated Caribbean scleractinian coral
Hankins, C., L. Enzor, D. Vivian, M. Barron, AND W. Fisher. Ocean acidification effects on calcification in pCO2 acclimated Caribbean scleractinian coral. 2016 Ocean Sciences Meeting, New Orleans, LA, February 21 - 26, 2016.
Preliminary results suggest that coral acclimated at a higher pCO2 level than present day corals show no significant difference in calcification. Long acclimation periods of coral to near term future pCO2 levels may more accurately predict calcification responses in corals of the future.
Ocean acidification (OA) is projected to increase the acidity of coral reef habitats 2-3 times that of present day pCO2 levels. Many studies have shown the adverse effects on scleractinian calcification when exposed to elevated pCO2 levels, however, in these studies, corals have little to no acclimation to lower pH water conditions before experimentation. In this study, all corals were acclimated in culture for one year prior to being used in experimental trials. Data from culture systems shows coral experience a range of pCO2 from 300-600 µatm over the course of a day. This range is attributed to respiration and photosynthesis which also naturally occurs in a reef habitat. Montastrea cavernosa, Orbicella faveolata, and Pseudodiploria clivosa were exposed to their ambient culture conditions (control) or to elevated pCO2 levels of 1000 µatm (IPCC A1F1 scenario). By combining photographic analysis of live tissue area or exposed skeleton with the buoyant weight technique, an area density of each coral fragment was obtained to infer rates of calcification or erosion of skeleton. After two months of experimental exposure, preliminary results suggest that there is no significant difference in calcification or erosion in any of the species tested. Long acclimation periods (>8 weeks) of coral to near term future pCO2 levels may more accurately predict calcification responses in corals of the future.