Acidification of seawater owing to oceanic uptake of atmospheric CO 2 originating from human activities such as burning of fossil fuels and land-use changes has raised serious concerns for its adverse effects on corals, coral reefs and carbonate communities in general. Here we demonstrate a transition from net accumulation towards net loss of calcium carbonate (CaCO3) material owing to decreased calcification and increased carbonate dissolution from replicated subtropical coral reef communities (nCombining double low line3) incubated in continuous-flow mesocosms subject to present and future seawater conditions. The calcifying community was dominated by the coral Montipora capitata. Daily average community calcification or Net Ecosystem Calcification (NEC Combining double low line CaCO3 production ?????" dissolution) was positive at 4.5 mmol CaCO3 m−2 h−1 under ambient seawater pCO 2 conditions as opposed to negative at −0.1 mmol CaCO 3 m−2 h−1 under seawater conditions of double the ambient pCO2. These experimental results provide support for the conclusion that some net calcifying communities could become subject to net dissolution in response to anthropogenic ocean acidification within this century.
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Net loss of CaCO3 from coral reef communities due to human induced seawater acidification