Living coral tissue slows skeletal dissolution related to ocean acidification

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Climate change is causing major changes to marine ecosystems globally, with ocean acidification of particular concern for coral reefs. Using a 200 d in situ carbon dioxide enrichment study on Heron Island, Australia, we simulated future ocean acidification conditions, and found reduced pH led to a drastic decline in net calcification of living corals to no net growth, and accelerated disintegration of dead corals. Net calcification declined more severely than in previous studies due to exposure to the natural community of bioeroding organisms in this in situ study and to a longer experimental duration. Our data suggest that reef flat corals reach net dissolution at an aragonite saturation state (ΩAR) of 2.3 (95% confidence interval: 1.8–2.8) with 100% living coral cover and at ΩAR > 3.5 with 30% living coral cover. This model suggests that areas of the reef with relatively low coral mortality, where living coral cover is high, are likely to be resistant to carbon dioxide-induced reef dissolution.

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Fig. 1: The CP-FOCE system deployed on the Heron Island reef flat.
Fig. 2: pH levels in the FOCE flumes and controls throughout the experiment and the changes in coral annual buoyant weights.
Fig. 3: Observed and estimated responses of changes in annual buoyant weight as a function of ΩAR and coral status (live versus dead).
Fig. 4: Illustration revealing the drivers of the dynamic balance between growth and dissolution on a coral reef.

Data availability

All data generated or analysed during this study are included in this published article and its Supplementary information files.

Code availability

Script files and associated data for analysis can be found at


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We acknowledge the Australian Research Council (ARC) Linkage Infrastructure, Equipment and Facilities (grant no. LE0989608 to O.H.-G., S.D. and D.I.K.); an ARC Linkage grant (no. LP0775303); an ARC Centre of Excellence grant (no. CE0561435); a Queensland Government Smart State Premier’s Fellowship to O.H.-G.; a Schmidt Marine Technology Partners grant (nos. G-1605-55984 and G-1802-57451 to D.I.K.); National Science Foundation grants (nos. OCE-0729236 to R.B.D. and ATM-0941760 to B.G.M.); and the Pacific Blue Foundation for supporting this research. We thank staff at the Heron Island Research Station, especially M. Roy, S. Venn, K. Hay and L. Perkins for their support throughout this project. We also thank staff at the University of Queensland Engineering Instrumentation Workshop, especially R. White, G. Manning, P. Blakely and M. James. Permits from the Department of Environment and Resource Management (no. CSCE00874010) and the GBR Marine Park Authority (no. G09/29996.1) were provided to conduct this research.

Author information

D.I.K., S.D. and O.H.-G. conceived of and designed the experiment. D.I.K, T.M., A.C. and M.M. designed and built the CP-FOCE experimental system. D.I.K., L.T., K.S., K.C., T.M., A.C., M.M., R.B.D., B.G.M., S.D. and O.H.-G. collected the data and conducted the field experiments. D.I.K., L.T. and D.K.O. analysed the data. D.I.K. and L.T. wrote the manuscript with input from all co-authors.

Correspondence to David I. Kline.

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Supplementary information

Supplementary Information

Supplementary Fig. 1 and text summaries for Datasets 1–3.

Reporting Summary

Supplementary Dataset 1

Continuous pH, T, PAR, tides.

Supplementary Dataset 2

Discrete chem.

Supplementary Dataset 3

Buoyant weights.

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Kline, D.I., Teneva, L., Okamoto, D.K. et al. Living coral tissue slows skeletal dissolution related to ocean acidification. Nat Ecol Evol 3, 1438–1444 (2019) doi:10.1038/s41559-019-0988-x

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