A coralline alga gains tolerance to ocean acidification over multiple generations of exposure

• Published in: Nature Climate Change
• Main Authors: Cornwall, C. E., Comeau, S., De Carlo, Thomas Mario, Larcombe, E., Moore, B., Giltrow, K., Puerzer, F., D’Alexis, Q., McCulloch, Malcolm T.
• Other Authors: Biological and Environmental Sciences and Engineering (BESE) Division, Red Sea Research Center (RSRC), Oceans Graduate School and Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia, ARC Centre of Excellence for Coral Reef Studies, The University of Western Australia, Crawley, Western Australia, Australia, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand, Sorbonne Université, CNRS-INSU, Laboratoire d’Océanographie de Villefranche, Villefranche-sur-mer, France
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Science and Business Media LLC 2020
• Subjects: McCoy; New Zealand; Ocean acidification
• Online Access: http://hdl.handle.net/10754/661361; https://doi.org/10.1038/s41558-019-0681-8

Crustose coralline algae play a crucial role in the building of reefs in the photic zones of nearshore ecosystems globally, and are highly susceptible to ocean acidification1–3. Nevertheless, the extent to which ecologically important crustose coralline algae can gain tolerance to ocean acidification over multiple generations of exposure is unknown. We show that, while calcification of juvenile crustose coralline algae is initially highly sensitive to ocean acidification, after six generations of exposure the effects of ocean acidification disappear. A reciprocal transplant experiment conducted on the seventh generation, where half of all replicates were interchanged across treatments, confirmed that they had acquired tolerance to low pH and not simply to laboratory conditions. Neither exposure to greater pH variability, nor chemical conditions within the micro-scale calcifying fluid internally, appeared to play a role in fostering this capacity. Our results demonstrate that reef-accreting taxa can gain tolerance to ocean acidification over multiple generations of exposure, suggesting that some of these cosmopolitan species could maintain their critical ecological role in reef formation. We thank A.-M. Nisumaa-Comeau, G. Ellwood and J. P. D’Olivo for laboratory assistance; V. Schoepf and S. McCoy for comments on a previous version; and R. Townsend from the Western Australian Museum for training in species’ identification. M.T.M. was supported by an Australian Research Council (ARC) Laureate Fellowship (no. FL120100049) and C.E.C. and T.M.D. by the ARC Centre of Excellence for Coral Reef Studies (grant no. CE140100020). S.C. was supported by an ARC Discovery Early Career Researcher Award (no. DE160100668). C.E.C. was also supported by a Rutherford Discovery Fellowship from The Royal Society of New Zealand Te Apārangi (no. RDF-VUW1701).