Data for the research article "High-resolution reconstruction of pH upregulation and its seasonal drivers in the temperate coral Cladocora caespitosa"

This repository contains the coral calcification and geochemical data files used to generate the results for the following article: MJ. Vergotti, DK. Kersting, TC. Brachert, S. Comeau, DA. Frick, EC. Hathorne, MJ. Henehan, J. Holtz, N. Teixidó, V. van Schijndel, JP. D'olivo (in prep.) High-resolution reconstruction of pH upregulation and its seasonal drivers in the temperate coral Cladocora caespitosa. Abstract: Ocean acidification (OA) and associated changes in seawater carbonate chemistry, combined with thermal stress, hampers coral calcification. By upregulating pH and dissolved inorganic carbon, corals can optimize their calcification, giving them some resilience to OA. Little is known about the seasonal- and interannual scale impacts of thermal stress and OA on pH upregulation and calcification in the temperate coral Cladocora caespitosa, despite it being the only zooxanthellate reef builder in the Mediterranean Sea. δ¹¹B and B/Ca were determined seasonally in C. caespitosa skeletons from two NW Mediterranean sites to reconstruct the effect of seawater temperature and pH on the carbonate chemistry of the coral calcifying fluid (CF), at a bimonthly resolution from June 2013 to August 2017 (Columbretes Islands, Spain), and June 2016 to February 2022 (Villefranche-sur-Mer, France). Cladocora caespitosa displayed a similar pH upregulation strategy to most tropical corals, albeit with an apparently lower sensitivity to seasonal environmental change. Temperature was the main driver of seasonal variability in the CF composition and coral calcification, with seawater pH having a comparatively lower seasonal variability, and acting on longer timescales. While longer coral records and investigations into inter-population variability would still be beneficial in order to fully understand the response of C. caespitosa to environmental change, our records constitute an important first step in understanding the biomineralization strategy of this ecologically important coral species. Funding and acknowledgments: We thank the Secretaría General de Pesca (MAPA) and the Columbretes Islands Marine Reserve staff for sampling authorization and logistic support in the gathering of biological and environmental data. We thank Dr. J.E. Hoffmann for giving us access to the micro-mill. We thank Dr. B. Chen, Dr. S. Ring and A. Balduin for their support in the lab, and J. Bernebee-Sey for his assistance in processing the data. We thank G.O. Cardoso for insightful conversations and early manuscript readings and comments. This study was partially funded by the European Union’s Horizon 2020 program of research and innovation (under the MaCoBioS grant agreement no. 869710), and by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, project no. 401447620).