The influence of seawater pCO2 and temperature on the amino acid composition and aragonite CO3 disorder of coral skeletons

• Published in: Coral Reefs
• Main Authors: Allison, Nicola, Ross, Phoebe, Castillo Alvarez, Cristina, Penkman, Kirsty, Kröger, Roland, Kellock, Celeste, Cole, Catherine, Clog, Matthieu, Evans, David, Hintz, Chris, Hintz, Kenneth, Finch, Adrian Anthony
• Other Authors: NERC, University of St Andrews.School of Earth & Environmental Sciences, University of St Andrews.Marine Alliance for Science & Technology Scotland, University of St Andrews.Scottish Oceans Institute, University of St Andrews.St Andrews Isotope Geochemistry, University of St Andrews.Centre for Energy Ethics
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2024
• Subjects: Biomineral; Ocean acidification; Raman; Organic matrix; GE Environmental Sciences; DAS; GE
• Online Access: https://hdl.handle.net/10023/30464; https://doi.org/10.1007/s00338-024-02539-z

Funding: This work was supported by the Leverhulme Trust (Research project Grant 2015-268 to NA, RK, and KP) and the UK Natural Environment Research Council (NE/G015791/1 to NA and AAF; NE/S001417/1 to NA, KP, RK, MC and AAF). The Raman microscope at the University of St. Andrews is supported by the EPSRC Light Element Analysis Facility Grant EP/T019298/1 and the EPSRC Strategic Equipment Resource Grant EP/R023751/1. Coral skeletons are composites of aragonite and biomolecules. We report the concentrations of 11 amino acids in massive Porites spp. coral skeletons cultured at two temperatures (25°C and 28°C) and three seawater pCO2 (180, 400 and 750 µatm). Coral skeletal aspartic acid/asparagine (Asx), glutamic acid/glutamine (Glx), glycine, serine and total amino acid concentrations are significantly higher at 28°C than at 25°C. Skeletal Asx, Glx, Gly, Ser, Ala, L-Thr and total amino acid are significantly lower at 180 µatm seawater pCO2 compared to 400 µatm and Ser is reduced at 180 µatm compared to 750 µatm. Concentrations of all skeletal amino acids are significantly inversely related to coral calcification rate but not to calcification media pH. Raman spectroscopy of these and additional specimens indicates that CO3 disorder in the skeletal aragonite lattice is not affected by seawater pCO2 but decreases at the higher temperature. This is contrary to observations in synthetic aragonite where disorder is positively related to the aragonite precipitation rate mediated by either increasing temperature (this study) or increasing Ω (this study and a previous report) and to the concentration of amino acid in the precipitation media (a previous report). We observe no significant relationship between structural disorder and coral calcification rate or skeletal [amino acid]. Both temperature and seawater pCO2 can significantly affect skeletal amino acid composition and further work is required to clarify how environmental change mediates disorder. Peer reviewed