The combined effects of ocean acidification and copper on the physiological responses of the tropical coral Stylophora pistillata

• Published in: Marine Environmental Research
• Main Authors: Cryer, S. E., Schlosser, Christian, Allison, N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2022
• Subjects: Ocean acidification
• Online Access: https://oceanrep.geomar.de/id/eprint/55759/; https://oceanrep.geomar.de/id/eprint/55759/1/Cryer%20et%20al.pdf; https://doi.org/10.1016/j.marenvres.2022.105610

Highlights • Exposure to increased Cu concentrations suppressed coral calcification. • Calcification was suppressed further when exposed to Cu under high pCO2. • Respiration decreased after two weeks when stressors were applied in combination. A decrease in ocean pH of 0.3 units will likely double the proportion of dissolved copper (Cu) present as the free metal ion, Cu2+, the most bioavailable form of Cu, and one of the most common marine pollutants. We assess the impact of ocean acidification and Cu, separately and in combination, on calcification, photosynthesis and respiration of sub-colonies of a single tropical Stylophora pistillata colony. After 15 days of treatment, total calcification rates were significantly decreased in corals exposed to high seawater pCO2 (∼1000-μatm, 2100 scenario) and at both ambient (1.6–1.9 nmols) and high (2.5–3.6 nmols) dissolved Cu concentrations compared to controls. The effect was increased when both stressors were combined. Coral respiration rates were significantly reduced by the combined stressors after 2 weeks of exposure, indicating the importance of experiment duration. It is therefore likely rising atmospheric CO2 will exacerbate the negative effects of Cu pollution to S. pistillata.