title: Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification.
abstract: Rising temperatures and ocean acidification driven by anthropogenic carbon emissions threaten both tropical and temperate corals. However, the synergistic effect of these stressors on coral physiology is still poorly understood, in particular for cold-water corals. This study assessed changes in key physiological parameters (calcification, respiration and ammonium excretion) of the widespread cold-water coral Desmophyllum dianthus maintained for ∼8 months at two temperatures (ambient 12 °C and elevated 15 °C) and two pCO2 conditions (ambient 390 ppm and elevated 750 ppm). At ambient temperatures no change in instantaneous calcification, respiration or ammonium excretion rates was observed at either pCO2 levels. Conversely, elevated temperature (15 °C) significantly reduced calcification rates, and combined elevated temperature and pCO2 significantly reduced respiration rates. Changes in the ratio of respired oxygen to excreted nitrogen (O:N), which provides information on the main sources of energy being metabolized, indicated a shift from mixed use of protein and carbohydrate/lipid as metabolic substrates under control conditions, to less efficient protein-dominated catabolism under both stressors. Overall, this study shows that the physiology of D. dianthus is more sensitive to thermal than pCO2 stress, and that the predicted combination of rising temperatures and ocean acidification in the coming decades may severely impact this cold-water coral species.
authors: Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University, Edinburgh, Scotland, United Kingdom; Coral Ecophysiology, Centre Scientifique de Monaco, Monaco, Principality of Monaco.
authors: Andrea
authors: A
authors: Gori
authors: Coral Ecophysiology, Centre Scientifique de Monaco , Monaco , Principality of Monaco.
authors: Christine
authors: C
authors: Ferrier-Pagès
authors: Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University , Edinburgh, Scotland , United Kingdom.
authors: Sebastian J
authors: SJ
authors: Hennige
authors: Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University , Edinburgh, Scotland , United Kingdom.
authors: Fiona
authors: F
authors: Murray
authors: Coral Ecophysiology, Centre Scientifique de Monaco , Monaco , Principality of Monaco.
authors: Cécile
authors: C
authors: Rottier
authors: Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University , Edinburgh, Scotland , United Kingdom.
authors: Laura C
authors: LC
authors: Wicks
authors: Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University , Edinburgh, Scotland , United Kingdom.
authors: J Murray
authors: JM
authors: Roberts
keywords: Cold-water corals; Coral calcification; Coral excretion; Coral respiration; Ocean acidification; Thermal stress