Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification.
Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification.
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作者：
Gori A;Ferrier-Pagès C;Hennige SJ;Murray F;Rottier C;Wicks LC;Roberts JM
人为碳排放导致的气温上升和海洋酸化威胁着热带和温带珊瑚。然而，这些压力源对珊瑚生理学的协同效应仍然知之甚少，特别是对于冷水珊瑚。本研究评估了分布广泛的冷水珊瑚 Desmophyllum dianthus 在两种温度（环境 12 °C 和升高 15 °C）和两种 pCO2 条件（环境 390 ppm 和升高 750 ppm）下维持约 8 个月时的关键生理参数（钙化、呼吸和铵排泄）的变化。在环境温度下，在任一 pCO2 水平下均未观察到瞬时钙化、呼吸或铵排泄速率的变化。相反，升高温度 (15 °C) 显着降低钙化速率，升高温度和 pCO2 相结合显着降低呼吸速率。呼吸氧与排泄氮 (O:N) 比率的变化提供了代谢主要能量来源的信息，表明从在控制条件下混合使用蛋白质和碳水化合物/脂质作为代谢底物，转向在两种应激源下以效率较低的蛋白质为主的分解代谢。总体而言，这项研究表明，石竹的生理机能对热压力比 pCO2 压力更敏感，并且预计未来几十年气温上升和海洋酸化的结合可能会严重影响这种冷水珊瑚物种。
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.