Anthropogenic ocean acidification (OA) is a threat to coral reef fishes, but few studies have investigated responses of high-trophic-level predators, including sharks. We tested the effects of 72-hr exposure to OA-relevant elevated partial pressures of carbon dioxide ( p CO 2 ) on oxygen uptake rates, acid–base status, and haematology of newborn tropical blacktip reef sharks ( Carcharhinus melanopterus ). Acute exposure to end-of-century p CO 2 levels resulted in elevated haematocrit (i.e. stress or compensation of oxygen uptake rates) and blood lactate concentrations (i.e. prolonged recovery) in the newborns. Conversely, whole blood and mean corpuscular haemoglobin concentrations, blood pH, estimates of standard and maximum metabolic rates, and aerobic scope remained unaffected. Taken together, newborn blacktip reef sharks appear physiologically robust to end-of-century p CO 2 levels, but less so than other, previously investigated, tropical carpet sharks. Our results suggest peak fluctuating p CO 2 levels in coral reef lagoons could still physiologically affect newborn reef sharks, but studies assessing the effects of long-term exposure and in combination with other anthropogenic stressors are needed.

中文翻译：

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严重暴露于海洋酸化条件的珊瑚礁鲨的反应

人为海洋酸化 (OA) 对珊瑚礁鱼类构成威胁，但很少有研究调查包括鲨鱼在内的高营养级捕食者的反应。我们测试了 72 小时暴露于 OA 相关升高的二氧化碳分压 (p CO 2 ) 对新生热带黑鳍礁鲨 (Carcharhinus melanopterus) 的摄氧率、酸碱状态和血液学的影响。世纪末 p CO 2 水平的急性暴露导致新生儿血细胞比容升高（即压力或氧摄取率补偿）和血乳酸浓度（即恢复时间延长）。相反，全血和平均红细胞血红蛋白浓度、血液 pH 值、标准和最大代谢率的估计值以及有氧范围不受影响。综合起来，新生的黑鳍礁鲨在本世纪末的 p CO 2 水平下似乎在生理上很强壮，但不如之前研究过的其他热带地毯鲨。我们的结果表明，珊瑚礁泻湖中峰值波动的 p CO 2 水平仍可能对新生礁鲨产生生理影响，但需要研究评估长期暴露以及与其他人为压力因素相结合的影响。