Coral populations from reef habitats that experience extreme daily abiotic fluctuations have been suggested as candidates to survive and proliferate under future climate change. Few studies, however, have exposed corals from dynamic environments to the synergistic effects of ocean warming and acidification to investigate whether tolerance of present-day environmental variability is maintained under future climate stress. This study assessed the impact of RCP2.6 (+0.8°C and +25 ppm) and RCP4.5 (+1.3°C and +66 ppm) ocean warming and acidification on the survivorship, primary calcification (i.e., extension), secondary calcification (i.e., densification), and protein densities of Isopora palifera originating from two distinct reef habitats (abiotically variable reef flat vs. stable reef slope) over 9 weeks. Temperature and pCO₂ were offset from a reef slope baseline temperature of 26.0°C ± 0.6°C and pCO₂ concentration of 559 ± 56 ppm, incorporating natural diurnal variability. A trade-off was observed in I. palifera originating from the reef flat, which significantly increased tissue protein densities but reduced densification relative to corals from the reef slope. Survivorship nor extension rates differed between corals originating from the variable or stable reef habitats. Mortality increased under RCP4.5 as extension rates increased, indicating that energetic investment in skeletal expansion becomes unsustainable under future climate stress. Increasing temperature and CO₂ reduced calcification rates irrespective of the corals originating reef habitat suggesting with future climate change, exposure to greater environmental variability may not benefit coral calcification. These results demonstrate that tolerance to present-day abiotic variability does not necessarily infer resilience to moderate future ocean warming and acidification conditions.

中文翻译：

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对高度可变环境的耐受性并不意味着分支珊瑚对未来海洋变暖和酸化的恢复能力

来自经历极端日常非生物波动的珊瑚礁栖息地的珊瑚种群已被建议作为在未来气候变化下生存和增殖的候选者。然而，很少有研究将珊瑚从动态环境中暴露于海洋变暖和酸化的协同效应，以研究在未来的气候压力下是否能保持对当前环境变化的耐受性。本研究评估了 RCP2.6（+0.8°C 和 +25 ppm）和 RCP4.5（+1.3°C 和 +66 ppm）海洋变暖和酸化对生存、原发性钙化（即扩展）、继发性的影响Isopora palifera的钙化（即致密化）和蛋白质密度来自两个不同的珊瑚礁栖息地（非生物可变的礁滩与稳定的礁坡）超过 9 周。温度和 pCO ₂偏离礁坡基线温度 26.0°C ± 0.6°C 和 pCO ₂浓度 559 ± 56 ppm，包括自然日变化。在I. palifera中观察到了权衡起源于礁滩，与来自礁坡的珊瑚相比，它显着增加了组织蛋白密度，但降低了致密化。来自可变或稳定的珊瑚礁栖息地的珊瑚之间的存活率和扩展率不同。随着延伸率的增加，RCP4.5 下的死亡率增加，这表明在未来的气候压力下，对骨骼扩张的积极投资变得不可持续。升高温度和 CO ₂无论珊瑚起源于珊瑚礁栖息地如何，都降低了钙化率，这表明随着未来的气候变化，暴露于更大的环境变化可能不会有利于珊瑚钙化。这些结果表明，对当今非生物变异性的耐受性并不一定会推断出对未来海洋变暖和酸化条件的适应力。