Ocean acidification (OA) and other climate change-induced environmental alterations are resulting in unprecedented rates of environmental degradation. This environmental change is generally thought to be too fast for adaptation using evolutionary process dependent on natural selection, and thus, resilience may be related to the presence of existing tolerant genotypes and species. Estuaries undergo natural partial pressure carbon dioxide (pCO₂) fluctuations, with levels regularly exceeding predicted end of the century values. In this study, we use the estuarine orange-spotted grouper (Epinephelus coioides) to explore the intrinsic resilience to elevated pCO₂. Our sensitivity endpoints included: survival, heart rate, growth, and yolk consumption. Furthermore, we attempted to determine whether their acid–base regulatory machinery was plastic in response to elevated pCO₂ by analysing the gene expression of key transporters and ionocyte density. Survival was not significantly altered by exposure to elevated pCO₂. Interestingly, the heart rate was significantly elevated at both 1500 and 3100 μatm exposure. However, other metrics of energetic consumption, such as yolk consumption and growth, were not significantly altered. Furthermore, we found no changes in gene expression in vha, nhe3, and nbc, as well as ionocyte density at elevated pCO₂. Overall, these results support the hypothesis that estuarine species are resilient to the impacts of OA.

中文翻译：

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斑橙色斑的石斑鱼（Epinephelus coioides）的早期生命期表现出对高碳酸血症的抵抗力

海洋酸化（OA）和其他由气候变化引起的环境变化正在导致前所未有的环境退化速度。通常认为，这种环境变化对于使用依赖于自然选择的进化过程进行适应而言太快了，因此，复原力可能与现有的耐受基因型和物种的存在有关。河口会经历自然的分压二氧化碳（p CO ₂）波动，其水平经常超过本世纪末的预测值。在这项研究中，我们使用河口橙斑石斑鱼（Epinephelus coioides）探索对升高的p CO ₂的内在适应力。我们的敏感性终点包括：生存率，心率，生长和蛋黄消耗。此外，我们试图通过分析关键转运蛋白的基因表达和离子细胞密度来确定其酸碱调节机制是否对p CO ₂升高具有塑性。暴露于升高的p CO ₂不会明显改变存活率。有趣的是，在1500和3100μatm暴露量下，心率均显着升高。但是，其他高能消耗指标（如蛋黄消耗和生长）没有显着改变。此外，我们发现vha，nhe3和nbc中的基因表达没有变化以及p CO ₂升高时的离子细胞密度。总体而言，这些结果支持以下假设：河口物种对OA的影响具有弹性。