Rising carbon dioxide (CO) in aquatic ecosystems due to climate change is a challenge for aquatic ectotherms. We examined whether interindividual variation in behavioural responses to CO could predict how a teleost fish would respond to elevated CO for multiple phenotypic and molecular traits. To this end, we first quantified behavioural responses of individuals exposed to acute elevated CO, and used these to assign individuals as either high or low responders relative to the population mean. Subsequently, we exposed both high and low responders to elevated CO for 6 weeks and quantified the effect on body condition, behaviour, and mRNA transcript responses of gill and liver genes associated with relevant physiological processes. Generally, we found few relationships between the phenotypic groups and body condition and behaviour following the CO exposure period; however, stark differences between the phenotypic groups with respect to gene transcripts from each tissue related to various processes were found, mostly independent of CO exposure. The most pronounced changes were in the gill transcripts related to acid-base regulation, suggesting that the observed behavioural variation used to assign fish to phenotypic groups may have an underlying molecular origin. Should the link between behaviour and gene transcripts be shown to have a fitness advantage and be maintained across generations, interindividual variation in behavioural responses to acute CO exposure may be a viable and non-invasive tool to predict future population responses to elevated aquatic CO.

中文翻译：

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响应CO2升高的个体间行为差异可预测青鳉（Oryzias latipes）酸碱调节相关基因的mRNA转录本丰度

由于气候变化，水生生态系统中二氧化碳（CO）的增加对水生变温动物来说是一个挑战。我们研究了个体间对二氧化碳行为反应的差异是否可以预测硬骨鱼对二氧化碳升高的多种表型和分子特征的反应。为此，我们首先量化了暴露于急性升高的二氧化碳的个体的行为反应，并利用这些将个体分配为相对于总体平均值的高反应者或低反应者。随后，我们将高反应者和低反应者暴露于升高的 CO 环境 6 周，并量化其对身体状况、行为以及与相关生理过程相关的鳃和肝脏基因的 mRNA 转录反应的影响。一般来说，我们发现表型群体与 CO 暴露期后的身体状况和行为之间几乎没有关系；然而，发现表型组之间与各种过程相关的每个组织的基因转录本存在明显差异，这些差异大多与二氧化碳暴露无关。最显着的变化是与酸碱调节相关的鳃转录本，这表明观察到的用于将鱼类分配到表型组的行为变异可能具有潜在的分子起源。如果行为和基因转录本之间的联系被证明具有适应性优势并且能够在几代人之间维持，那么对急性二氧化碳暴露的行为反应的个体间差异可能是预测未来人群对水生二氧化碳升高的反应的可行且非侵入性的工具。