CO2‐induced seawater acidification has been shown to modify predator–prey interactions in many marine taxa. Scyphozoans play an important role in the trophic dynamics of marine ecosystems during their blooms in coastal waters; however, the impacts of seawater acidification on the predation behavior of these animals are poorly understood. Here, we aimed to examine the impact of a decrease in seawater pH on the feeding behavior and growth of ephyrae (juvenile medusae) of the scyphozoan Aurelia coerulea. Combining bulk and single‐cell RNA sequencing approaches, we assessed transcriptomic changes of ephyrae under a laboratory‐based pH 7.6 condition. We found that the feeding rates and growth of ephyrae were significantly inhibited by a decrease in seawater pH. Furthermore, transcriptome analysis showed that a decline in pH significantly reduced the expression of genes related to toxins and nematocyst structure in ephyrae. These findings were further confirmed by single‐cell transcriptomic analyses and revealed that low pH impaired the toxin activity and energy metabolism of stinging cells. The pH recovery experiment indicated that moving ephyrae from seawater with pH 7.6 into seawater with pH 8.1 greatly restored their feeding, growth, and toxin‐related and nematocyst structure–related gene expression. However, exposure to pH 7.6 for 23 d could not recover the decrease in the feeding and growth of ephyrae. Together, these findings indicate that CO2‐induced acidification compromised the stinging cells of A. coerulea ephyrae, with concomitant negative consequences on predation and growth that are likely to alter predator–prey interactions, with consequent effects on community structure and ecosystem.

中文翻译：

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二氧化碳引起的海水酸化损害水母的刺细胞


二氧化碳引起的海水酸化已被证明可以改变许多海洋类群中捕食者与猎物的相互作用。舟水母在沿海水域繁殖期间，在海洋生态系统的营养动态中发挥着重要作用；然而，人们对海水酸化对这些动物捕食行为的影响知之甚少。在这里，我们的目的是研究海水 pH 值下降对蓝蝾螈的摄食行为和蝶藻（幼年水母）生长的影响。结合批量和单细胞 RNA 测序方法，我们在实验室 pH 7.6 条件下评估了碟状体的转录组变化。我们发现，海水 pH 值的降低显着抑制了蝶藻的摄食率和生长。此外，转录组分析表明，pH 值下降显着降低了与蝶藻中毒素和线虫囊结构相关的基因的表达。这些发现得到单细胞转录组分析的进一步证实，并表明低 pH 值会损害刺细胞的毒素活性和能量代谢。 pH恢复实验表明，将碟状体从pH 7.6的海水转移到pH 8.1的海水中，极大地恢复了其摄食、生长以及毒素相关和刺丝囊结构相关的基因表达。然而，暴露于pH 7.6 23 d并不能恢复蝶藻摄食和生长的减少。总之，这些发现表明，二氧化碳诱导的酸化损害了蓝花蜉蝣的刺细胞，随之而来的是对捕食和生长的负面影响，可能会改变捕食者与猎物的相互作用，从而对群落结构和生态系统产生影响。