Impact of ocean acidification in the metabolism and swimming behavior of the dolphinfish (Coryphaena hippurus) early larvae

Since the industrial revolution, [CO2]atm has increased from 280 µatm to levels now exceeding 380 µatm and is expected to rise to 730-1,020 µatm by the end of this century. The consequent changes in the ocean's chemistry (e.g., lower pH and availability of the carbonate ions) are expected to pose particular problems for marine organisms, especially in the more vulnerable early life stages. The aim of this study was to investigate how the future predictions of ocean acidification may compromise the metabolism and swimming capabilities of the recently hatched larvae of the tropical dolphinfish (Coryphaena hippurus). Here, we show that the future environmental hypercapnia (delta pH 0.5; 0.16 % CO2, ~1,600 µatm) significantly (p < 0.05) reduced oxygen consumption rate up to 17 %. Moreover, the swimming duration and orientation frequency also decreased with increasing pCO2 (50 and 62.5 %, respectively). We argue that these hypercapnia-driven metabolic and locomotory challenges may potentially influence recruitment, dispersal success, and the population dynamics of this circumtropical oceanic top predator.

自工业革命以来，大气二氧化碳（atmospheric CO₂）浓度已从280微大气压（µatm）攀升至当前的380微大气压以上，预计到本世纪末将升至730至1020微大气压。随之而来的海洋化学特征改变（如pH值降低、碳酸盐离子可利用性下降），预计将对海洋生物造成尤为严峻的生存挑战，尤其针对处于早期生命阶段的脆弱个体。本研究旨在探究未来海洋酸化（ocean acidification）情景下，热带鲯鳅（Coryphaena hippurus）刚孵化幼体的代谢功能与游泳能力会受到何种影响。研究结果表明，未来环境高碳酸血症（hypercapnia，pH降幅达0.5；二氧化碳体积占比0.16%，约1600微大气压）可使幼体耗氧率（oxygen consumption rate）显著降低17%（p < 0.05，具有统计学显著性）。此外，随着二氧化碳分压升高，幼体的游泳持续时长与定向游动频率分别下降了50%与62.5%。我们认为，这种由高碳酸血症引发的代谢与运动机能损伤，可能会对这种环热带海洋顶级捕食者的种群补充、扩散成功率及种群动态产生潜在影响。