ABSTRACT: Antarctic krill Euphausia superba is a key species in the Southern Ocean, where its habitat is projected to undergo continued warming and increases in pCO₂. Experiments during 2 summer field seasons at Palmer Station, Antarctica, investigated the independent and interactive effects of elevated temperature and pCO₂ (decreased pH) on feeding, growth, acid-base physiology, metabolic rate, and survival of adult Antarctic krill. Ingestion and clearance rates of chlorophyll were depressed under low pH (7.7) compared to ambient pH (8.1) after a 48 h acclimation period, but this difference disappeared after a 21 d acclimation. Growth rates were negligible and frequently negative, but were significantly more negative at high (3°C, -0.03 mm d^-1) compared to ambient temperature (0°C, -0.01 mm d^-1) with no effect of pH. Modest elevations in tissue total CO₂ and tissue pH were apparent at low pH but were short-lived. Metabolic rate increased with temperature but was suppressed at low pH in smaller but not larger krill. Although effects of elevated temperature and/or decreased pH were mostly sublethal, mortality was higher at high temperature/low pH (58%) compared to ambient temperature/pH or ambient temperature/low pH (>90%). This study identified 3 dominant patterns: (1) shorter-term effects were primarily pH-dependent; (2) krill compensated for lower pH relatively quickly; and (3) longer-term effects on krill growth and survival were strongly driven by temperature with little to no pH effect.

中文翻译：

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海洋酸化和高温对南极磷虾磷虾磷虾的摄食，生长和生理过程的综合影响

摘要：南极磷虾Euphausia superba是南大洋的重要物种，预计其栖息地将持续变暖并增加p CO ₂。在南极洲帕尔默站的两个夏季野外季节进行的实验研究了升高的温度和p CO ₂的独立和交互作用（降低的pH）对成年南极磷虾的摄食，生长，酸碱生理，代谢率和存活率的影响。在适应环境48 h后，与环境pH（8.1）相比，在低pH（7.7）下，叶绿素的摄取和清除率降低了，但是在适应21 d后，这种差异消失了。生长速率可以忽略不计，并且通常为负值，但是与环境温度（0°C，-0.01 mm d ^-1）相比，在高温度（3°C，-0.03 mm d ^-1）时，负值显着更大，而不受pH值的影响。组织总CO ₂适度升高在低pH值下组织和pH值很明显，但寿命很短。磷虾的代谢率随温度的升高而增加，但在低pH值下磷虾的代谢率却没有受到抑制。尽管升高温度和/或降低pH的影响大多是致命的，但与环境温度/ pH或环境温度/低pH（> 90％）相比，高温/低pH（58％）时死亡率更高。这项研究确定了3种主要模式：（1）短期效应主要是pH依赖性的；（2）磷虾相对较快地补偿了较低的pH；（3）温度对磷虾生长和生存的长期影响强烈，而对pH的影响很小甚至没有。