Klymasz-Swartz Aaron K, Allen Garett J P, Treberg Jason R, Yoon Gwangseok R, Tripp Ashley, Quijada-Rodriguez Alex R, Weihrauch Dirk
University of Manitoba, Department of Biological Sciences, Winnipeg, R3T2N2, MB, Canada.
University of Manitoba, Department of Biological Sciences, Winnipeg, R3T2N2, MB, Canada.
Comp Biochem Physiol A Mol Integr Physiol. 2019 Sep;235:202-210. doi: 10.1016/j.cbpa.2019.06.005. Epub 2019 Jun 14.
The physiological consequences of exposing marine organisms to predicted future ocean scenarios, i.e. simultaneous increase in temperature and pCO, have only recently begun to be investigated. Adult American lobster (Homarus americanus) were exposed to either current (16 °C, 47 Pa pCO, pH 8.10) or predicted year 2300 (20 °C, 948 Pa pCO, pH 7.10) ocean parameters for 14-16 days prior to assessing physiological changes in their hemolymph parameters as well as whole animal ammonia excretion and resting metabolic rate. Acclimation of lobster simultaneously to elevated pCO and temperature induced a prolonged respiratory acidosis that was only partially compensated for via accumulation of extracellular HCO and ammonia. Furthermore, acclimated animals possessed significantly higher ammonia excretion and oxygen consumption rates suggesting that future ocean scenarios may increase basal energetic demands on H. americanus. Enzyme activity related to protein metabolism (glutamine dehydrogenase, alanine aminotransferase, and aspartate aminotransferase) in hepatopancreas and muscle tissue were unaltered in future ocean scenario exposed animals; however, muscular citrate synthase activity was reduced suggesting that, while protein catabolism may be unchanged, the net energetic output of muscle may be compromised in future scenarios. Overall, H. americanus acclimated to ocean conditions predicted for the year 2300 appear to be incapable of fully compensating against climate change-related acid-base challenges and experience an increase in metabolic waste excretion and oxygen consumption. Combining our study with past literature on H. americanus suggests that the whole lifecycle from larvae to adult stages is at risk of severe growth, survival and reproductive consequences due to climate change.
将海洋生物暴露于预测的未来海洋情景（即温度和pCO同时升高）的生理后果，直到最近才开始被研究。成年美洲龙虾（美洲螯龙虾）在评估其血淋巴参数的生理变化以及全动物氨排泄和静息代谢率之前，先暴露于当前（16°C，47 Pa pCO，pH 8.10）或预测的2300年（20°C，948 Pa pCO，pH 7.10）海洋参数下14 - 16天。龙虾同时适应升高的pCO和温度会引发长期的呼吸性酸中毒，这种酸中毒仅通过细胞外HCO和氨的积累得到部分补偿。此外，适应环境的动物具有显著更高的氨排泄和耗氧率，这表明未来的海洋情景可能会增加对美洲螯龙虾的基础能量需求。在暴露于未来海洋情景的动物中，肝胰腺和肌肉组织中与蛋白质代谢相关的酶活性（谷氨酰胺脱氢酶、丙氨酸转氨酶和天冬氨酸转氨酶）没有改变；然而，肌肉柠檬酸合酶活性降低，这表明虽然蛋白质分解代谢可能不变，但在未来情景中肌肉的净能量输出可能会受到影响。总体而言，适应2300年预测海洋条件的美洲螯龙虾似乎无法完全应对与气候变化相关的酸碱挑战，并经历代谢废物排泄和耗氧量的增加。将我们的研究与过去关于美洲螯龙虾的文献相结合表明，从幼虫到成年阶段的整个生命周期都因气候变化而面临严重的生长、生存和繁殖后果的风险。
