Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany.
MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520 - 630 Peniche, Portugal.
Sci Total Environ. 2021 Jul 1;776:145736. doi: 10.1016/j.scitotenv.2021.145736. Epub 2021 Feb 9.
In nature, a multitude of factors influences the fitness of an organism at a given time, which makes single stressor assessments far from ecologically relevant scenarios. This study focused on the effects of water temperature and predation stress on the metabolism and body mass gain of a common intertidal rock pool fish, Gobius paganellus, addressing the following hypotheses: (1) the energy metabolism of G. paganellus under predation stress is reduced; (2) G. paganellus shows thermal compensation under heat stress; and (3) thermal stress is the dominant stressor that may override predation stress responses. Individuals were exposed to simulated predation stress and temperature increase from 20 °C to 29 °C, and both stressors combined. Physiological effects were addressed using biochemical biomarkers related with energy metabolism (isocitrate dehydrogenase, lactate dehydrogenase, energy available, energy consumption rates), oxidative stress (superoxide dismutase, catalase, DNA damage, lipid peroxidation), and biotransformation (glutathione-S-transferase). The results of this study revealed that predation stress reduced the cellular metabolism of G. paganellus, and enhanced storage of protein reserves. As hypothesized, hyperthermia decreased the aerobic mitochondrial metabolism, indicating thermal compensation mechanisms to resist against unfavourable temperatures. Hyperthermia was the dominant stressor overriding the physiological responses to predation stress. Both stressors combined might further have synergistically activated detoxification pathways, even though not strong enough to counteract lipid peroxidation and DNA damage completely. The synergistic effect of combined thermal and predation stress thus may not only increase the risk of being preyed upon, but also may indicate extra energy trade-off for the basal metabolism, which in turn may have ecologically relevant consequences for general body functions such as somatic growth and reproduction. The present findings clearly underline the ecological importance of multi-stressor assessments to provide a better and holistic picture of physiological responses towards more realistic evaluations of climate change consequences for intertidal populations.
在自然界中，许多因素会影响生物体在特定时间的适应能力，这使得单一胁迫因素的评估远远偏离生态相关场景。本研究集中于水温和捕食胁迫对常见潮间带岩石池鱼类褐菖鲉（Gobius paganellus）代谢和体重增加的影响，提出了以下假设：（1）捕食胁迫下褐菖鲉的能量代谢会降低；（2）褐菖鲉在热应激下表现出热补偿；（3）热应激是主导胁迫因素，可能会超过捕食胁迫反应。个体暴露于模拟捕食胁迫和从 20°C 到 29°C 的温度升高，以及两者的联合胁迫下。使用与能量代谢（异柠檬酸脱氢酶、乳酸脱氢酶、可用能量、能量消耗率）、氧化应激（超氧化物歧化酶、过氧化氢酶、DNA 损伤、脂质过氧化）和生物转化（谷胱甘肽-S-转移酶）相关的生化生物标志物来解决生理效应。本研究的结果表明，捕食胁迫降低了褐菖鲉的细胞代谢，并增强了蛋白质储备的储存。正如假设的那样，高温降低了有氧线粒体代谢，表明存在热补偿机制以抵抗不利温度。高温是主导胁迫因素，超过了对捕食胁迫的生理反应。两种胁迫因素的联合可能会进一步协同激活解毒途径，尽管不足以完全抵消脂质过氧化和 DNA 损伤。因此，联合的热和捕食胁迫的协同效应不仅可能增加被捕食的风险，而且可能表明基础代谢的额外能量权衡，这反过来又可能对一般身体功能（如体细胞生长和繁殖）产生生态相关的后果。本研究结果清楚地强调了多胁迫评估的生态重要性，以提供对生理反应的更好和全面的了解，从而更真实地评估气候变化对潮间带种群的影响。
