Collaborative Research: Ocean Acidification: RUI: Multiple Stressor Effects of Ocean Acidification and Hypoxia on Behavior, Physiology, and Gene Expression of Temperate Reef Fishes

对于居住在诸如加州海流等上升流生态系统中的近海岸海洋物种而言，人类活动向大气中排放二氧化碳造成的气候变化很可能导致海洋酸化（OA）和缺氧的并发状况，而这在季节性上升流期间会加剧。虽然海洋鱼类通常被认为是容忍OA由于他们的能力，在酸碱调节，最近的研究表明，在热带地区的早期生命阶段可能是特别敏感的溶解CO2（降低海水pH值）的水平升高，通过损害呼吸，酸碱调节和神经递质功能。缺氧期间出现的低水平溶解氧（DO）同样会影响海洋鱼类的行为，生理和生存。很少有研究涉及低pH值、低DO环境的潜在相互作用。从分子工具到整个动物生理学，这项研究将深入研究固有的整合过程。该研究将使用多应激源框架来解决OA和缺氧对温带珊瑚鱼行为，生理能力和基因表达的独立和综合影响所带来的潜在威胁。由于生命早期阶段的死亡率具有重要的遗留效应，因此了解这些压力因素的影响对于预测全球鱼类种群未来对气候变化的反应至关重要。这些信息将为进一步研究奠定基础，进一步研究多重压力源的协同效应以及影响加州海流物种在快速变化的气候中耐受或适应海洋化学变化的能力的特性。该项目的更广泛影响包括为4个机构的研究生和本科生提供教育机会，以及通过教学改进方案为K-12学生和教师开展外联和教育活动。研究结果将传达给渔业管理机构、海洋观测项目和科学界，以提供有关气候变化对经济上有价值的底栖鱼类影响的信息。该项目的目标是利用实验室和实地研究相结合的方法，研究幼年岩鱼（属）对海洋酸化和缺氧的独立和相互作用的生态和生理相关反应。岩鱼将在野外捕获，然后在实验室中以4种不同的pCO 2水平和4种不同的DO水平饲养，以模拟环境条件的变化。响应变量包括：（1）嗅觉能力、大脑功能不对称性和解决问题能力变化的测量，以及（2）对游泳能力、呼吸、有氧运动能力和生长的影响。 此外，我们将使用下一代转录组测序来检查基因表达和Na+/K+ ATP酶（NKA），柠檬酸合酶（CS）和乳酸脱氢酶（LDH）的酶活性的全基因组变化，作为酸碱补偿和有氧和无氧代谢之间的代谢转变的代理。将在实地部署海洋传感器，以确定北方和加州中部海岸附近栖息地缺氧和低pH值事件的频率和强度。自适应采样的少年岩鱼将被用来评估基因表达和生理反应的个人暴露在原地低pH值和低DO事件在该领域。OA和缺氧的影响将在具有不同生活史的岩鱼物种之间进行比较（例如幼虫持续时间，产卵时间等）。并从暴露于低pH/低DO事件的不同区域收集，以解决当地适应的可能性。该项目的重点是在解决时的早期少年阶段的反应，因为这一阶段是暴露于附近的海岸的海洋化学变化在一个关键时期，生理压力和行为中断可能有最强的人口影响，由于捕食的风险增加。

For near shore marine species inhabiting upwelling ecosystems such as the California Current, climate change resulting from the anthropogenic release of CO2 into the atmosphere is likely to induce concurrent conditions of ocean acidification (OA) and hypoxia, which are exacerbated during periods of seasonal upwelling. Although marine fishes have generally been presumed to be tolerant of OA due to their competence in acid-base regulation, recent studies in tropical regions suggest that early life stages may be particularly sensitive to elevated levels of dissolved CO2 (which lowers seawater pH) by impairing respiration, acid-base regulation, and neurotransmitter function. Low levels of dissolved oxygen (DO), which occur during hypoxia, can likewise impact the behavior, physiology and survival of marine fishes. Few studies have addressed the potential interactive effects of a low pH, low DO environment. From molecular tools to whole animal physiology, this research will provide an in-depth examination of an inherently integrative process. The study will use a multiple stressor framework to address the potential threats posed by the independent and combined effects of OA and hypoxia on behavior, physiological capacity, and gene expression in temperate reef fishes. Because mortality in early life stages has important carryover effects, understanding the effects of these stressors is critical for predicting future climate change responses of global fish populations. Such information will lay the groundwork for further studies that address the synergistic effects of multiple stressors and the characteristics of California Current species that influence their ability to tolerate or adapt to changes in ocean chemistry in a rapidly changing climate. Broader impacts of the project include educational opportunities for graduate and undergraduate students at 4 institutions and outreach and educational activities for K-12 students and teachers through the Teaching Enhancement Program. Results will be communicated to fisheries management agencies, oceanographic observing programs, and the science community to provide information on climate change impacts for economically valuable groundfish.The project goals are to use a combination of laboratory and field studies to examine ecologically and physiologically relevant responses of juvenile rockfish (genus Sebastes) to the independent and interactive effects of ocean acidification and hypoxia. Rockfish will be captured in the field and then reared in the lab at 4 different pCO2 levels and 4 different DO levels to simulate changes in environmental conditions. Response variables include: (1) measures of changes in olfactory capabilities, brain functional asymmetry and problem-solving ability and (2) effects on swimming capabilities, respiration, aerobic performance, and growth. In addition, we will use next generation transcriptome sequencing to examine genome-wide changes in gene expression and enzyme activity for Na+/K+ ATPase (NKA), citrate synthase (CS), and lactate dehydrogenase (LDH), as proxies for acid-base compensation and metabolic shifts between aerobic and anaerobic metabolism. Oceanographic sensors will be deployed in the field to determine the frequency and intensity of hypoxia and low pH events in near shore habitats in Northern and Central California. Adaptive sampling of juvenile rockfish will be used to evaluate gene expression and physiological responses in individuals exposed in situ to low pH and low DO events in the field. The effects of OA and hypoxia will be compared across rockfish species with different life histories (e.g. larval duration, timing of spawning, etc.) and collected from regions differing in exposure to low pH/low DO events to address the potential for local adaptation. The focus of this project is on responses of the early juvenile stage at the time of settlement, because this stage is exposed to near shore changes in ocean chemistry during a critical period where physiological stress and behavioral disruptions may have the strongest demographic effects due to increased risk of predation.