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

对于生活在上升流生态系统（如加利福尼亚海流）中的近岸海洋物种来说，人为向大气中释放二氧化碳导致的气候变化很可能诱发海洋酸化（OA）和缺氧的同步条件，而这在季节性上升流期间会加剧。虽然人们普遍认为海洋鱼类由于其酸碱调节能力而对OA具有耐受性，但最近在热带地区的研究表明，海洋鱼类的早期生命阶段可能对溶解二氧化碳（降低海水pH值）水平的升高特别敏感，因为它们的呼吸、酸碱调节和神经递质功能受到损害。低水平的溶解氧（DO）在缺氧时发生，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、低DO环境的潜在相互作用。从分子工具到整个动物生理学，这项研究将提供一个内在整合过程的深入检查。本研究将使用多应激源框架来解决OA和缺氧对温带珊瑚礁鱼类行为、生理能力和基因表达的独立和联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传递效应，因此了解这些压力源的影响对于预测未来全球鱼类种群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，以解决多种压力源的协同效应和加利福尼亚海流物种的特征，这些特征影响它们在快速变化的气候中容忍或适应海洋化学变化的能力。该项目更广泛的影响包括为4所院校的研究生和本科生提供教育机会，并通过教学增强计划为K-12学生和教师提供推广和教育活动。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具有经济价值的底栖鱼的影响的信息。该项目的目标是利用实验室和实地研究相结合的方法，检查幼年岩鱼（sebbass属）对海洋酸化和缺氧的独立和相互作用的反应。将在野外捕获岩鱼，然后在实验室中饲养4种不同的二氧化碳分压水平和4种不同的溶解氧水平，以模拟环境条件的变化。反应变量包括：(1)嗅觉能力、脑功能不对称和解决问题能力的变化测量；(2)对游泳能力、呼吸、有氧表现和生长的影响。此外，我们将使用下一代转录组测序来检测Na+/K+ atp酶（NKA）、柠檬酸合成酶（CS）和乳酸脱氢酶（LDH）的基因表达和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代谢转变的代理。海洋传感器将在现场部署，以确定加州北部和中部近岸栖息地缺氧和低pH事件的频率和强度。将对幼年岩鱼进行适应性采样，以评估原位暴露于低pH和低DO环境中的个体的基因表达和生理反应。将比较OA和缺氧对不同生活史（如幼虫期、产卵时间等）的岩鱼物种的影响，并从不同暴露于低pH/低DO事件的地区收集，以解决当地适应的可能性。这个项目的重点是在定居时早期幼年阶段的反应，因为这一阶段在一个关键时期暴露于近岸海洋化学变化中，生理压力和行为中断可能由于捕食风险的增加而对人口产生最强烈的影响。

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.