From Air Sacs to Tissues: Oxygen Transfer and Utilization in Diving Emperor Penguins

在运动过程中，氧气必须有效地从肺部输送到工作组织。鸟类有一个独特的呼吸系统，包括气囊和肺（称为parabronchi），并有一个单向的，而不是双向的，空气流动模式。这允许吸入空气中的高比例氧气被转移到血液中，使得其可以通过心血管系统循环到组织。在像帝企鹅这样的潜水鸟类中，气囊到组织的氧气输送对潜水能力至关重要，也是使这种物种能够潜入500米以下的适应性之一。然而，氧气从气囊转移到血液以及随后氧气向组织的分布的生理机制知之甚少。帝企鹅是理想的调查这种氧级联，因为它的大身体尺寸，潜水能力，生理数据库，并为这个物种的研究技术和协议的优先发展。这项研究应该提供洞察a）鸟类氧气运输系统效率的机制，B）企鹅潜水行为的生理基础，以及企鹅适应环境变化的能力，以及c）也许，甚至设计更好的治疗策略和工具来治疗呼吸系统疾病。该项目还包括在圣地亚哥海洋世界举办的关于企鹅生物学的教育展览和讲座。海洋世界的这些教育项目面向不同的小学和高中学生群体。一名研究生也将接受培训，并参加南极生理研究。该项目将在一系列研究中研究氧气从气囊到组织的运输，这些研究是在麦克默多湾的一个孤立的潜水洞研究营地对暂时圈养的帝企鹅进行自由潜水。将通过应用气囊和/或血液中氧分压（PO 2）的背包式记录仪以及背包式心率/心搏率记录仪获得生理数据。该实验方法将为今后研究飞行和奔跑鸟类运动过程中气囊-肺-血氧传递奠定基础。该项目审查了四个主要专题：a）气囊氧分布/消耗和前后气囊之间的空气运动，B）前气囊与动脉的PO 2差异和支气管旁气体交换，c）整个潜水过程中的血氧运输和消耗，以及有氧潜水极限的性质，以及d）潜水期间静脉氧消耗模式与心率和划水努力的关系。具体的教育推广目标包括a）在圣地亚哥海洋世界的企鹅遭遇展览中展示的短视频功能，以及B）为学生露营者和海洋世界教育计划的参与者提供讲座，视频演示和课程前和课程后评估。在南极使用企鹅背包摄像机拍摄水下视频，用于展览/演示。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

During exercise, oxygen must be efficiently delivered from the lungs to the working tissues. Birds have a unique respiratory system that includes both air sacs and lungs (called parabronchi) and has a one-way, rather than bidirectional, air flow pattern. This allows a high proportion of the oxygen in inhaled air to be transferred into the blood so that it can be circulated by the cardiovascular system to the tissues. In diving birds such as the emperor penguin, the air sac-to-tissue oxygen delivery is essential to the dive capacity, and is one of the adaptations that allows this species to dive deeper than 500 meters. However, the physiological mechanisms underlying the transfer of oxygen from air sacs to blood and the subsequent distribution of oxygen to tissues are poorly understood. The emperor penguin is ideal for investigation of this oxygen cascade because of its large body size, dive capacity, physiological data base, and the prior development of research techniques and protocols for this species. This study should provide insight into a) the mechanisms underlying the efficiency of the bird oxygen transport system, b) the physiological basis of penguin dive behavior, and the ability of penguins to adapt to environmental change, and c) perhaps, even the design of better therapeutic strategies and tools for treatment of respiratory disease. The project also includes educational exhibits and lecture programs on penguin biology at SeaWorld of San Diego. These educational programs at SeaWorld have outreach to diverse groups of grade school and high school students. One graduate student will also be trained, and participate in Antarctic physiological research. This project will examine the transport of oxygen from air sacs to tissues in a series of studies with temporarily captive emperor penguins that are free-diving at an isolated dive hole research camp in McMurdo Sound. Physiological data will be obtained with application of backpack recorders for the partial pressure of oxygen (PO2) in air sacs and/or blood, and backpack heart rate/stroke rate recorders. This experimental approach will lay the groundwork for future investigations of air sac to lung to blood oxygen transfer during exercise of flying and running birds. Four major topics are examined in this project: a) air sac oxygen distribution/depletion and the movement of air between anterior and posterior air sacs, b) anterior air sac to arterial PO2 differences and parabronchial gas exchange, c) blood oxygen transport and depletion throughout dives, and the nature of the aerobic dive limit, and d) the relationship of venous oxygen depletion patterns to both heart rate and stroke effort during dives. Specific educational outreach goals include a) short video features to be displayed in the Penguin Encounter exhibit at SeaWorld of San Diego, and b) lectures, video presentations, and pre- and post-course evaluations for student campers and participants in SeaWorld's education programs. Underwater video for exhibits/presentations with be obtained with use of a penguin backpack camera in the Antarctic.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.