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)，并且具有单向而不是双向的气流模式。这使得吸入的空气中的高比例氧气被转移到血液中，从而可以由心血管系统循环到组织中。在像皇帝企鹅这样的潜水鸟中，气囊到组织的氧气输送对于潜水能力是必不可少的，也是允许该物种潜入500m以上深度的适应之一。然而，氧气从气囊转移到血液以及随后氧气分配到组织的生理机制还知之甚少。皇帝企鹅是研究这种氧气梯级的理想动物，因为它的体型大，潜水能力强，生理数据库，以及对该物种的研究技术和方案的先期发展。这项研究应该有助于了解a)鸟类氧气运输系统效率的潜在机制，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)甚至是设计更好的治疗策略和工具来治疗呼吸系统疾病。该项目还包括圣地亚哥海洋世界的企鹅生物学教育展品和讲座项目。海洋世界的这些教育项目面向不同的小学生和高中生群体。一名研究生也将接受培训，并参加南极生理研究。该项目将在麦克默多海湾的一个孤立的潜水洞研究营地对暂时捕获的帝企鹅进行一系列研究，以检查氧气从气囊到组织的运输。生理数据将通过应用背包记录气囊和/或血液中的氧分压(PO2)和背包心率/搏动频率记录器来获得。这一实验方法将为进一步研究飞行和奔跑鸟类运动过程中气囊到肺到血液的氧转移奠定基础。本项目主要研究四个主题：a)气囊氧气分布/耗竭和空气在前、后气囊之间的运动；b)前气囊与动脉血氧分压差和支气管旁气体交换；c)整个潜水过程中的血氧运输和耗竭，以及有氧潜水极限的性质；d)静脉氧气耗竭模式与跳水期间心率和中风努力的关系。具体的教育宣传目标包括a)在圣地亚哥海洋世界的企鹅相遇展览中展示短视频特写，以及b)为学生露营者和海洋世界教育项目的参与者提供讲座、视频演示和课程前和课程后评估。在南极洲使用企鹅背包相机获得展览/演示的水下视频。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.