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（称为副支气管），并且有单向而不是双向的气流模式。这使得吸入空气中的大部分氧气被转移到血液中，这样它就可以通过心血管系统循环到组织中。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，这是使这个物种能够潜水深度超过500米的适应性之一。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尚不清楚。由于帝企鹅体型大、潜水能力强、生理数据丰富，以及对该物种的研究技术和方案的预先开发，帝企鹅是研究这种氧级联的理想选择。这项研究将提供以下方面的见解：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；c)甚至可能设计更好的治疗策略和治疗呼吸系统疾病的工具。该项目还包括在圣地亚哥海洋世界举办的企鹅生物学教育展览和讲座项目。海洋世界的这些教育项目已经扩展到不同群体的小学和高中学生。还将培训一名研究生，参加南极生理学研究。这个项目将在麦克默多湾的一个孤立的潜水洞研究营地，对暂时被囚禁的帝企鹅进行一系列研究，研究氧气从气囊到组织的运输。生理数据将通过使用背包记录仪获得，用于记录气囊和/或血液中的氧分压（PO2），以及背包心率/中风率记录仪。这一实验方法将为鸟类飞跑运动中气囊到肺到血氧转移的进一步研究奠定基础。本项目研究了四个主要主题：a)气囊氧气分布/消耗和前后气囊之间的空气运动，b)前气囊与动脉PO2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，d)潜水过程中静脉氧气消耗模式与心率和中风努力的关系。具体的教育推广目标包括：a)在圣地亚哥海洋世界的企鹅邂逅展览中展示短视频；b)为学生露营者和海洋世界教育项目的参与者提供讲座、视频演示和课程前后评估。在南极使用企鹅背包相机获得展览/演示的水下视频。该奖项反映了美国国家科学基金会的法定使命，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.