Diving Physiology and Behavior of Emperor Penguins

帝企鹅，Aptenodytes forsteri，是最优秀的鸟类潜水员和南极生态系统中的顶级掠食者。500米潜水者在出海觅食过程中的日常活动是一个生理和行为上的谜。这个项目的目的是研究帝企鹅是如何以及为什么会潜得那么深、那么久。项目检查四个主要主题的帝企鹅潜水生物学:宽容的压力,氧气储存管理、终末器官宽容的潜水氧/缺血和深潜觅食行为。这些主题与帝企鹅在南极生态系统中作为顶级捕食者的角色有关，也与潜水生理学的关键概念有关，包括减压病、氮麻醉、浅水昏迷、低氧耐受性和有氧潜水时间的延长。本文将检验以下假设：1)帝企鹅的氮麻醉和减压病的预防是通过抑制深度肺气体交换来实现的。2)浅水昏迷不会发生，因为大脑对低氧血症的耐受性更强，而且，在深潜时，由于最后上升时肺部气体交换的恢复。3)血氧储量的消耗速率是潜水深度和心率的函数。4)有氧潜水极限（ADL）反映运动肌乳酸积累的开始，而不是所有氧储存的总消耗。5)组织抗氧化能力和自由基清除酶活性的提高可以防止潜水过程中发生的常规缺血/再灌注。6)在深海中，南极银鱼（Pleuorogramma antarcum）是帝企鹅的主要猎物。除了对以下假设进行评估外，该项目还在若干领域产生了更广泛的影响，例如与外国和国内研究所和组织（例如，日本国家极地研究所、墨西哥东北调查中心、国家地理、德克萨斯大学西南医学中心和海洋世界）建立伙伴关系。参与国家地理电视纪录片将为公众提供独特的教育机会；最新技术（如血氧电极记录仪、血液采样器和小型数码相机）的发展将为本小组和其他小组未来的研究奠定基础；B15冰山对帝企鹅繁殖成功的影响将在罗斯海几个帝企鹅聚居地进行计划中的实地调查，并通过人口普查继续进行评估。

The emperor penguin, Aptenodytes forsteri, is the premier avian diver and a top predator in the Antarctic ecosystem. The routine occurrence of 500-m diver during foraging trips to sea is both a physiological and behavior enigma. The objectives of this project address how and why emperors dive as deep and long as they do. The project examines four major topics in the diving biology of emperor penguins: pressure tolerance, oxygen store management, end-organ tolerance of diving hypoxemia/ischemia, and deep-dive foraging behavior. These subjects are relevant to the role of the emperor as a top predator in the Antarctic ecosystem, and to critical concepts in diving physiology, including decompression sickness, nitrogen narcosis, shallow water blackout, hypoxemic tolerance, and extension of aerobic dive time. The following hypotheses will be tested: 1) Prevention of nitrogen narcosis and decompression sickness in emperor penguins is achieved by inhibition of pulmonary gas exchange at depth. 2) Shallow water black out does not occur because of greater cerebral hypoxemic tolerance, and, in deep dives, because of resumption of pulmonary gas exchange during final ascent. 3) The rate of depletion of the blood oxygen store is a function of depth of dive and heart rate. 4) The aerobic dive limit (ADL) reflects the onset of lactate accumulation in locomotory muscle, not total depletion of all oxygen stores. 5) Elevation of tissue antioxidant capacity and free-radical scavenging enzyme activities protect against the routine ischemia/reperfusion which occur during diving. 6) During deep dives, the Antarctic silverfish, Pleuorogramma antarcticum, is the primary prey item for emperors. In addition to evaluation of the hypotheses below, the project has broader impacts in several areas such as partnership with foreign and national institutes and organizations (e.g., the National Institute of Polar Research of Japan, Centro de Investigacioines del Noroeste of Mexico, National Geographic, the University of Texas Southwestern Medical Center, and Sea World). Participation in National Geographic television documentaries will provide unique educational opportunities for the general public; development of state-of-the-art technology (e.g., blood oxygen electrode recorders, blood samplers, and miniaturized digital cameras) will lay the groundwork for future research by this group and others; and the effects of the B15 iceberg on breeding success of emperor penguins will continue to be evaluated with population censuses during planned fieldwork at several Ross Sea emperor penguin colonies.