Pushing the Envelope of Hypoxemia: Blood Oxygen Depletion in Elephant Seals

突破低氧血症的极限：象海豹的血氧耗尽

• 批准号: 0641801
• 负责人: Paul Ponganis
• 金额: $ 25.05万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-15 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0641801&HistoricalAwards=false
• 关键词: Pushing; Envelope; Hypoxemia; Blood; Oxygen

The elephant seal is the premier diver among seals and sea lions; it routinely holds its breath for 20 minutes as it dives to depths greater than 400 meters. This project investigates the physiology that allows this seal to make such remarkable dives. In particular, it is hypothesized that these seals can withstand extremely low levels of oxygen, and that this allows them to almost completely deplete their blood of oxygen during diving. Such extreme tolerance to low levels of oxygen is beyond that found in any mammal, and well below the oxygen levels found in humans attempting to climb Mt Everest without supplemental oxygen. In order to examine this hypothesis, seals will be equipped with backpack oxygen recorders which will provide a profile of the oxygen pressure in the blood as the seal dives. It is expected that the oxygen levels in the blood will be near zero by the end of the dive, and that it is this nearly complete utilization of the blood oxygen which allows elephant seals to dive as well as they do. This study will establish the physiological limits to which these seals push themselves. This is relevant to their ability to successfully find prey underwater and to their overall ecology in an environment that may be changing due to over fishing and global warming. In addition, the mechanisms which allow the seals to tolerate such low oxygen levels may be relevant to our understanding and treatment of various pathological states in humans in which tissues are exposed to inadequate oxygen or blood flow (hypoxemia or ischemia). Lastly, in addition to involving students directly in the research, this project will develop an educational website which will provide behavioral and physiological information on deep-diving whales, seals, penguins, and sea turtles.

象海豹是海豹和海狮中首屈一指的潜水者。当它潜入400米以上的深度时，它通常会屏住呼吸20分钟。 该项目研究了这种海豹能够进行如此出色的潜水的生理机能。特别是，据推测，这些海豹可以承受极低水平的氧气，这使得它们在潜水期间几乎完全耗尽血液中的氧气。 这种对低氧水平的极端耐受性超出了任何哺乳动物的承受能力，也远低于人类在没有补充氧气的情况下攀登珠穆朗玛峰的氧水平。 为了检验这一假设，海豹将配备背包式氧气记录仪，该记录仪将在海豹潜水时提供血液中的氧气压力曲线。 预计潜水结束时血液中的氧气含量将接近于零，正是这种几乎完全利用血液中的氧气使得象海豹能够出色地潜水。 这项研究将确定这些海豹将自身推向的生理极限。 这与它们在水下成功寻找猎物的能力有关，也与它们在可能因过度捕捞和全球变暖而发生变化的环境中的整体生态有关。 此外，允许海豹耐受如此低氧气水平的机制可能与我们对人体组织暴露于氧气或血流不足（低氧血症或缺血）的各种病理状态的理解和治疗有关。 最后，除了让学生直接参与研究之外，该项目还将开发一个教育网站，提供有关深潜鲸鱼、海豹、企鹅和海龟的行为和生理信息。