Collaborative Research: The diving physiology of Chelonians: A comparative study of three turtle species

本项目调查海龟的潜水生理，以评估这些爬行动物适应日益严重的气候变化和污染威胁的能力，并了解渔业活动中因兼捕海龟而导致的高死亡率。海龟与其他潜水动物（如海洋哺乳动物）的不同之处在于，它们主要将氧气储存在肺部，此外，它们有一个三腔心脏，其中一个心室有选择地将血液主要分流到肺部或身体。海龟还能在长时间的休眠期存活下来，在此期间，血液缺氧，充满高浓度的乳酸。由于这种对缺氧的耐受性，目前还不清楚为什么海龟在被网缠住的短时间内死亡率如此之高。独立的生理数据记录仪将应用于一种淡水龟和两种海龟，以记录在各种条件下的心率、血氧消耗和血乳酸浓度，包括不受干扰的自发潜水和网缠。由于对肺氧的依赖，我们假设a)潜水时心率不会降低，b)潜水时血氧耗竭率与心率相关，c)不同潜水条件下心脏分流的大小和程度会有所不同，d)与大多数潜水相比，由于挣扎导致的网缠会产生高乳酸水平。该项目由斯克里普斯海洋研究所、加州大学欧文分校和东京大学（海龟研究）合作完成。该项目的更广泛影响包括培养博士后、研究生和本科生，向美国高中生推广项目，在东京大学教授潜水生理学课程，以及开发可应用于其他潜水和运动生理学研究的血乳酸传感器/记录仪。

This project investigates the diving physiology of turtles in order to assess the ability of these reptiles to adapt to increased threats of climate change and pollution, and to understand the high mortality from by-catch of marine turtles during fisheries activities. Turtles differ from other divers such as marine mammals in that they primarily store oxygen in their lungs and, in addition, have a three-chambered heart, in which a single ventricle selectively shunts blood primarily to either the lungs or the body. Turtles also survive long dormant periods, during which the blood is devoid of oxygen and filled with high concentrations of lactic acid. With this tolerance for lack of oxygen, it is unclear why there is such high mortality of marine turtles during short periods of net entanglement.Self-contained physiological data loggers will be applied to one species of freshwater turtle and two species of marine turtles in order to document heart rate, blood oxygen depletion, and blood lactate concentrations during a variety of conditions including undisturbed spontaneous dives and net entanglement. Because of the dependency on lung oxygen, it is hypothesized that a) heart rate will not decrease during dives, b) the rate of blood oxygen depletion will correlate with heart rate during dives, c) that the magnitude and degree of cardiac shunting will vary under different diving conditions, and d), in contrast to most dives, high lactate levels will occur during net entanglement due to struggling. This project features collaboration of Scripps Institution of Oceanography, the University of California Irvine and the University of Tokyo (marine turtle studies). Broader impacts of the project include training of the post-doctoral fellow, graduate students, and undergraduates, outreach programs to high school students in the United States, teaching of a class in diving physiology at the University of Tokyo, and the development of a blood lactate sensor/recorder that can be applied to other diving and exercise physiology studies in the future.