Data_Sheet_1_Thermoregulatory Strategies of Diving Air-Breathing Marine Vertebrates: A Review.DOCX

The aquatic habitat of marine “air-breathing” vertebrates provides a significant thermoregulatory challenge due to the high thermal conductivity of water. In addition to temperature changes across their range, air-breathing vertebrates experience temperature changes on the timescale of seconds to minutes as they perform dives to access two critical resources: air at the surface and food at depth. In response to these challenges, air-breathing vertebrates have developed morphological and physiological adaptations that align with their life histories and phylogenies and contribute to homeostasis. However, the physiological and behavioral mechanisms used to maintain thermal balance while diving is still poorly understood. The cardiovascular system is integral to the physiological responses associated with the dive response, exercise, digestion, and thermoregulation. The adjustments required to meet one physiological demand may not be compatible with another and can result in a potential conflict between the various physiological demands imposed on air-breathing divers. We reviewed the literature on thermoregulation while diving in an effort to synthesize our current understanding of the thermoregulatory strategies of diving air-breathing marine vertebrates. Studies have demonstrated that thermoregulatory strategies can involve the temporal separation of two conflicting responses, a compromise in the performance of one response over another, or coordination of synergistic responses. We hope that a review and synthesis of both laboratory and field studies will stimulate future research efforts at the intersection of thermoregulation and diving physiology. Expanding the use of physiological biologgers, particularly to understudied species, will enhance our understanding of how these animals coordinate various physiological demands to maintain homeostasis in a thermally challenging environment.

海洋“空气呼吸”脊椎动物的水生栖息环境，因水的热导率（thermal conductivity）较高，给其带来了严峻的体温调节（thermoregulation）挑战。除了其分布范围内的温度波动外，空气呼吸脊椎动物在潜水获取表层空气与深层食物这两类关键资源时，还会在数秒至数分钟的时间尺度上经历体温变化。为应对这些挑战，空气呼吸脊椎动物演化出了与自身生活史及系统发育（phylogeny）相符的形态学与生理学适应策略，以维持体内稳态（homeostasis）。然而，目前学界对其潜水期间维持体温平衡的生理与行为机制仍知之甚少。心血管系统（cardiovascular system）对于与潜水反应、运动、消化及体温调节相关的生理应答而言不可或缺。满足某一生理需求所需的调节机制，或许与另一生理需求不兼容，这可能会给空气呼吸型潜水脊椎动物带来多重生理需求间的潜在冲突。本综述梳理了潜水期间体温调节相关的研究文献，旨在整合当前学界对潜水型空气呼吸海洋脊椎动物体温调节策略的认知。已有研究表明，体温调节策略可涵盖三类方式：两类冲突应答的时间分离、两类应答间的性能取舍，或是协同应答的协调配合。我们希望，针对实验室与野外研究的综述与整合工作，能够推动体温调节与潜水生理学（diving physiology）交叉领域的未来研究发展。扩大生理生物记录仪（physiological biologgers）的应用范围，尤其是将其用于研究不足的物种，将有助于我们进一步理解这些动物如何协调多重生理需求，以在温度挑战严苛的环境中维持体内稳态。