Physiological constraints in marine mammals

动物对环境变化的反应在表面上表现为它们行为的变化。生理学代表了最接近的控制以及反应的能力或局限性。生物能量学是对最终影响健康和生存的货币(能源)中这些相互作用的总和或结果的衡量。我的研究计划调查生理如何限制海洋哺乳动物对其生物或物理环境变化的反应，以及由此产生的行为和能量后果。我专门研究海洋哺乳动物，因为它们的环境对它们提出了独特的要求。最引人注目的一个方面是，它们在深海觅食，但必须返回表面呼吸。这代表了一种极端的情况，由此产生的行为体现了长期(能量平衡)和短期(氧气平衡)生理需求之间的妥协。这种二分法催生了一个基于潜在生理能力和能量成本的最佳觅食模型的整个子领域。体温调节能力也是这类动物的一个重要生理考虑因素，因为它们环境的高传导性，以及对它们作为绝缘器官和能量储备的脂肪层的相互冲突的要求。此外，潜水能力、消化能力和体温调节能力之间存在内在的生理冲突，必须根据营养状态和荷尔蒙调节的季节性能量优先顺序来解决。鉴于最近可能影响许多海洋哺乳动物猎物分布和底物稳定性的快速环境变化，理解行为反应的生理限制和能量后果变得更加关键。 我已经提出了在不久的将来进行研究调查的三个具体途径。该计划将研究(I)海洋哺乳动物潜水行为的生理控制，(Ii)潜水生理、能量收支和营养之间的季节性相互作用，以及(Iii)环境条件变化对羽足动物能量收支和生理的影响。总之，这些研究将有助于我们理解海洋哺乳动物对环境变化的能量后果、生理控制和行为反应。

The response of animals to alterations in their environment is outwardly manifest as changes in their behaviour. Physiology represents the proximate controls as well as the capacity or limitations of the response. Bioenergetics is a measure of the sum result or consequences of these interactions in a currency (energy) that ultimately impacts health and survival. My research program investigates how physiology constrains the response of marine mammals to changes in their biotic or physical environment, and the resulting behavioural and energetic consequences. I specialize in marine mammals, given the unique demands placed upon them by their environment. One of the most striking aspects is the fact that they forage at depth but must return to the surface to breathe. This represents an extreme situation where the resultant behaviour embodies a compromise between competing long-term (energy balance) and short-term (oxygen balance) physiological demands. This dichotomy has spawned an entire subfield of optimal foraging models based on underlying physiological capacity and energetic costs. Thermoregulatory capacity is also an important physiological consideration in this group of animals, given the high conductivity of their environment and the conflicting demands on their blubber layer as both an insulative organ and an energy reserve. Additionally, there are innate physiological conflicts between diving abilities, digestion, and thermoregulatory abilities that must be resolved in light of nutritional states and hormone-mediated seasonal energetic priorities. Understanding physiological limitations and energetic consequences of behavioural responses has become more critical given recent rapid environmental changes that may impact prey distribution and substrate stability of many marine mammals. I have proposed three specific avenues of research inquiry to be undertaken in the immediate future. The program will investigate (i) the physiological control of dive behaviour in marine mammals, (ii) seasonal interactions between diving physiology, energy budgets, and nutrition, and (iii) the effects of changes in environmental conditions on pinniped energy budgets and physiology. Together, these studies will contribute to our understanding of the energetic consequences, physiological controls, and behavioural responses of marine mammals to changes in their environment.