The biomechanics and energetics of locomotion in sea turtles: understanding the influence of load carrying on performance

海龟拥有脊椎动物中最独特的身体结构。海龟出现在2.2亿年前的化石记录中。海龟在脊椎动物中是独一无二的，因为它们的整个身体都包裹在坚硬的骨壳中，由甲壳和板壳组成，以保护自己免受捕食者的侵害。它们的壳似乎限制了它们的生活；然而，海龟栖息在一系列水生和陆地栖息地，许多物种有效地在两者之间移动（2,3）。我们将整合生物学、生物力学和生理学技术，从有机体到细胞水平整理三种海龟的能量学数据(4)。我们选择了海龟，因为它们对不同负载的专业化程度不同(5)，提供了一个广泛的范围，这将使我们更好地了解海龟的运动性能，在不断变化的环境中进行权衡，以及限制对它们在盒子里生活的影响。研究海龟将为今后研究功能多样性、适应和进化提供重要的模型。水和空气是生物必须生存和移动的流体介质，这些环境之间的物理差异（密度、粘度、重力负荷）可能对海龟等经常在水生和陆地环境之间穿梭的生物的适应和表现产生重要影响。这些陆地生物群落之间的基质也存在关键差异。我们将在机体水平上确定负重如何影响运输代谢成本和运动生物力学的差异，并使用肌肉骨骼计算模型研究环境变化背景下海龟最终在生理上限制运动表现的适应性。

Turtles have the most distinctive body plans of vertebrates (1). Turtles appear in the fossil record over 220 million years ago. Turtles are unique among vertebrates in that their whole body is enclosed within a rigid bony shell, composed of the carapace and plastron, that protects from predators. Their shells would appear to constrain their lives; however, turtles inhabit a range of both aquatic and terrestrial habitats and many species effectively move between both (2,3). We will integrate biological, biomechanical and physiological techniques to collate energetics data across three turtle species at the organismal down to the cellular level (4). We have selected sea turtles as they vary in their degree of specialisation to different loads(5) to provide a broad range that will allow us to better understand turtle locomotor performance, the trade-offs in changing environments and the impact of constraints on their life in a box. Studying turtles will provide an important model for future research on functional diversity, adaptation and evolution. Water and air represent the fluid media in which organism must survive and move and the physical disparities (density, viscosity, gravitational load) between these environments can have important consequences for adaptation and performance of organisms like turtles that routinely transverse between aquatic and terrestrial environments. There are key differences in substrate between these terrestrial biomes as well. We will determine how load bearing influences differences in the metabolic cost of transport and locomotor biomechanics at the organismal level and investigate using musculoskeletal computational models the adaptations that ultimately physiologically constrain locomotor performance in sea turtles in the context of environmental change.