Putman Nathan F, Lumpkin Rick, Sacco Alexander E, Mansfield Katherine L
Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, FL 33149, USA.
Proc Biol Sci. 2016 Dec 14;283(1844). doi: 10.1098/rspb.2016.1689.
Predictions of organismal movements in a fluid require knowing the fluid's velocity and potential contributions of the organism's behaviour (e.g. swimming or flying). While theoretical aspects of this work are reasonably well-developed, field-based validation is challenging. A much-needed study recently published by Briscoe and colleagues in Proceedings of the Royal Society B compared movements and distribution of satellite-tracked juvenile sea turtles to virtual particles released in a data-assimilating hindcast ocean circulation model. Substantial differences observed between turtles and particles were considered evidence for an important role of active swimming by turtles. However, the experimental design implicitly assumed that transport predictions were insensitive to (i) start location, (ii) tracking duration, (iii) depth, and (iv) physical processes not depicted in the model. Here, we show that the magnitude of variation in physical parameters between turtles and virtual particles can profoundly alter transport predictions, potentially sufficient to explain the reported differences without evoking swimming behaviour. We present a more robust method to derive the environmental contributions to individual movements, but caution that resolving the ocean velocities experienced by individual organisms remains a problem for assessing the role of behaviour in organismal movements and population distributions.
预测生物体在流体中的运动需要了解流体的速度以及生物体行为（如游泳或飞行）的潜在影响。虽然这项工作的理论方面已经得到了较好的发展，但基于实地的验证具有挑战性。布里斯科及其同事最近发表在《英国皇家学会学报B》上的一项急需的研究，将卫星追踪的幼年海龟的运动和分布与在数据同化后推海洋环流模型中释放的虚拟粒子进行了比较。海龟和粒子之间观察到的显著差异被视为海龟主动游泳发挥重要作用的证据。然而，实验设计隐含地假设运输预测对以下因素不敏感：（i）起始位置，（ii）追踪持续时间，（iii）深度，以及（iv）模型中未描述的物理过程。在这里，我们表明海龟和虚拟粒子之间物理参数的变化幅度可以深刻改变运输预测，这可能足以解释所报告的差异，而无需引入游泳行为。我们提出了一种更稳健的方法来推导环境对个体运动的影响，但要注意，解析个体生物体所经历的海洋速度仍然是评估行为在生物体运动和种群分布中作用的一个问题。
