Department of Ocean Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA.
Department of Biology and Marine Program, Boston University, Boston, MA 02215, USA; Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, 4700 KAUST, Thuwal 23955-6900, Saudi Arabia.
J Theor Biol. 2019 Dec 7;482:109987. doi: 10.1016/j.jtbi.2019.08.018. Epub 2019 Aug 29.
The dynamics of plankton in the ocean are determined by biophysical interactions. Although physics and biotic behaviors are known to influence the observed patchiness of planktonic populations, it is still unclear how much, and if, group behavior contributes to this biophysical interaction. Here, we demonstrate how simple rules of behavior can enhance or inhibit active group cohesion in plankton in a turbulent environment. In this study, we used coral-reef fish larvae as a model to investigate the interaction between microscale turbulence and planktonic organisms. We synthesized available information on the swimming speeds and sizes of reef fish larvae, and developed a set of equations to investigate the effects of viscosity and turbulence on larvae dispersion. We then calculated the critical dispersion rates for three different swimming strategies - cruise, random-walk, and pause-travel - to determine which strategies could facilitate group cohesion during dispersal. Our results indicate that swimming strategies and migration to low-turbulence regions are the key to maintaining group cohesion, suggesting that many reef fish species have the potential to remain together, from hatching to settlement. In addition, larvae might change their swimming strategies to maintain group cohesion, depending on environmental conditions and/or their ontogenic stage. This study provides a better understanding of the hydrodynamic and biological constraints on group formation and cohesion in planktonic organisms, and reveals a wide range of conditions under which group formation may occur.
海洋浮游生物的动态是由生物物理相互作用决定的。虽然物理和生物行为已知会影响浮游种群的观察到的斑块性，但仍不清楚群体行为在多大程度上以及是否有助于这种生物物理相互作用。在这里，我们展示了简单的行为规则如何在湍流环境中增强或抑制浮游生物的主动群体凝聚力。在这项研究中，我们使用珊瑚礁鱼类幼虫作为模型来研究微尺度湍流与浮游生物之间的相互作用。我们综合了有关珊瑚礁鱼类幼虫游泳速度和大小的现有信息，并开发了一组方程来研究粘度和湍流对幼虫分散的影响。然后，我们计算了三种不同游泳策略（巡航、随机游动和暂停游动）的临界分散率，以确定哪些策略可以在分散过程中促进群体凝聚力。我们的结果表明，游泳策略和向低湍流区迁移是维持群体凝聚力的关键，这表明许多珊瑚礁鱼类物种从孵化到定居都有可能保持在一起。此外，幼虫可能会根据环境条件和/或它们的个体发育阶段改变游泳策略以维持群体凝聚力。这项研究提供了对浮游生物群体形成和凝聚力的水动力和生物学限制的更好理解，并揭示了群体形成可能发生的广泛条件。
