Hillary R M, Bees M A
RRAG, Department of Environmental Science & Technology, Imperial College, London SW7 2BP, United Kingdom.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 1):031913. doi: 10.1103/PhysRevE.69.031913. Epub 2004 Mar 31.
Spatiotemporal and interspecies irregularities in planktonic populations have been widely observed. Much research into the drivers of such plankton patches has been initiated over the past few decades but only recently have the dynamics of the interacting patches themselves been considered. We take a coupled lattice approach to model continuous-in-time plankton patch dynamics, as opposed to the more common continuum type reaction-diffusion-advection model, because it potentially offers a broader scope of application and numerical study with relative ease. We show that nonsynchronous plankton patch dynamics (the discrete analog of spatiotemporal irregularity) arise quite naturally for patches whose underlying dynamics are chaotic. However, we also observe that for parameters in a neighborhood of the chaotic regime, smooth generalized synchronization of nonidentical patches is more readily supported which reduces the incidence of distinct patchiness. We demonstrate that simply associating the coupling strength with measurements of (effective) turbulent diffusivity results in a realistic critical length of the order of 100 km, above which one would expect to observe unsynchronized behavior. It is likely that this estimate of critical length may be reduced by a more exact interpretation of coupling in turbulent flows.
浮游生物种群中的时空和种间不规则性已被广泛观测到。在过去几十年里，人们针对此类浮游生物斑块的驱动因素展开了大量研究，但直到最近才开始考虑相互作用斑块本身的动态变化。与更常见的连续型反应 - 扩散 - 平流模型不同，我们采用耦合晶格方法来模拟连续时间的浮游生物斑块动态，因为它可能相对容易地提供更广泛的应用范围和数值研究。我们表明，对于其基础动态为混沌的斑块，非同步浮游生物斑块动态（时空不规则性的离散类似物）相当自然地出现。然而，我们还观察到，对于混沌区域附近的参数，不同斑块之间更容易实现平滑的广义同步，这降低了明显斑块化的发生率。我们证明，简单地将耦合强度与（有效）湍流扩散率的测量值相关联，会得出一个约为100公里的现实临界长度，超过这个长度人们预计会观察到非同步行为。通过对湍流中耦合进行更精确的解释，这个临界长度的估计值可能会降低。
