【摘要】 为探究影响海洋生态系统稳定性的空间驱动因素,本文在生态系统层面上构建了一类综合考虑海洋生物生长、代谢、繁殖、死亡以及扩散和适应度趋化性粒径谱模型.利用傅里叶分析、稳定性分析等相关理论,研究了模型的平衡解以及影响系统稳定性的空间因素.通过参数估计和基于傅里叶变换的数值模拟,结果表明,扩散对系统起到了稳定性的作用,而适应度趋化性起到了不稳定的作用,二者具有明显的非对称性,且前者占据主导地位.当平衡解失稳时,系统会出现随时间变化的空间模式,尤其是在时间方向呈现行波解.结果揭示适应度趋化性可能是构成海洋生态系统空间模式的一种重要机制.更多还原

【Abstract】 For the aim of exploring spatial drivers of instability in marine ecosystems,we augmented the size-spectrum model to the ecosystem level,which synthetically takes fish’s growth,maintenance,reproduction and mortality into account,and further extended it with a random motion-diffusion,and a directed movement in the direction of increased fitnesswhich we call ’fitness taxis’.Making use of the Fourier analyses and stability analyses,we derived the equilibrium and discussed what effects these spatial movements have on the stability of marine ecosystem.Through the parameter estimations and numerical simulations based on the Fourier transform,results show that diffusion always plays a stabilizing role whereas fitness taxis destabilizes the system.There is a strong asymmetry between fitnessinduced destabilizing and diffusion-induced stabilizing effects with the latter dominating over the former.The loss of the equilibrium stability leads to the non-stationary spatially inhomogeneity,which are travelling in size.We can conclude that fitness taxis may be a remarkable underlying mechanism for pattern formations.更多还原