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arXiv 0812.4968q-bio.PEq-bio.QM
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捕食者-食饵动力学跳跃增长模型的推导及其在海洋生态系统中的应用

A jump-growth model for predator-prey dynamics: derivation and application to marine ecosystems

Samik Datta, Gustav W. Delius, Richard Law

摘要:

本文研究了海洋生态系统中生物量的动态。一个随机过程被定义为生物体在捕获和吃掉较小的生物体时经历身体大小的跳跃。利用主方程的系统展开,我们推导出宏观动力学的确定性方程,我们称之为确定性跳跃增长方程,和随机波动的线性Fokker-Planck方程。McKendrick-冯Foerster方程,在以前的研究中使用,被证明是一个一阶近似,适当的平衡系统中的捕食者比他们的猎物大得多。该模型有一个幂律的稳定状态,与海洋生态系统中经常观察到的体重对数间隔中的质量密度近似恒定一致。用数值方法比较了随机过程、确定性跳跃增长方程和McKendrick-vonFoerster方程的行为。数值分析表明,两类吸引子:稳态和行波。

英文摘要:

This paper investigates the dynamics of biomass in a marine ecosystem. A stochastic process is defined in which organisms undergo jumps in body size as they catch and eat smaller organisms. Using a systematic expansion of the master equation, we derive a deterministic equation for the macroscopic dynamics, which we call the deterministic jump-growth equation, and a linear Fokker-Planck equation for the stochastic fluctuations. The McKendrick--von Foerster equation, used in previous studies, is shown to be a first-order approximation, appropriate in equilibrium systems where predators are much larger than their prey. The model has a power-law steady state consistent with the approximate constancy of mass density in logarithmic intervals of body mass often observed in marine ecosystems. The behaviours of the stochastic process, the deterministic jump-growth equation and the McKendrick--von Foerster equation are compared using numerical methods. The numerical analysis shows two classes of attractors: steady states and travelling waves.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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