Conventionally, food web models have been developed based on the mean-field approach ignoring small-scale spatial variability. The closure modeling approach, which accounts for both fluctuations and spatial means, is an effective way to model the impact of heterogeneity on plankton ecosystem dynamics. The hypothesis “Environmental Heterogeneity (EH) supports higher trophic levels in plankton ecosystems and may sustain biodiversity” was previously proposed based on the analysis of NP, NPZ and NPZD plankton models. The present study extends previous results by analyzing a nutrient-phytoplankton-zooplankton-fish model, and finds support for the hypothesis that EH enlarges the parameter domain for stable solutions, which may promote coexistence. This study shows how top-down dynamics may influence both biomass and production ratios along the food chain, altering the trophic structure and transfer efficiency to higher trophic levels. The lower-trophic transfer efficiency (from P to Z) (TE_PZ) decreases (increases) with increasing EH in the presence (absence) of fish while higher-trophic transfer efficiency from Z to F (TE_ZF) increases with the level of heterogeneity. These results suggest that previously under-appreciated micro-scale heterogeneity may explain how the low mean-field biomass of zooplankton often observed in oligotrophic waters is able to support the growth of larval fish.

传统上，基于均值场方法开发了食物网模型，而忽略了小范围的空间变异性。考虑到波动和空间均值的封闭建模方法是一种模拟异质性对浮游生物生态系统动力学影响的有效方法。先前基于NP，NPZ和NPZD浮游生物模型的分析提出了“环境异质性（EH）支持浮游生物生态系统中较高的营养水平并可能维持生物多样性”的假设。本研究通过分析营养性浮游植物-浮游动物-鱼类模型扩展了先前的结果，并为EH的假设提供了支持扩大参数域以获得稳定的解决方案，这可能会促进共存。这项研究表明，自上而下的动力学如何影响食物链上的生物量和生产率，从而改变营养结构并提高营养效率。在鱼的存在（不存在）下，随着EH的增加，低养分的转移效率（从P到Z）（TE _PZ）降低（增加），而从Z到F的养分较高的转移效率（TE _ZF）随着鱼卵水平的增加而增加。异质性。这些结果表明，先前被低估的微观异质性可能解释了在贫营养水中经常观察到的浮游动物低平均场生物量如何能够支持幼体鱼的生长。