Micronekton are the mid-trophic level of the ecosystem and contribute to active carbon export to the deep ocean through diel vertical migrations. Better characterization of micronekton functional groups depending on relationships to environmental variables is useful for the management of marine resources, the conservation of biodiversity and a better understanding of climate change impacts. For this purpose, regionalization of global ocean into homogeneous provinces is an approach that is generating increasing interest. However, published regionalizations efforts (i) derived from environmental forcings, that do not specifically focus on micronekton and (ii) derived from acoustic backscatter, which do not allow direct estimates of micronekton biomass. Here, we propose to fill the gap between biophysical regionalizations and micronekton biomass. We notably defined biophysical biomes using global environmental variables known to affect micronekton: temperature of the epipelagic layer, temperature stratification, and net primary production (NPP). Six biophysical biomes were defined with a clustering method. A characterization of these biophysical biomes with simulated micronekton from the SEAPODYM-LMTL model displayed biome-specific relationships between biomass and the environmental variables used in the clustering (i.e. biomasses mostly structured by NPP and temperature). Biophysical biomes also displayed specific vertical structures suggested by modelled micronekton functional groups ratios. Then, a validation of biophysical biomes’ boundaries was performed to identify potential vertical structure reorganization in acoustic backscattering response from adjacent biomes. The regionalization identified homogeneous areas in terms of acoustic vertical structure, which were also different between adjacent biomes. Finally, a comparison with another biomes’ definition computed from micronekton biomasses suggested that environmental variables can account for only some of the variability of the micronekton structures.

中文翻译：

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生物物理定义省份中建模 micronekton 的全球表征


Micronekton 是生态系统的中营养级，通过 Diel 垂直迁移为向深海的活性碳输出做出贡献。根据与环境变量的关系更好地表征 micronekton 官能团有助于海洋资源管理、生物多样性保护和更好地了解气候变化影响。为此，将全球海洋区域化为同质省份是一种越来越引起兴趣的方法。然而，已发布的区域化工作 （i） 来自环境强迫，并不特别关注微小子，以及 （ii） 来自声学反向散射，不允许直接估计微小子生物量。在这里，我们建议填补生物物理区域化和微小子生物量之间的空白。我们特别使用已知影响微内克顿的全局环境变量定义了生物物理生物群落：上层温度、温度分层和净初级生产力 （NPP）。使用聚类方法定义了 6 个生物物理生物群落。使用 SEAPODYM-LMTL 模型中的模拟微 nekton 对这些生物物理生物群落的表征显示了生物量与聚类中使用的环境变量（即主要由 NPP 和温度构成的生物量）之间的生物群落特异性关系。生物物理生物群落还显示出由建模的 micronekton 官能团比率暗示的特定垂直结构。然后，对生物物理生物群落的边界进行验证，以确定来自相邻生物群落的声学反向散射响应中潜在的垂直结构重组。 区域化根据声学垂直结构确定了同质区域，这些区域在相邻生物群落之间也有所不同。最后，与根据 micronekton 生物量计算的另一个生物群落定义的比较表明，环境变量只能解释 micronekton 结构的部分可变性。