Submesoscale processes in the ocean vary rapidly in both space and time, and are often difficult to capture by field observations. Their dynamical connection with marine biology remains largely unknown because of the intrinsic link between temporal and spatial variations. In May 2015, satellite chlorophyll data demonstrated high concentration patches in the edge region between mesoscale eddies, which were higher than those in the cyclonic eddy core region in the northern South China Sea (NSCS). The underlying mechanisms were examined with a high-resolution physical-biological model. By tracking Lagrangian particles in the model, this study shows that the edge region between eddies is a submesoscale frontal region that is prone to intense upwelling and downwelling motions. We identified two key submesoscale mechanisms that affect nutrient transport flux significantly, submesoscale fontal dynamics and submesoscale coherent eddies. The dynamics associated with these two mechanisms were shown to be able to inject subsurface nutrients into the upper layer, generate the high chlorophyll patch, and alter phytoplankton community structure in the NSCS. This study shows the importance of submesoscale processes on phytoplankton dynamics in the NSCS and highlights the need for high-resolution observations.

海洋中的亚尺度过程在空间和时间上变化很快，而且通常很难通过实地观测来捕捉。由于时间和空间变化之间的内在联系，它们与海洋生物学的动态联系在很大程度上仍然未知。2015年5月，卫星叶绿素数据显示，中尺度涡之间边缘区域的高浓度斑块，高于南海北部气旋涡核心区（NSCS）。使用高分辨率物理生物学模型检查了潜在机制。通过跟踪模型中的拉格朗日粒子，本研究表明涡流之间的边缘区域是一个亚中尺度的锋区，容易发生强烈的上升流和下降流运动。我们确定了两个显着影响养分转运通量的关键亚尺度机制，亚尺度丰水动力学和亚尺度相干涡流。与这两种机制相关的动力学被证明能够将地下养分注入上层，产生高叶绿素斑块，并改变 NSCS 中的浮游植物群落结构。这项研究表明了亚中尺度过程对 NSCS 中浮游植物动力学的重要性，并强调了高分辨率观测的必要性。