Rodríguez J, Tintoré J, Allen J T, Blanco J M, Gomis D, Reul A, Ruiz J, Rodríguez V, Echevarría F, Jiménez-Gómez F
Departamento de Ecología, Universidad de Málaga, Campus de Teatinos, 29071-Málaga, Spain.
Nature. 2001 Mar 15;410(6826):360-3. doi: 10.1038/35066560.
Phytoplankton size structure is acknowledged as a fundamental property determining energy flow through 'microbial' or 'herbivore' pathways. The balance between these two pathways determines the ability of the ecosystem to recycle carbon within the upper layer or to export it to the ocean interior. Small cells are usually characteristic of oligotrophic, stratified ocean waters, in which regenerated ammonium is the only available form of inorganic nitrogen and recycling dominates. Large cells seem to characterize phytoplankton in which inputs of nitrate enter the euphotic layer and exported production is higher. But the size structure of phytoplankton may depend more directly on hydrodynamical forces than on the source of available nitrogen. Here we present an empirical model that relates the magnitude of mesoscale vertical motion to the slope of the size-abundance spectrum of phytoplankton in a frontal ecosystem. Our model indicates that the relative proportion of large cells increases with the magnitude of the upward velocity. This suggests that mesoscale vertical motion-a ubiquitous feature of eddies and unstable fronts-controls directly the size structure of phytoplankton in the ocean.
浮游植物的大小结构被认为是决定能量通过“微生物”或“食草动物”途径流动的一个基本属性。这两条途径之间的平衡决定了生态系统在上层循环碳或将其输出到海洋内部的能力。小细胞通常是贫营养、分层海洋水域的特征，在这些水域中，再生铵是无机氮的唯一可用形式，且再循环占主导地位。大细胞似乎是浮游植物的特征，其中硝酸盐的输入进入真光层且输出产量更高。但是浮游植物的大小结构可能更直接地取决于流体动力，而不是取决于可用氮的来源。在这里，我们提出了一个经验模型，该模型将中尺度垂直运动的幅度与锋面生态系统中浮游植物的大小-丰度谱的斜率联系起来。我们的模型表明，大细胞的相对比例随着向上速度的幅度增加而增加。这表明中尺度垂直运动——涡流和不稳定锋面的一个普遍特征——直接控制着海洋中浮游植物的大小结构。
