The vertical turbulent fluxes of nitrate to the base of the euphotic zone were quantified to assess the role of turbulent mixing in modulating new production inside cyclonic and anticyclonic eddies in an oligotrophic ocean. Although the turbulent nitrate flux (0.35 ± 0.11 mmol N m⁻² d⁻¹) at the base of the euphotic zone inside the cyclonic eddy was higher than that (0.07 ± 0.03 mmol N m⁻² d⁻¹) inside the anticyclonic eddy, this flux contributed to 19.7–76.3% of new production in the anticyclonic eddy and less than 4.94% in the cyclonic eddy, wherein new production was primarily driven by upwelling. Moreover, the turbulent nitrate flux in the cyclonic eddy center was higher than that at its edge because of differences in turbulent diffusivity. However, the opposite pattern appeared in the anticyclonic eddy, mainly due to discrepancies in the nitrate gradients and turbulent diffusivity. Elevated turbulent diffusivity at the edge of the anticyclonic eddy is the most likely attributed to submesoscale processes. These findings provide observatory evidence, confirming that a higher phytoplankton biomass exists in the anticyclonic eddy edge than in its center.

中文翻译：

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贫营养海洋偶极涡流湍流混合引起的硝酸盐通量

量化硝酸盐到富光区底部的垂直湍流通量，以评估湍流混合在调节贫营养海洋中气旋和反气旋涡旋内的新生产中的作用。尽管气旋涡内透光带底部的湍流硝酸盐通量（0.35 ± 0.11 mmol N m ^-2 d ^-1）高于（0.07 ± 0.03 mmol N m ^-2 d ^-1) 在反气旋涡流中，该通量在反气旋涡流中贡献了 19.7-76.3% 的新产量，在气旋涡流中贡献了不到 4.94%，其中新产量主要由上升流驱动。此外，由于湍流扩散率的差异，气旋涡中心的湍流硝酸盐通量高于其边缘。然而，反气旋涡流中出现了相反的模式，主要是由于硝酸盐梯度和湍流扩散率的差异。反气旋涡旋边缘的湍流扩散率升高最有可能归因于亚中尺度过程。这些发现提供了观测证据，证实反气旋涡旋边缘存在比其中心更高的浮游植物生物量。