The vertical variability in the oxygen minimum zone (OMZ) in the eastern South Pacific (ESP; 0–40°S) is characterized by the influence of anticyclonic intrathermocline eddies (ITEs), which are subsurface‐intensified mesoscale features that are frequently generated in the coastal upwelling zone off Peru and Chile. The unique lens‐shaped signatures that ITEs leave on temperature, salinity, and dissolved oxygen vertical distributions are used as proxies to assess their influences on vertical OMZ boundaries and thickness. Data from in situ profiles in the region (World Ocean Database and Argo databases) are used in correlation analyses between anomalous depths (and vertical displacements) of oxyclines and isopycnals/isotherms, together with an objective eddy detection method based on satellite altimetry to identify the location of such profiles (i.e., outside or inside cyclonic and anticyclonic eddies). The results indicate that most of the vertical fluctuations in the climatological OMZ have a lens‐shaped signature and that those at the mesoscale are largely due to ITEs. ITEs are a main driver of the upper oxycline variability in the coastal band, the coastal transition zone (CTZ, 3–10° from the coast) and beyond at mid‐latitudes (12–26°S). The influence of ITEs on the upper and lower oxycline variability is mostly observed within the horizontal (offshore) climatological boundary of the OMZ, suggesting that ITEs play a role in the OMZ offshore extension in the ESP. ITEs may produce mesoscale variations in the thickness of the surface‐oxygenated layer, resulting in potential changes in prey‐predator interactions and in food web functioning.

中文翻译：

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南太平洋东部最小氧气区边界的中尺度变率：热线内涡流的影响

南太平洋东部（ESP； 0–40°S）的最小氧气区（OMZ）的垂直变化特征是反气旋内热旋涡（ITEs）的影响，这些旋涡是地下强化的中尺度特征，通常在大气中产生秘鲁和智利外的沿海上升带。ITEs在温度，盐度和溶解氧垂直分布上留下的独特的透镜形特征被用作评估其对垂直OMZ边界和厚度的影响的代表。来自该地区原位剖面的数据（世界海洋数据库和Argo数据库）被用于氧化层和等深线/等温线的异常深度（和垂直位移）之间的相关分析，以及基于卫星测高的客观涡流检测方法，以识别此类配置文件的位置（即，旋风和反旋风涡旋的内部或外部）。结果表明，气候OMZ的大部分垂直波动具有透镜状特征，而中尺度的波动主要是由ITEs引起的。ITEs是沿海带，沿海过渡带（CTZ，距海岸3-10°）及中纬度（12-26°S）以外地区上层高压层变化的主要驱动力。在OMZ的水平（近海）气候边界内，通常观察到ITEs对上部和下部土层高压线变异性的影响，这表明ITEs在ESP的OMZ海上扩展中发挥了作用。ITEs可能会在表面氧化层的厚度上产生中尺度变化，从而导致猎物与食肉动物之间的相互作用以及食物网功能的潜在变化。结果表明，气候OMZ的大部分垂直波动具有透镜状特征，而中尺度的波动主要是由ITEs引起的。ITEs是沿海带，沿海过渡带（CTZ，距海岸3-10°）及中纬度（12-26°S）以外地区上层高压层变化的主要驱动力。在OMZ的水平（近海）气候边界内，通常观察到ITEs对上部和下部土层高压线变异性的影响，这表明ITEs在ESP的OMZ海上扩展中发挥了作用。ITEs可能会在表面氧化层的厚度上产生中尺度变化，从而导致猎物与食肉动物之间的相互作用以及食物网功能的潜在变化。结果表明，气候OMZ的大部分垂直波动具有透镜状特征，而中尺度的波动主要是由ITEs引起的。ITEs是沿海带，沿海过渡带（CTZ，距海岸3-10°）及中纬度（12-26°S）以外地区上层高压层变化的主要驱动力。在OMZ的水平（近海）气候边界内，通常观察到ITEs对上部和下部土层高压线变化的影响，这表明ITEs在ESP的OMZ海上扩展中发挥了作用。ITEs可能会在表面氧化层的厚度上产生中尺度变化，从而导致猎物与食肉动物之间的相互作用以及食物网功能的潜在变化。