The magnitude of natural oceanic dissolved oxygen (DO) variability remains poorly understood due to the short duration of the observational record. Here we present a high-resolution (4–9 years) reconstruction of the Southern California oxygen minimum zone (OMZ) through the Common Era using redox-sensitive metals. Rapid OMZ intensification on multidecadal timescales reveals greater DO variability than observed in instrumental records. An anomalous interval of intensified OMZ between 1600–1750 CE contradicts the expectation of better-ventilated mid-depth North Pacific during cool climates. Although the influence of low-DO Equatorial Pacific Intermediate Water on the Southern California Margin was likely weaker during this interval, we attribute the observed rapid deoxygenation to reduced North Pacific Intermediate Water (NPIW) ventilation. NPIW ventilation thus appears very sensitive to atmospheric circulation reorganization (e.g., a weakened Siberian High and Aleutian Low). In addition to temperature-induced gas solubility, atmospheric forcing under future anthropogenic influences could amplify OMZ variability.

中文翻译：

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小冰河时代重组的大气环流导致南加州快速脱氧

由于观测记录的持续时间很短，自然海洋溶解氧 (DO) 变化的幅度仍然知之甚少。在这里，我们展示了使用氧化还原敏感金属对整个共同时代南加州最低氧区 (OMZ) 进行的高分辨率（4-9 年）重建。数十年时间尺度上的快速 OMZ 强化揭示了比仪器记录中观察到的更大的 DO 变异性。公元 1600 年至 1750 年之间 OMZ 的异常强化间隔与凉爽气候期间北太平洋中部通风更好的预期相矛盾。尽管在此间隔期间，低 DO 赤道太平洋中级水对南加州边缘的影响可能较弱，但我们将观察到的快速脱氧归因于北太平洋中级水 (NPIW) 通风减少。因此，NPIW 通风似乎对大气环流重组非常敏感（例如，西伯利亚高压和阿留申低压减弱）。除了温度引起的气体溶解度外，未来人为影响下的大气强迫可能会放大 OMZ 的变异性。