Global warming has accelerated the iodine cycle in the Arctic Ocean, amplifying its significance in the global iodine cycle. However, some intricacies of the iodine cycle in the Arctic marine environment remain unclear. In this study, we present concentrations of stable- and radio-iodine (I and I) in total iodine, iodide (I), and iodate (IO) in seawater from the Beaufort, Chukchi, and Bering Seas. Results show a wide range of I/I ratios of total iodine (3.2 × 10–9.3 × 10), indicating that the total I/I ratio is a valuable fingerprint for identifying water masses and comprehending mixing processes. Iodine loss in surface seawater was quantitatively assessed using I, revealing that Arctic rivers substantially contribute to the emission of iodine into the atmosphere from the Arctic and subarctic seas. Our redox simulation in the Arctic intermediate layer shows the concentrations and I/I ratios of I and IO during its migration and provides the first evidence of an IO reduction process masked by the I oxidation in the intermediate Arctic Ocean. Oxidation and reduction processes in the intermediate Arctic Ocean were characterized by extremely slow rates, at 0.95–2.41 and 0.26 ± 0.13 nM/year, respectively. Our findings demonstrate the effectiveness of anthropogenic I in tracking iodine cycling in the Arctic marine environment.

中文翻译：

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人为碘 129 追踪北极的碘循环


全球变暖加速了北冰洋的碘循环，增强了其在全球碘循环中的重要性。然而，北极海洋环境中碘循环的一些复杂性仍不清楚。在这项研究中，我们展示了波弗特海、楚科奇海和白令海海水中总碘、碘化物 (I) 和碘酸盐 (IO) 中稳定碘和放射性碘（I 和 I）的浓度。结果显示总碘的 I/I 比率范围很广（3.2 × 10–9.3 × 10），这表明总 I/I 比率是识别水团和理解混合过程的宝贵指纹。使用I对表层海水中的碘损失进行了定量评估，结果表明北极河流在很大程度上促进了北极和亚北极海域向大气中排放碘。我们在北极中间层的氧化还原模拟显示了 I 和 IO 在其迁移过程中的浓度和 I/I 比，并提供了北冰洋中间层中 I 氧化掩盖的 IO 还原过程的第一个证据。北冰洋中部的氧化和还原过程的特点是极其缓慢的速率，分别为 0.95-2.41 和 0.26 ± 0.13 nM/年。我们的研究结果证明了人为 I 在追踪北极海洋环境中碘循环方面的有效性。