Iodine is a critical trace element involved in many diverse and important processes in the Earth system. The importance of iodine for human health has been known for over a century, with low iodine in the diet being linked to goitre, cretinism and neonatal death. Research over the last few decades has shown that iodine has significant impacts on tropospheric photochemistry, ultimately impacting climate by reducing the radiative forcing of ozone (O₃) and air quality by reducing extreme O₃ concentrations in polluted regions. Iodine is naturally present in the ocean, predominantly as aqueous iodide and iodate. The rapid reaction of sea-surface iodide with O₃ is believed to be the largest single source of gaseous iodine to the atmosphere. Due to increased anthropogenic O₃, this release of iodine is believed to have increased dramatically over the twentieth century, by as much as a factor of 3. Uncertainties in the marine iodine distribution and global cycle are, however, major constraints in the effective prediction of how the emissions of iodine and its biogeochemical cycle may change in the future or have changed in the past. Here, we present a synthesis of recent results by our team and others which bring a fresh perspective to understanding the global iodine biogeochemical cycle. In particular, we suggest that future climate-induced oceanographic changes could result in a significant change in aqueous iodide concentrations in the surface ocean, with implications for atmospheric air quality and climate.

碘是一种重要的微量元素，参与地球系统中许多不同且重要的过程。一个多世纪以来，人们就知道碘对人类健康的重要性，饮食中的低碘与甲状腺肿、克汀病和新生儿死亡有关。过去几十年的研究表明，碘对对流层光化学有显着影响，最终通过降低臭氧 (O ₃ ) 的辐射强迫来影响气候，并通过降低受污染地区的极端 O _{3浓度来影响空气质量。}碘天然存在于海洋中，主要以碘化物和碘酸盐的形式存在。海面碘化物与O _{3的快速反应}被认为是大气中最大的气态碘单一来源。由于人为 O _3增加，这种碘的释放被认为在 20 世纪急剧增加，增加了 3 倍之多。然而，海洋碘分布和全球循环的不确定性是有效预测碘排放方式的主要限制因素其生物地球化学循环可能在未来发生变化或在过去发生变化。在这里，我们介绍了我们团队和其他人最近的结果的综合，这些结果为理解全球碘生物地球化学循环带来了新的视角。特别是，我们建议未来气候引起的海洋学变化可能导致表层海洋中碘化物浓度的显着变化，对大气空气质量和气候产生影响。