The receding of the seasonal ice cover in the Arctic due to climate change has been predicted by models to increase climate-active biogenic trace gas emissions, specifically those of dimethylsulfide (DMS). However, insufficient DMS measurements are currently available to either support or refute this hypothesis and to fully understand the various responses of oceanic DMS in a rapidly changing Arctic Ocean environment. Here, we present high-resolution surface water DMS data collected in the summer of 2014 in combination with a suite of ancillary variables including sea ice cover, salinity, and nutrients. We show that surface seawater DMS concentrations, generally below 0.5 nmol L⁻¹, remained unchanged in the Canada Basin after sea ice retreat probably due to insufficient nutrients supply to the upper mixed layer and resulting low primary production. Moreover, in the Chukchi shelf region, DMS concentrations decreased following a phytoplankton bloom due to the rapid depletion and slow resupply of nutrients. Although the DMS sea-to-air fluxes were not high from a global perspective, they increased by a factor of 4-fold after sea ice retreat in the Arctic Ocean high latitudes. This increase in DMS flux was mainly driven by increased wind speed. This work provides unique observations and insights on how surface seawater DMS and flux to the atmosphere may change in the future Arctic Ocean.

中文翻译：

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解开北冰洋西部海冰消退后地表海水 DMS 浓度和海空通量变化

模型预测，由于气候变化，北极季节性冰盖的减少会增加气候活跃的生物微量气体排放，特别是二甲基硫醚 (DMS) 的排放。然而，目前没有足够的 DMS 测量来支持或反驳这一假设，并充分了解海洋 DMS 在快速变化的北冰洋环境中的各种响应。在这里，我们展示了 2014 年夏季收集的高分辨率地表水 DMS 数据以及一系列辅助变量，包括海冰覆盖、盐度和营养成分。我们表明，表面海水 DMS 浓度通常低于 0.5 nmol L ^-1, 在海冰消退后加拿大盆地保持不变，可能是由于上层混合层的养分供应不足，导致初级产量低。此外，在楚科奇大陆架地区，由于营养物质的快速消耗和缓慢的补给，浮游植物大量繁殖后 DMS 浓度下降。尽管从全球角度来看，DMS 海空通量并不高，但在北冰洋高纬度海冰消退后，它们增加了 4 倍。DMS 通量的增加主要是由风速增加所致。这项工作提供了关于表层海水 DMS 和流入大气的通量在未来北冰洋可能如何变化的独特观察和见解。