Continental margins are hot spots for iron (Fe) and manganese (Mn) cycling. In the Arctic Ocean, these depositional systems are experiencing rapid changes that could significantly impact biogeochemical cycling. In this study, we investigate whether continental margin sediments north of Svalbard represent a source or sink of Fe and Mn to the water column and how climate change might alter these biogeochemical cycles. Our results highlight that sediments on the Yermak Plateau and Sofia Basin exhibit accumulations of Fe and Mn phases compared to average shale. Conversely, sediments from the Barents Sea slope exhibit lower enrichments of Fe and Mn compared to average shale, with the exception of enriched, near‐surface sediment layers. Pore waters from these slope sites provide evidence for Fe and Mn reduction and diffusion of Fe and Mn into near surface sediments, which are susceptible to physical or biogeochemical remobilization. These regional patterns are best explained by the spatial distribution of sea ice coverage and labile organic carbon fluxes to the seafloor. As sea ice continues to retreat and the Yermak Plateau becomes seasonally ice‐free, productivity is expected to increase, which would increase the flux of carbon to the sediments, thereby increasing oxidant demand, and the reduction of Fe and Mn mineral phases. Our results suggest that as sea ice continues to retreat, the Yermak Plateau and other Arctic continental margins could become sources of Fe and Mn to Arctic bottom waters.

中文翻译：

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随着海冰撤退，北极大陆边缘沉积物可能是海水中铁和锰的来源：欧亚边缘的见解

大陆边缘是铁（Fe）和锰（Mn）循环的热点。在北冰洋，这些沉积系统正在经历迅速变化，这可能会严重影响生物地球化学循环。在这项研究中，我们调查了斯瓦尔巴德群岛以北的大陆边缘沉积物是水柱中铁和锰的来源或汇，以及气候变化如何改变这些生物地球化学循环。我们的结果表明，与平均页岩相比，Yermak高原和索非亚盆地上的沉积物表现出Fe和Mn相的积累。相反，除富集的近地表沉积物层外，与平均页岩相比，巴伦支海斜坡的沉积物显示出较低的铁和锰富集度。这些斜坡位置的孔隙水提供了铁和锰减少以及铁和锰向近地表沉积物扩散的证据，这些沉积物易于物理或生物地球化学迁移。这些区域性模式可以通过海冰覆盖的空间分布和向海底的不稳定有机碳通量来最好地解释。随着海冰继续退缩，并且Yermak高原开始季节性无冰，生产力有望提高，这将增加碳向沉积物的通量，从而增加氧化剂需求，并减少Fe和Mn矿物相。我们的结果表明，随着海冰继续退缩，Yermak高原和其他北极大陆边缘可能成为北极底部水域铁和锰的来源。这些区域性模式可以通过海冰覆盖的空间分布和向海底的不稳定有机碳通量来最好地解释。随着海冰继续退缩，并且Yermak高原开始季节性无冰，生产力有望提高，这将增加碳向沉积物的通量，从而增加氧化剂需求，并减少Fe和Mn矿物相。我们的结果表明，随着海冰继续退缩，Yermak高原和其他北极大陆边缘可能成为北极底部水域铁和锰的来源。这些区域性模式可以通过海冰覆盖的空间分布和向海底的不稳定有机碳通量来最好地解释。随着海冰继续退缩，并且Yermak高原开始季节性无冰，生产力有望提高，这将增加碳向沉积物的通量，从而增加氧化剂需求，并减少Fe和Mn矿物相。我们的结果表明，随着海冰继续退缩，Yermak高原和其他北极大陆边缘可能成为北极底部水域铁和锰的来源。这将增加碳向沉积物的通量，从而增加氧化剂需求，并减少铁和锰矿相。我们的结果表明，随着海冰继续退缩，Yermak高原和其他北极大陆边缘可能成为北极底部水域铁和锰的来源。这将增加碳向沉积物的通量，从而增加氧化剂需求，并减少铁和锰矿相。我们的结果表明，随着海冰继续退缩，Yermak高原和其他北极大陆边缘可能成为北极底水铁和锰的来源。