Carbon export through the Arctic rivers could significantly impact land–ocean interactions and coastal ecosystems under global warming. However, the transport dynamics and coastal fate of these carbon associated with large river plumes on the adjacent shelves remain largely unknown, particularly under large-scale climate patterns like the Arctic Oscillation (AO). In this study, we analyzed the interannual variation of particulate organic carbon (POC) and hydrological properties on the Eurasian Arctic Shelf (EAS) during summer to examine the influence of AO on the coastal dispersal of POC in the EAS. Our results revealed interannual spatial heterogeneity in highly depleted δ13CPOC values in the Laptev Sea under varying atmospheric conditions. This significant depletion of δ13CPOC could be attributed to the selective dispersal of aquatic biomass POC, coupled with rapid settlement of mineral-rich POC, as indicated by the relationship between δ13CPOC and salinity within the Lena plume. Therefore, variations in the pathways of river plumes, driven by atmospheric forcing under the annual AO regime, could not only affect the hydrological regime of the Laptev Sea but also modulate the dispersal and dynamics of POC in the EAS. Our findings are crucial for understanding the biogeochemical behavior of terrigenous POC and its impact on the future carbon cycle and coastal ecosystem in the Arctic margins, particularly in the context of recent warming and a positive trend of AO.

中文翻译：

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北极涛动控制着欧亚北极大陆架上颗粒有机碳的年际运输和归宿


在全球变暖的情况下，通过北极河流的碳输出可能会对陆地-海洋相互作用和沿海生态系统产生重大影响。然而，这些碳与相邻大陆架上的大型河流羽流相关的传输动力学和沿海命运在很大程度上仍然未知，尤其是在北极涛动 （AO） 等大尺度气候模式下。在本研究中，我们分析了夏季欧亚北极大陆架 （EAS） 颗粒有机碳 （POC） 和水文特性的年际变化，以研究 AO 对 POC 在 EAS 沿海扩散的影响。我们的结果揭示了在不同大气条件下拉普捷夫海高度贫穷的 δ13CPOC 值的年际空间异质性。δ13CPOC 的这种显着消耗可归因于水生生物质 POC 的选择性扩散，以及富含矿物质的 POC 的快速沉降，如 δ13CPOC 与勒拿羽流内盐度之间的关系所示。因此，在年度 AO 制度下，受大气强迫驱动的河流羽流路径的变化不仅会影响拉普捷夫海的水文状况，还可以调节 POC 在 EAS 中的扩散和动力学。我们的发现对于理解陆源 POC 的生物地球化学行为及其对未来碳循环和北极边缘沿海生态系统的影响至关重要，尤其是在近期变暖和 AO 积极趋势的背景下。