Riverine fluxes of carbon and inorganic nutrients are increasing in virtually all large permafrost-affected rivers, indicating major shifts in Arctic landscapes. However, it is currently difficult to identify what is causing these changes in nutrient processing and flux because most long-term records of Arctic river chemistry are from small, headwater catchments draining <200 km2 or from large rivers draining >100,000 km2. The interactions of nutrient sources and sinks across these scales are what ultimately control solute flux to the Arctic Ocean. In this context, we performed spatially-distributed sampling of 120 subcatchments nested within three Arctic watersheds spanning alpine, tundra, and glacial-lake landscapes in Alaska. We found that the dominant spatial scales controlling organic carbon and major nutrient concentrations was 3–30 km2, indicating a continuum of diffuse and discrete sourcing and processing dynamics. These patterns were consistent seasonally, suggesting that relatively fine-scale landscape patches drive solute generation in this region of the Arctic. These network-scale empirical frameworks could guide and benchmark future Earth system models seeking to represent lateral and longitudinal solute transport in rapidly changing Arctic landscapes.
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机译：几乎所有受永久冻土影响的大型河流的河流碳和无机养分通量都在增加，这表明北极景观发生了重大变化。但是，目前很难确定是什么原因导致了养分加工和通量的变化，因为北极河化学的大多数长期记录是来自<200 km 2 的小型上游水源或大型河流耗水超过100,000公里 2 。这些尺度上养分源和养分的相互作用最终控制着向北冰洋的溶质通量。在这种情况下，我们对分布在阿拉斯加的高山，苔原和冰川湖景观的三个北极流域内嵌套的120个子汇水面积进行了空间分布式采样。我们发现控制有机碳和主要养分浓度的主要空间尺度是3–30 km 2 ，表明了分散和离散的采购和加工动态的连续性。这些模式在季节上是一致的，表明相对小规模的景观斑块推动了该地区北极地区的溶质生成。这些网络规模的经验框架可以指导和基准化未来的地球系统模型，以表示快速变化的北极景观中的横向和纵向溶质运移。
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