Ice-dominated Arctic deltas
Ice-dominated Arctic deltas
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DOI：
10.1038/s43017-022-00268-x
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发表时间：
2022-03
影响因子：
42.1
通讯作者：
I. Overeem;J. Nienhuis;A. Piliouras
中科院分区：
文献类型：
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作者：
I. Overeem;J. Nienhuis;A. Piliouras
北极三角洲构成了北极景观和海洋之间的关键界面。它们从北部永久冻土地带大约1400万平方公里的土地上过滤淡水、沉积物、碳和生化通量。本文着重介绍了影响北极三角洲的独特控制因素、季节性和地貌动力学过程。北极三角洲是“以冰为主的系统”，受到陆冰、永冻土和海冰的影响。它们具有很强的季节性，一年中有7-9个 月被冰冻。永久冻土限制了河道的迁移。北极三角洲经历了冰冻洪水，引发了与热喀斯特湖泊的生物化学交换。海冰下的运输形成了浅的前三角洲坡道。在北极，促进河流沉积物海洋改造的开阔海洋条件是短暂的。北极三角洲的数据汇编突出表明，除格陵兰三角洲外，沉积物和碳通量大大低于低纬三角洲。北极三角洲的地貌动力学也明显减弱，陆地-水的转化比低纬三角洲低约8倍，这可能是由于北极三角洲发生的独特的冰过程，这导致了优先的泛滥平原和海底沉积。未来控制因素的轨迹表明，北极三角洲将不再由冰主导。开放水域季节的扩张速度最快，预计到2100年，波浪能量将增加三倍。北极三角洲将融化，并经历更大的海浪影响，对三角洲地貌动力学和碳循环的影响鲜为人知。需要在过渡条件下进行过程研究，以进一步开发预测模型。
Arctic deltas form the critical interface between the Arctic landscape and the ocean. They filter freshwater, sediment, carbon and biochemical fluxes from approximately 14 million km2of northern permafrost terrain. This Review highlights the unique controlling factors, seasonality and morphodynamic processes affecting Arctic deltas. Arctic deltas are ‘ice-dominated systems’ that are affected by land ice, permafrost and sea ice. They are strongly seasonal and are frozen for 7–9 months of the year. Permafrost limits channel migration. Arctic deltas experience ice jam floods, inducing biochemical exchange with thermokarst lakes. Transport under sea ice creates shallow prodelta ramps. Open-ocean conditions that promote marine reworking of river deposits are short-lived in the Arctic. A data compilation of Arctic deltas highlights that sediment and carbon fluxes are substantially lower than for lower-latitude deltas, with the exception of Greenlandic deltas. Arctic delta morphodynamics are also markedly subdued, with land–water conversion about eightfold less than in low-latitude deltas, probably owing to the unique ice processes occurring in Arctic deltas, which result in preferential floodplain and submarine sedimentation. Future trajectories of controlling factors indicate that Arctic deltas will transition away from being dominated by ice. The open-water season is expanding most rapidly, with wave energy predicted to increase threefold by 2100. Arctic deltas will thaw and experience increased wave influence, with poorly understood consequences for delta morphodynamics and carbon cycling. Process studies under transitional conditions are needed to develop predictive models further.