The degradation of ice-rich permafrost deposits has the potential to release large amounts of previously freeze-locked carbon (C) and nitrogen (N) with local implications, such as affecting riverine and near-shore ecosystems, but also global impacts such as the release of greenhouse gases into the atmosphere. Here, we study the rapid erosion of the up to 27.7 m high and 1,660 m long Sobo-Sise yedoma cliff in the Lena River Delta using a remote sensing-based time-series analysis covering 53 years and calculate the mean annual sediment as well as C and N release into the Lena River. We find that the Sobo-Sise yedoma cliff, which exposes ice-rich late Pleistocene to Holocene deposits, had a mean long-term (1965–2018) erosion rate of 9.1 m yr^–1 with locally and temporally varying rates of up to 22.3 m yr^–1. These rates are among the highest measured erosion rates for permafrost coastal and river shoreline stretches. The fluvio-thermal erosion led to the release of substantial amounts of C (soil organic carbon and dissolved organic carbon) and N to the river system. On average, currently at least 5.2 × 10⁶ kg organic C and 0.4 × 10⁶ kg N were eroded annually (2015–2018) into the Lena River. The observed sediment and organic matter erosion was persistent over the observation period also due to the specific configuration of river flow direction and cliff shore orientation. Our observations highlight the importance to further study rapid fluvio-thermal erosion processes in the permafrost region, also because our study shows increasing erosion rates at Sobo-Sise Cliff in the most recent investigated time periods. The organic C and N transport from land to river and eventually to the Arctic Ocean from this and similar settings may have severe implications on the biogeochemistry and ecology of the near-shore zone of the Laptev Sea as well as for turnover and rapid release of old C and N to the atmosphere.

富含冰的永久冻土沉积物的降解有可能释放大量先前冻结锁存的碳（C）和氮（N），对当地产生影响，例如影响河流和近岸生态系统，但也影响全球影响，例如向大气中释放温室气体。在这里，我们使用基于遥感的53年时间序列分析，研究了利纳河三角洲高达27.7 m和长1,660 m的Sobo-Sise yedoma悬崖的快速侵蚀，并计算了平均年沉积量以及碳和氮释放到勒纳河。我们发现，Sobo-Sise yedoma悬崖使富含冰的晚更新世暴露于全新世沉积，其平均长期（1965-2018）侵蚀速率为910万年^–1，局部和时间变化速率最高为22.3年^–1。这些速率是永久冻土沿岸和河流海岸线延伸的最高测得的侵蚀速率之一。潮热侵蚀导致大量的碳（土壤有机碳和溶解的有机碳）和氮释放到河流系统中。平均而言，目前至少有5.2×10 ⁶ kg有机碳和0.4×10 ⁶每年（2015-2018年）公斤N被侵蚀到莉娜河中。由于河水流向和悬崖岸向的特定构造，观测到的沉积物和有机质侵蚀在观测期内仍持续存在。我们的观察结果突出了进一步研究多年冻土地区快速热流侵蚀过程的重要性，这也是因为我们的研究表明，在最近调查的时间段内，Sobo-Sise Cliff的侵蚀率正在增加。有机碳和氮从陆地到河流的运输，并最终从北美洲和北大西洋进入北冰洋，这可能对拉普捷夫海近岸地区的生物地球化学和生态学以及旧生物的周转和快速释放产生严重影响。 C和N到大气中。