Abstract Climate warming is expected to destabilize permafrost carbon (PF‐C) by thaw‐erosion and deepening of the seasonally thawed active layer and thereby promote PF‐C mineralization to CO2 and CH4. A similar PF‐C remobilization might have contributed to the increase in atmospheric CO2 during deglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (Δ14C, δ13C, and lignin phenols), this study quantifies deposition of terrestrial carbon originating from permafrost in sediments from the Chukchi Sea (core SWERUS‐L2‐4‐PC1). The sediment core reconstructs remobilization of permafrost carbon during the late Allerød warm period starting at 13,000 cal years before present (BP), the Younger Dryas, and the early Holocene warming until 11,000 cal years BP and compares this period with the late Holocene, from 3,650 years BP until present. Dual‐carbon‐isotope‐based source apportionment demonstrates that Ice Complex Deposit—ice‐ and carbon‐rich permafrost from the late Pleistocene (also referred to as Yedoma)—was the dominant source of organic carbon (66 ± 8%; mean ± standard deviation) to sediments during the end of the deglaciation, with fluxes more than twice as high (8.0 ± 4.6 g·m−2·year−1) as in the late Holocene (3.1 ± 1.0 g·m−2·year−1). These results are consistent with late deglacial PF‐C remobilization observed in a Laptev Sea record, yet in contrast with PF‐C sources, which at that location were dominated by active layer material from the Lena River watershed. Release of dormant PF‐C from erosion of coastal permafrost during the end of the last deglaciation indicates vulnerability of Ice Complex Deposit in response to future warming and sea level changes.

中文翻译：

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上次冰消期末期旧永久冻土碳重新回到楚科奇海沉积物中

摘要 气候变暖预计会通过季节性解冻活动层的融化侵蚀和加深来破坏永久冻土碳（PF-C）的稳定性，从而促进 PF-C 矿化为 CO2 和 CH4。类似的 PF-C 重新激活可能导致末次盛冰期后冰消期变暖期间大气中二氧化碳的增加。本研究利用碳同位素和陆地生物标志物（Δ14C、δ13C 和木质素酚）量化了楚科奇海沉积物（核心 SWERUS-L2-4-PC1）中源自永久冻土的陆地碳沉积。沉积物岩心重建了从距今 13,000 校准年开始的阿勒罗德晚期温暖期、新仙女木期和全新世早期变暖直至距今 11,000 校准年期间永久冻土碳的再活化，并将这一时期与全新世晚期 (距今 3,650 年) 进行了比较年 BP 至今。基于双碳同位素的来源解析表明，冰复合沉积物 - 晚更新世富含冰和碳的永久冻土（也称为 Yedoma） - 是有机碳的主要来源（66 ± 8％；平均值±标准）偏差）到消冰期末期的沉积物，其通量（8.0 ± 4.6 g·m−2·year−1）是全新世晚期（3.1 ± 1.0 g·m−2·year−1）的两倍多）。这些结果与在拉普捷夫海记录中观察到的冰消晚期 PF-C 再活化一致，但与 PF-C 源形成对比，该位置的 PF-C 源主要是来自勒拿河流域的活性层物质。末次冰消期末期沿海永久冻土侵蚀释放出休眠的 PF-C，表明冰复合沉积物在应对未来变暖和海平面变化方面的脆弱性。