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[References: 28 tit.]

Climate warming is expected to destabilize permafrost carbon (PF-C) by thaw-erosion anddeepening of the seasonally thawed active layer and thereby promote PF-C mineralization to CO2andCH4. A similar PF-C remobilization might have contributed to the increase in atmospheric CO2duringdeglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (?14C,?13C, and lignin phenols), this study quanti?es deposition of terrestrial carbon originating from permafrostin sediments from the Chukchi Sea (core SWERUS-L2-4-PC1). The sediment core reconstructsremobilization of permafrost carbon during the late Allerod warm period starting at 13,000 cal years beforepresent (BP), the Younger Dryas, and the early Holocene warming until 11,000 cal years BP and comparesthis period with the late Holocene, from 3,650 years BP until present. Dual-carbon-isotope-based sourceapportionment demonstrates that Ice Complex Deposit—ice- and carbon-rich permafrost from the latePleistocene (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 ?uxes more than twice ashigh (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 consistentwith late deglacial PF-C remobilization observed in a Laptev Sea record, yet in contrast with PF-Csources, 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 indicatesvulnerability of Ice Complex Deposit in response to future warming and sea level changes.