Deglacial Permafrost Organic Carbon Delivery at the Northern Svalbard Continental Margin: Insights From Tetraether Lipids and Plant Biomarkers

Degradation of Arctic permafrost due to global warming and sea level rise could trigger positive feedbacks, exacerbating climate change. However, uncertainties remain on how permafrost systems may respond because we lack a complete understanding of the permafrost‐climate feedback. Rapid warming events from the recent geological past can provide valuable insights to better constrain this feedback. Here, we present a detailed biogeochemical investigation of a marine sediment core HH11‐09GC, retrieved from the northern Svalbard continental margin. The core spans the last ∼30,000 years and includes a unit rich in permafrost‐derived organic carbon deposited during the Bølling‐Allerød interstadial. Presenting new data on tetraether lipids (branched and isoprenoid glycerol dialkyl glycerol tetraethers, GDGTs) and expanding previous investigations on CuO oxidation products (lignin phenols; Nogarotto et al., 2023, https://doi.org/10.1038/s43247‐023‐01013‐y ), we demonstrate that weakly degraded terrestrial organic matter likely advected via sea ice transport to the study site during the Bølling‐Allerød derives from Siberian Yedoma permafrost. Alteration of lignin phenols during slow lateral sediment transport and in situ production of marine GDGTs prevented us from adding information on the origin of terrestrial material delivered at the study site before and after this event. These findings highlight the potential for substantial carbon cycle perturbations following permafrost destabilization due to rising temperatures and sea levels. Our results further emphasize the necessity of a multi‐proxy approach to disentangle terrestrial carbon exports in Arctic marine environments, especially when long‐range transport occurs.