Millennial-aged pyrogenic carbon in high-latitude mineral soils

• Published in: Communications Earth & Environment
• Main Authors: Marcus Schiedung, Philippa Ascough, Severin-Luca Bellè, Michael I. Bird, Lisa Bröder, Negar Haghipour, Robert G. Hilton, Julie Lattaud, Samuel Abiven
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2024
• Subjects: Geology; QE1-996.5; Environmental sciences; GE1-350; permafrost
• Online Access: https://doi.org/10.1038/s43247-024-01343-5; https://doaj.org/article/2968439d6b754853a7bffb2cbf4f1f0f

Abstract Wildfires in the Arctic are producing pyrogenic carbon as product of incomplete biomass combustion. The storage and distribution of pyrogenic carbon in soils is poorly known, especially in carbon rich permafrost-affected mineral soils. Here, we extracted pyrogenic carbon in mineral soils from eleven forest sites across the North Canadian permafrost regions by hydrogen pyrolysis. We found pyrogenic carbon with millennial-scale ages that were older in continuous (1960–12,690 calibrated years before present) than in discontinuous (510–3560 calibrated years before present) permafrost-affected soils. In all cases, pyrogenic carbon showed longer residence times compared to bulk soil organic carbon. The proportions of pyrogenic carbon on total soil organic carbon were consistent at 6.9 ± 0.5% of total soil organic carbon. Thus, pyrogenic carbon forms a significant component of the total soil organic carbon and climatic as well as soil factors control the long residence times of pyrogenic carbon in vulnerable high-latitude forest mineral soils.