TY - JOUR

T1 - Permafrost degradation and its consequences for carbon storage in soils of Interior Alaska

AU - Liebmann, Patrick

AU - Bárta, Jiří

AU - Vogel, Cordula

AU - Urich, Tim

AU - Kholodov, Alexander

AU - Varsadiya, Milan

AU - Mewes, Ole

AU - Dultz, Stefan

AU - Waqas, Muhammad

AU - Wang, Haitao

AU - Shibistova, Olga

AU - Guggenberger, Georg

N1 - Funding Information: Open Access funding enabled and organized by Projekt DEAL. This study was funded by the Deutsche Forschungsgemeinschaft (DFG) and the Czech Science Foundation (GACR) within the framework of the Joint German-Czech Project “CRYOVULCAN—Vulnerability of carbon in Cryosols”, with the individual grants GU 406/35-1, UR 198/4-1, VO 2111/6-1, GACR project n. 20-21259J.

PY - 2024/3

Y1 - 2024/3

N2 - Permafrost soils in the northern hemisphere are known to harbor large amounts of soil organic matter (SOM). Global climate warming endangers this stable soil organic carbon (SOC) pool by triggering permafrost thaw and deepening the active layer, while at the same time progressing soil formation. But depending, e.g., on ice content or drainage, conditions in the degraded permafrost can range from water-saturated/anoxic to dry/oxic, with concomitant shifts in SOM stabilizing mechanisms. In this field study in Interior Alaska, we investigated two sites featuring degraded permafrost, one water-saturated and the other well-drained, alongside a third site with intact permafrost. Soil aggregate- and density fractions highlighted that permafrost thaw promoted macroaggregate formation, amplified by the incorporation of particulate organic matter, in topsoils of both degradation sites, thus potentially counteracting a decrease in topsoil SOC induced by the permafrost thawing. However, the subsoils were found to store notably less SOC than the intact permafrost in all fractions of both degradation sites. Our investigations revealed up to net 75% smaller SOC storage in the upper 100 cm of degraded permafrost soils as compared to the intact one, predominantly related to the subsoils, while differences between soils of wet and dry degraded landscapes were minor. This study provides evidence that the consideration of different permafrost degradation landscapes and the employment of soil fractionation techniques is a useful combination to investigate soil development and SOM stabilization processes in this sensitive ecosystem.

AB - Permafrost soils in the northern hemisphere are known to harbor large amounts of soil organic matter (SOM). Global climate warming endangers this stable soil organic carbon (SOC) pool by triggering permafrost thaw and deepening the active layer, while at the same time progressing soil formation. But depending, e.g., on ice content or drainage, conditions in the degraded permafrost can range from water-saturated/anoxic to dry/oxic, with concomitant shifts in SOM stabilizing mechanisms. In this field study in Interior Alaska, we investigated two sites featuring degraded permafrost, one water-saturated and the other well-drained, alongside a third site with intact permafrost. Soil aggregate- and density fractions highlighted that permafrost thaw promoted macroaggregate formation, amplified by the incorporation of particulate organic matter, in topsoils of both degradation sites, thus potentially counteracting a decrease in topsoil SOC induced by the permafrost thawing. However, the subsoils were found to store notably less SOC than the intact permafrost in all fractions of both degradation sites. Our investigations revealed up to net 75% smaller SOC storage in the upper 100 cm of degraded permafrost soils as compared to the intact one, predominantly related to the subsoils, while differences between soils of wet and dry degraded landscapes were minor. This study provides evidence that the consideration of different permafrost degradation landscapes and the employment of soil fractionation techniques is a useful combination to investigate soil development and SOM stabilization processes in this sensitive ecosystem.

KW - Climate change

KW - Microbial decomposition

KW - Permafrost thaw

KW - Soil development

KW - Soil fractions

KW - Soil organic matter

UR - http://www.scopus.com/inward/record.url?scp=85186885103&partnerID=8YFLogxK

U2 - 10.1007/s10533-024-01132-4

DO - 10.1007/s10533-024-01132-4

M3 - Article

AN - SCOPUS:85186885103

VL - 167

SP - 199

EP - 223

JO - BIOGEOCHEMISTRY

JF - BIOGEOCHEMISTRY

SN - 0168-2563

IS - 3

ER -