TY - JOUR

T1 - Deciphering the Intricate Control of Minerals on Deep Soil Carbon Stability and Persistence in Alaskan Permafrost

AU - Guo, Yi Xuan

AU - Yu, Guang Hui

AU - Hu, Shuijin

AU - Liang, Chao

AU - Kappler, Andreas

AU - Jorgenson, Mark Torre

AU - Guo, Laodong

AU - Guggenberger, Georg

N1 - Publisher Copyright: © 2024 John Wiley & Sons Ltd.

PY - 2024/10

Y1 - 2024/10

N2 - Understanding the fate of organic carbon in thawed permafrost is crucial for predicting climate feedback. While minerals and microbial necromass are known to play crucial roles in the long-term stability of organic carbon in subsoils, their exact influence on carbon persistence in Arctic permafrost remains uncertain. Our study, combining radiocarbon dating and biomarker analyses, showed that soil organic carbon in Alaskan permafrost had millennial-scale radiocarbon ages and contained only 10%–15% microbial necromass carbon, significantly lower than the global average of ~30%–60%. This ancient carbon exhibited a weak correlation with reactive minerals but a stronger correlation with mineral weathering (reactive iron to total iron ratio). Peroxidase activity displayed a high correlation coefficient (p < 10−6) with Δ14C and δ13C, indicating its strong predictive power for carbon persistence. Further, a positive correlation between peroxidase activity and polysaccharides indicates that increased peroxidase activity may promote the protection of plant residues, potentially by fostering the formation of mineral-organic associations. This protective role of mineral surfaces on biopolymers was further supported by examining 1451 synchrotron radiation infrared spectra from soil aggregates, which revealed a strong correlation between mineral OH groups and organic functional groups at the submicron scale. An incubation experiment revealed that increased moisture contents, particularly within the 0%–40% range, significantly elevated peroxidase activity, suggesting that ancient carbon in permafrost soils is vulnerable to moisture-induced destabilization. Collectively, this study offers mechanistic insights into the persistence of carbon in thawed permafrost soils, essential for refining permafrost carbon-climate feedbacks.

AB - Understanding the fate of organic carbon in thawed permafrost is crucial for predicting climate feedback. While minerals and microbial necromass are known to play crucial roles in the long-term stability of organic carbon in subsoils, their exact influence on carbon persistence in Arctic permafrost remains uncertain. Our study, combining radiocarbon dating and biomarker analyses, showed that soil organic carbon in Alaskan permafrost had millennial-scale radiocarbon ages and contained only 10%–15% microbial necromass carbon, significantly lower than the global average of ~30%–60%. This ancient carbon exhibited a weak correlation with reactive minerals but a stronger correlation with mineral weathering (reactive iron to total iron ratio). Peroxidase activity displayed a high correlation coefficient (p < 10−6) with Δ14C and δ13C, indicating its strong predictive power for carbon persistence. Further, a positive correlation between peroxidase activity and polysaccharides indicates that increased peroxidase activity may promote the protection of plant residues, potentially by fostering the formation of mineral-organic associations. This protective role of mineral surfaces on biopolymers was further supported by examining 1451 synchrotron radiation infrared spectra from soil aggregates, which revealed a strong correlation between mineral OH groups and organic functional groups at the submicron scale. An incubation experiment revealed that increased moisture contents, particularly within the 0%–40% range, significantly elevated peroxidase activity, suggesting that ancient carbon in permafrost soils is vulnerable to moisture-induced destabilization. Collectively, this study offers mechanistic insights into the persistence of carbon in thawed permafrost soils, essential for refining permafrost carbon-climate feedbacks.

KW - microbial necromass

KW - microbial residues

KW - mineral binding sites

KW - nanozyme

KW - permafrost

KW - peroxidase

KW - reactive minerals

KW - soil carbon accrual

KW - synchrotron radiation

KW - μ-FTIR

UR - http://www.scopus.com/inward/record.url?scp=85207364872&partnerID=8YFLogxK

U2 - 10.1111/gcb.17552

DO - 10.1111/gcb.17552

M3 - Article

C2 - 39450644

AN - SCOPUS:85207364872

VL - 30

JO - Global change biology

JF - Global change biology

SN - 1354-1013

IS - 10

M1 - e17552

ER -