The Degree of Permafrost Degradation Determines the Stability of Soil Organic Matter

Summary

This laboratory incubation study examined how permafrost degradation affects soil organic matter (SOM) stability in the Daxing'an Mountains by comparing continuous and isolated patchy permafrost zones. Findings indicate that SOM in degraded patchy permafrost is more bioavailable and temperature-sensitive (Q10 = 4.24) than in continuous permafrost, and that the protective effect of mineral-organic associations (Fe/Al oxides bound to carbon) substantially reduces temperature sensitivity of decomposition and delays transition of peatlands from carbon sinks to sources.

Regional applicability

This study is geographically specific to Chinese permafrost regions (Daxing'an Mountains) and may have limited direct applicability to United Kingdom conditions, which lack extensive permafrost zones. However, findings on mineral protection of soil organic matter and temperature sensitivity of decomposition are relevant to UK soil carbon management and may inform climate resilience strategies in other northern regions with degrading permafrost.

Key measures

Soil organic carbon (SOC), microbial biomass carbon (MBC), Fe and Al oxide content, δ¹³C isotope composition, carbon mineralisation rate, temperature sensitivity (Q10), ratio of Fe/Al oxides to organic carbon

Outcomes reported

The study measured soil organic carbon (SOC), microbial biomass carbon (MBC), Fe and Al oxide content, and carbon mineralisation rates in permafrost soils at different degradation stages under laboratory incubation at 5 and 15 °C over 89 days. Key findings include differential temperature sensitivity of carbon decomposition between soil types and the protective effect of mineral-organic associations on SOM stability.

Topic tags