Mineral protection controls soil organic carbon stability in permafrost wetlands

Yao Wang; Yuedong Guo; Xianwei Wang; Changchun Song; Yanyu Song; Zhendi Liu; Shujie Wang; Siqi Gao; Guobao Ma

doi:10.1016/j.scitotenv.2023.161864

Mineral protection controls soil organic carbon stability in permafrost wetlands

Sci Total Environ. 2023 Apr 15:869:161864. doi: 10.1016/j.scitotenv.2023.161864. Epub 2023 Jan 28.

Authors

Yao Wang¹, Yuedong Guo², Xianwei Wang³, Changchun Song⁴, Yanyu Song³, Zhendi Liu³, Shujie Wang⁵, Siqi Gao⁶, Guobao Ma⁵

Affiliations

¹ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China. Electronic address: guoyuedong@iga.ac.cn.
³ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China.
⁴ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China; School of Hydraulic Engineering, Dalian University of Technology, Dalian 116023, China.
⁵ Northeast Forestry University, Harbin 150000, China.
⁶ University of the Chinese Academy of Sciences, Beijing 100049, China.

PMID: 36720397
DOI: 10.1016/j.scitotenv.2023.161864

Abstract

Mineral protection can slow the effect of warming on the mineralization of organic carbon (OC) in permafrost wetlands, which has an important impact on the dynamics of soil OC. However, the response mechanisms of wetland mineral soil to warming in permafrost areas are unclear. In this study, the soil of the southern edge of the Eurasian permafrost area was selected, and bulk and heavy fraction (HF) soil was subjected to indoor warming incubation experiments using physical fractionation. The results showed that the HF accounted for 51.25 % of the total OC mineralization in the bulk soil, and the δ¹³C value of the CO₂ that was emitted in the HF soil was higher than that of the bulk soil. This indicates the potential availability of mineral soil and that the mineralized OC in the HF was the more stable component. Additionally, the mineralization of the mineral subsoil after warming by 10 °C was only about half of the increase in the organic topsoil, and the temperature sensitivity was significantly negatively correlated with the Fe/Al oxides to OC ratio. The results indicate that under conditions of permafrost degradation, the physical protection of mineral soil at high latitudes is essential for the stability of OC, which may slow the trend of permafrost wetlands becoming carbon sources.

Keywords: Mineral protection; Soil organic carbon; Temperature sensitivity; δ(13)C value.