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.
Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology Chinese Academy of Sciences, Changchun 130102, China.
Sci Total Environ. 2023 Apr 15;869:161864. doi: 10.1016/j.scitotenv.2023.161864. Epub 2023 Jan 28.
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 δC value of the CO 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.
矿物保护可以减缓变暖对多年冻土湿地有机碳（OC）矿化的影响，这对土壤 OC 的动态变化有重要影响。然而，多年冻土区湿地矿物土壤对变暖的响应机制尚不清楚。本研究选择了欧亚多年冻土区的南部边缘地区，采用物理分馏法对原状和重分组（HF）土壤进行室内增温培养实验。结果表明，HF 占原状土总 OC 矿化的 51.25%，HF 土壤中排放的 CO 的 δC 值高于原状土。这表明矿物土壤具有潜在的可用性，HF 中的矿化 OC 是更稳定的组分。此外，10°C 增温后矿物亚土层的矿化作用仅约为有机表土层增加的一半，温度敏感性与 Fe/Al 氧化物与 OC 比值呈显著负相关。研究结果表明，在多年冻土退化的情况下，高纬度矿物土壤的物理保护对于 OC 的稳定性至关重要，这可能会减缓多年冻土湿地成为碳源的趋势。
