大小兴安岭典型多年冻土区土壤有机碳变化的驱动因素

Driving Factors of Soil Organic Carbon Change in Typical Permafrost Regions of the Hing’an Mountains

摘要: 受全球变暖影响，多年冻土退化程度加剧，导致土壤环境发生改变。土壤有机碳在多年冻土碳动态变化过程中发挥着重要作用。大小兴安岭对冻土退化十分敏感，是中国极其重要的碳库组成部分，所以本研究选取了三个典型采样地点，探究不同冻土类型(不连续多年冻土区、零星岛状多年冻土区)和土壤深度(0~10 cm, 10~20 cm, 20~30 cm)下土壤SOC及MBC的变化情况，采用结构方程模型分析其影响因素及驱动机制。结果表明MBC含量随土壤深度增加而下降，漠河有机碳储量显著高于伊春。气候因素对冻土类型及土壤物理性质有直接影响，不同类型多年冻土区通过影响土壤物理化学性质对MBC储量有间接影响，土壤理化性质对SOC储量有直接显著影响。上述结果表明土壤MBC会随冻土类型及土壤深度的变化而变化，对环境变化十分敏感，以上研究为全球变暖下大小兴安岭土壤碳动态变化过程提供了基础数据和理论支持。

Abstract: Under the influence of global warming, permafrost degradation has intensified, resulting in changes in soil environment. Soil organic carbon plays an important role in the dynamic change of permafrost carbon. The Great and Small Hing’an Mountains are very sensitive to permafrost degradation and are an extremely important part of China’s carbon pool. Therefore, three typical sampling sites were selected in this study to explore the changes of soil SOC and MBC under different permafrost types (discontinuous permafrost area, scattered island permafrost area) and soil depths (0~10 cm, 10~20 cm, 20~30 cm). The influence factors and driving mechanism were analyzed by structural equation model. The results showed that the content of MBC decreased with the increase of soil depth, and the organic carbon storage in Mohe was significantly higher than that in Yichun. Climate factors have direct effects on the type of frozen soil and soil physical properties, different types of permafrost have indirect effects on MBC reserves through the influence of soil physical and chemical properties, and soil physical and chemical properties have direct significant effects on SOC reserves. The above results indicate that soil MBC changes with the change of permafrost type and soil depth, and is very sensitive to environmental changes. The above research provides basic data and theoretical support for the dynamic change process of soil carbon in the Great and Small Hing’an Mountains under global warming.