Occurrence and stability of organic intercalation in clay minerals from permafrost-affected soils in the High Arctic – A case study from Spitsbergen (Svalbard)

Abstract

Climate warming is responsible for many environmental changes in the Arctic, which lead to the decomposition of soil organic matter (SOM) and emissions of greenhouse gases from the soil into the atmosphere. Soil minerals play a crucial role in SOM stabilization. However, little is known about the occurrence and stability of organo-mineral associations in permafrost-affected soils in the Arctic. The main aims of this study were: 1) to determine the potential occurrence of SOM within interlayers of swelling clay minerals in the permafrost-affected soils in central part of Spitsbergen (Svalbard, High Arctic) and 2) to determine resistance of the intercalated SOM within the clay minerals against thermal and chemical oxidation. The obtained results indicate that 10% to 15% of organic carbon and 30% to 45% of total nitrogen occurring in the clay fraction of the Arctic permafrost-affected soils are intercalated within the swelling clay minerals. We also report that this part of SOM is highly resistant to both chemical and thermal oxidation. These findings should be taken into consideration in the refinement of climate models and in studies concerning the thawing of permafrost, SOM mineralization, and emissions of greenhouse gases from the soil into the atmosphere.