EJSSEurasian Journal of Soil ScienceEurasian J Soil Sci2147 - 4249Federation of Eurasian Soil Science Societieshttp://ejss.fesss.org/10.18393/ejss.183440310.18393/ejss.1834403Features of the humification process in soils of Thala Hills, Enderby land, East Antarctica: Insights from 13C-NMR spectroscopyIvan Alekseev alekseevivan95@gmail.comElena Grek 151102-1122025-06-271970-01-012025-12-022026-01-02 Copyright © 2016 The authors and Federation of Eurasian Soil Science Societies In East Antarctica, ice-free areas (oases) exhibit a wide range of environmental conditions that influence soil development. Exploring the interactions between biological and abiotic factors, along with the composition and behavior of soil organic matter, offers valuable insights into how Antarctic ecosystems react to environmental stresses. This study examined the biogeochemical characteristics and molecular composition of soil organic matter in Cryosols of the Thala Hills oasis, Enderby Land, East Antarctica. The soils studied are generally shallow, with mostly coarse textures, slightly acidic to near-neutral pH levels (from 5.40 to 6.87), and very low organic carbon content in most of the samples (TOC<1%). We used 13C CPMAS NMR spectroscopy spectroscopy to evaluate the molecular composition of humic substances extracted from typical Leptic (Lithic) Cryosol and from an ornithogenic Cryosol. Significant peaks associated with carboxylic acids (170-190 ppm) indicated that organic matter transformation processes are influenced by vegetation cover, particularly moss-lichen communities. Humification processes were observed to be more pronounced in ornithogenic soils, as indicated by the formation of humic acids with a more developed peripheral aliphatic component (outer-chain aliphatic moieties) and higher sp²/sp³ carbon ratio. These ratios indicate a balance between aliphatic content—suggesting potential for decomposition—and aromatic structures that contribute to long-term stability. Humic acids, soil organic matter, humification, Cryosols, East Antarctica, 13C-NMR spectroscopy