References

gesj

GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY

2071-93882542-1565

Russian Geographical Society

10.24057/2071-9388-2026-4107

gesj-4617

Research Article

RESEARCH PAPER

Статьи

Soil Organic Matter Mineralization and Transformation in Inner Shelf Oases of East Antarctica: Laboratory Assessments and Role of Environmental Drivers

Alekseev

Ivan I.

Bering str. 38A, Saint Petersburg, 199397; Pushkinskaya str. 11, Petrozavodsk, 185000

alekseevivan95@gmail.com

Grek

Elena N.

2nd line of Vasilevsky island 23, Saint Petersburg, 199004

Arctic and Antarctic Research Institute; Karelian Research Centre of the Russian Academy of ScienceRussian FederationState Hydrological InstituteRussian Federation

2026

31032026

1913650

2026

Alekseev I.I., Grek E.N.

Данная работа распространяется под лицензией Creative Commons Attribution 4.0.

This work is licensed under a Creative Commons Attribution 4.0 License.

https://ges.rgo.ru/jour/article/view/4617

Soils of ice-free regions (oases) in East Antarctica have been rarely investigated via the prism of combined detailed biological and chemical methods. The main purpose of this work is to assess the influence of environmental factors, including microrelief and local features of the accumulation of biogenic material on the mineralization and humification of the organic matter in topsoils from Bunger Hills and Schirmacher Oasis. We used multiple techniques to analyze soil basal respiration and mineralization rates, extract humic acids, and investigate their molecular structure by ¹³C-NMR spectroscopy.

The results reveal that soil formed under moss cushions exhibits the highest levels of organic carbon (up to 2.43%), alongside elevated basal respiration rates, which reached up to 2.979±0.015 mg g −1 day−1in moist conditions. Soil pH ranged from slightly acidic to alkaline, influenced by salt accumulation, which adversely affects plant communities and limits biomass production. Using 13C-NMR spectroscopy, although in a limited number of samples, we identified a predominance of aliphatic structures in humic acids with carboxylic functional groups, indicating significant vegetation influence on organic matter complexity. The sp²/sp³ carbon ratios (0.724 for Bunger Hills and 0.408 for Schirmacher Oasis) indicate a balance between potentially decomposable aliphatic and stable aromatic structures. Mineralization rates were significantly higher in soils with greater moisture retention, with cumulative CO2 release reaching up to 150 mg CO2/kg-1 soil day¯¹ over a 30-day period. Overall, our work revealed complex relationships between the environmental conditions and soil characteristics that significantly influence biological activity, carbon storage, and organic matter structure.

carbon sequestrationAntarcticsoil organic matterhumic acids13C-NMR

The authors would like to acknowledge the Russian Antarctic Expedition, Antonina Chetverova (Arctic and Antarctic Research Institute) and colleagues for their crucial help in fieldwork. The research was supported by the Russian Science Foundation (project № 24-27-00361 «Soils in Eastern Antarctica oases: biogeochemistry, stability of organic matter and environmental risks»)

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The authors declare that there are no conflicts of interest present.