Organic carbon and microbiome in tundra and forest–tundra permafrost soils, southern Yamal, Russia

• Published in: Polar Research
• Main Authors: Ivan Alekseev, Aleksei Zverev, Evgeny Abakumov
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 2021
• Subjects: arctic ecosystems; climate change; pedogenesis; soil organic carbon; soil microbial communities; yamal peninsula; Environmental sciences; GE1-350; Oceanography; GC1-1581; Arctic; Yamal Peninsula; Climate change; permafrost; Polar Research; Tundra
• Online Access: https://doi.org/10.33265/polar.v40.5283; https://doaj.org/article/5c2f4fe1591643f0a950f4072e634978

Permafrost soils differ significantly from other soils because they serve as a huge reservoir for organic carbon accumulated during the Quaternary Period, which is at risk of being released as the Arctic warms. This study aimed to characterize existing carbon pools, delineate possible mineralization risks of soil organic matter and assess microbial communities in the tundra and forest–tundra permafrost soils of the southern Yamal region of Russia. The profile distribution of carbon, nitrogen and the C:N ratio showed non-gradual changes with depth due to the manifestation of cryopedogenesis in soil profiles, which lead to cryogenic mass transfer. Mean carbon stocks for the study area were 7.85 ± 2.24 kg m−2 (0–10 cm layer), 14.97 ± 5.53 kg m−2 (0–30 cm) and 23.99 ± 8.00 kg m−2 (0–100 cm). The analysis of the humus type revealed a predominance of fulvic type and low-molecular-weight fragments in the fulvic acid fraction, which indicates high mineralization risk of humic substances under Arctic warming conditions. The taxonomic analysis of soil microbiomes revealed 48 bacterial and archaeal phyla, among which proteobacteria (27%) and actinobacteria (20%) were predominant. The pH range and nitrogen accumulation were the main environmental determinants of microbial community diversity and composition in the studied soils.