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Artyukhov et al. Carbon Footprints 2026, 5, 8 Page 3 of 21

are crucial for improving forecasts of changes in biogeochemical cycles within polar ecosystems undergoing
rapid transformation.

Yamal-Nenets Autonomous Okrug (YaNAO) encompasses a vast territory (over 750,000 km ), spanning
2
subarctic and arctic landscapes, including tundra, forest-tundra, northern taiga, and mountain zones in the
northern part of Western Siberia within the permafrost zone . The Yamal region represents a critical study
[17]
area for investigating SOM mineralization processes in the context of climate warming as it combines a
diversity of cryogenic soil types (Histosols, Gleysols, Cryosols), climatic trends (intensive warming is
observed in Western Siberia during spring: +0.78 °C per ten years) , and intensive anthropogenic impact
[18]
(oil and gas industry). The latter also affects the ecotoxicological condition of the soils of the region. The
intensification of anthropogenic pressure on YaNAO soils due to hydrocarbon extraction, mining and the
development of associated infrastructure (ports, pipelines, roads, etc.) may lead to the accumulation of
pollutants, including heavy metals, in the environment. In Arctic environments, permafrost governs
cryogenic mass transfer and the accumulation of substances above permafrost , which is reflected in the
[19]
vertical distribution of pollutants . The area of the present study was previously investigated very little for
[20]
background concentrations of chemical elements in soils; therefore, establishing background concentrations
of chemical elements in soils is relevant for YaNAO .
[21]

Although SOM mineralization and the ecotoxicological state of soils are often studied separately, they are
intrinsically linked in the context of anthropogenic impacts on Arctic ecosystems. Heavy metals can
significantly alter the structure and function of microbial communities [22,23] , either stimulating or inhibiting
their activity depending on the element and its concentration. Since microbial communities are the primary
drivers of SOM decomposition , a combined assessment of both labile carbon pools and contaminant load
[24]
is essential for a holistic understanding of the stability of the vast carbon stocks in permafrost-affected
soils . This study uniquely integrates these two aspects to investigate whether anthropogenic pollution in
[25]
the Yamal region acts as an additional factor that could accelerate or decelerate the mobilization of soil
carbon into the atmosphere. The research objectives are to: (1) assess the impact of temperature on SOM
mineralization and carbon release in cryogenic soils under climate change scenario conditions; (2) evaluate
the ecotoxicological status of soils in the Yamal region by determining levels of heavy metal contamination
(Sr, Pb, Zn, Co, Ni, Cr, V, As, Mn) and calculating the soil pollution index (Zc); (3) investigate the vertical
distribution of chemical elements in soil profiles to understand their redistribution processes; and (4)
determine the kinetic parameters of SOM mineralization for biogeochemical modeling.

MATERIALS AND METHODS
Sampling and study area description
The research was conducted in the YaNAO at three sites: the Lower Ob Basin, the Rai-Iz mountain massif,
and the southern part of the Yamal Peninsula [Figure 1]. The fieldwork was carried out in August 2024. Soil
samples were taken from each sampling point at the fixed depths that correspond to specific soil layers in
triplicate from different sides of the soil profile using a steel shovel, dried on site, and then transported to St.
Petersburg in sterile sealed plastic bags for further analysis.

The first study site was located in the northern part of the Lower Ob Basin, near the cities of Salekhard and
Labytnangi. The mean annual air temperature of the area is approximately -5.1 °C, and the average annual
precipitation ranges from 500 mm. The parent materials are polygenetic and polydisperse
Neopleistocene-Holocene sedimentary deposits. The vegetation cover is dominated by Betula nana,
Vaccinium uliginosum, Andromeda polifolia, shrubs of the genus Salix, and lichens of the genera Cladonia
and Cetraria. The first key site (Sal_C1) was located southwest of Salekhard in the area of a polygonal
forest-tundra plain. On this site, Albic Podzol is formed. At the second key site (Gk_C7), eutrophic Cryic