## 3 Results and Discussion  
Soil pictures are provided in Figures 2-7. Soils of Longyugan settlement are presented in Figure 2. It is located on the first floodplain terrace of the Heigiyukha River (Longyugan), a tributary of the Nadym River. The soils of the Longyugan settlement are shown in Figure 1. The name of the settlement translates to \"river of holy spirits\" in the Khanty language. The settlement was established between 1972 and 1977 as a base for workers of the Long-Yuganskoye Linear Production Department of Main Gas Pipelines (LPUMG) as part of a large-scale program to develop the Tyumen Oil and Gas Province, aimed at exploiting the giant hydrocarbon fields of Western Siberia--Medvezhye, Urengoy, and Yamburg [30]. The creation of the settlement was driven by the need to provide logistical support for geologists, construction workers, and gas industry personnel involved in laying and maintaining main gas pipelines that connected Siberian fields to consumers in the European USSR and abroad. Initial infrastructure included temporary residential barracks, administrative buildings, warehouses, and roads. The settlement was expanded through the construction of permanent residential buildings, schools, hospitals, and social and cultural facilities between 1980 and 1990 [49]. The official population is approximately 1800. The parent materials for the Nadym-Pur area consist of sandy and sandy loams from the geochemical province of Nadym-Pur. Permafrost can be found at depths greater than 1.5 m in sandy areas, while it occurs closer to the surface in wetlands and near hydrolaccoliths. Vegetation in the Nadym region is typical of the northern taiga and forest-tundra zones, with sandy soils supporting taiga flora and loamy soils supporting forest-tundra vegetation. The mature soil is a Stagnic Albic Podzol (arenic, Siltic, Turbic) [4]. According to Russian soil taxonomy [5], this soil is a Podzol cryoturbated pseudofibric (O-Etur-BFtur-Cff). The last pedological feature is a result of the presence of spring meltwater at various depths of the soil profile and further oxidation of the iron accumulated in the form of convoluted layers. In Figure 2, from left to right, one can see how the soil morphology changes dramatically from background to recreational, residential block, and industrial areas. In the case of the recreational zone, the forest floor horizon and podzolized layer have been partially destroyed (the horizons sequence is O-AY-BF-Cff). Most likely, they were both destroyed first. Then, the forest floor recovered a little, but the podzolized horizon did not. In soils of residential (AYur-RAT-BF-C) and industrial (AYur-TCH) areas, one can see technogenic material (RAT and TCH) transported on the plot. RAT is material used for soil construction with the aim of city greening [4], TCH is transported material of any origin, but it is not used for fertile soil construction [4]. In the case of a residential plot, we can see remnants of buried topsoil of the initial Podzol. In the case of the industrial plot, transported technic materials overlap the BF--the iron illuviation horizon. In both of these soils, the soil type grows upward. Generally, in many Arctic cities, sand is piled up during economic activity, which drains the urban landscape and, to some extent, isolates the cold of permafrost. As a result, Constructozem and Technosol with buried horizons from previous soils are formed. Therefore, over the past 50 years, the Longyan settlement's soil cover and morphological structure have undergone significant changes. The soils of the Nadym region are presented in Figure 3. Nadym is a relatively old city for the Arctic territories [49; 50]. It has a long history, with a trading post established here at the beginning of the 20 th century. The city grew up on the left bank of the Nadym River in 1972, and today, its population is around 45,000. The main industry that has shaped the city is Gazprom Dobycha Nadym, accounting for around 11% of gas production in Russia.