Number and Taxonomic Diversity of Microorganisms in the Profiles of Urban Soils in the Arctic (Murmansk)

Abstract: The chemical and microbiological properties of urban soils (Urbic Technosols) of Murmansk (Russia) are compared with those in podzols (Albic Podzols) of the background area. Urban soils display increased pH values and higher contents of major biogenic elements: C, N, P, and K, especially pronounced in subsoil horizons. In the urban topsoils, the number of cultured bacteria are increased (saprotrophs, to 3–6 × 106 CFU/g and oligotrophs, to 4.5–8 × 106 CFU/g), whereas the number of cultured microscopic fungi are decreased by two orders of magnitude (to 103 CFU) as compared with native podzols. As for the urban subsoil horizons, the number of all groups of microorganisms are increased as compared with the background. The diversity of micromycete complexes in urban soils follows the same pattern. Spatial nonuniformity of the species composition and structure of microfungal complexes is observed in the urban topsoils versus the subsoils, which display a relative uniformity of the dominant species composition (Trichocladium griseum, relative abundance of 41–77%). The share and abundance of BSL-1 and BSL-2 opportunistic micromycetes increase in the urban topsoils to 50–60% versus native podzols with the share of 30%. The degree of mycological hazard in urban soils varies from dangerous to safe (index of mycological hazard Im values are from 7–20 in the city center to 1.5–3.6 in the suburbs). The results demonstrate that urbanization in the Arctic not only changes the chemical properties of soils but also creates a new niche for microorganisms in subsoil horizons. © Pleiades Publishing, Ltd. 2024.