D.A. Sarzhanov

Bio: D.A. Sarzhanov is an academic researcher from Peoples' Friendship University of Russia. The author has contributed to research in topics: Medicine & Steppe. The author has an hindex of 3, co-authored 3 publications receiving 40 citations. Previous affiliations of D.A. Sarzhanov include Russian State Agricultural University.

Carbon stocks and CO2 emissions of urban and natural soils in Central Chernozemic region of Russia

Abstract: C-sequestration, as a function of soils, is known to help mitigate climate change. However, the potential of urban soils to be C-sinks or sources, is widely unknown. This study aims to understand the role and significance of urban soils in the C-balance of the region. It reveals several important findings about the C-balance capacities of urban soils and the multiple factors affecting this balance. This two-year study focused on soil organic carbon (SOC) stocks and CO 2 emissions of urban soils in the city of Kursk, located in the Central Chernozemic region of Russia, an area known to have some of the most fertile soils in the world. SOС stocks and emissions were studied in residential, recreational, and industrial functional zones and in comparison to corresponding natural reference soils to analyze the influence of urbanization on C turnover Urban soils were found to store 20 to 50 kg С m − 2 in 1.5 m layer; 10–30% less than in corresponding natural Luvic Chernozems and Chernic Phaeozems, but greater than what has been reported for many other cities. The urban soils with developed cultural layers stored more C in subsoil compared to the natural soils. Emissions of CO 2 in urban soils, however, were higher than from Chernic Phaeozems but comparable to those from Luvic Chernozems. The CO 2 /SOC stocks ratio in urban soils was two–three times higher than in natural soils. These outcomes point to the intensive C turnover and low sustainability of SOC stocks in urban soils. This study found evidence that the recent urbanization of the Chernozemic region has adversely affected the C balance. Natural soils in the region are important C sinks, however they can convert to C sources in result of urbanization.

Short-term dynamics and spatial heterogeneity of CO 2 emission from the soils of natural and urban ecosystems in the Central Chernozemic Region

Abstract: A comparative analysis of the spatial-temporal trends in the emission of CO2 from soils of different functional zones of the city of Kursk, a dark gray soil of an oak forest, and a typical steppe chernozem has been performed. The averaged CO2 emission from the urban soils is 25% higher than that from the natural soils (32.1 ± 17.8 and 17.8 ± 10.2 g CO2/m2 daily, respectively). The spatial heterogeneity of the CO2 emission is also significantly higher for the urban soils, while variation in temporal dynamics of soil respiration among the studied ecosystems was insignificant.

Polycyclic Aromatic Hydrocarbon-Degrading Bacteria in Three Different Functional Zones of the Cities of Moscow and Murmansk

Abstract: We performed a comparative study of the total bacterial communities and communities of cultivable polycyclic aromatic hydrocarbons (PAH)-degrading bacteria in different functional zones of Moscow and Murmansk that were formed under the influence of the PAH composition in road and leaf dust. The PAHs were determined by high-performance liquid chromatography (HPLC); the bacterial communities’ diversity was assessed by metabarcoding. The degraders were isolated by their direct plating on a medium with the PAHs. The PAH total quantity declined in the leaf dust from the traffic to the recreational zone. For the road dust, a negative gradient with pollution was observed for Rhodococcus and Acinetobacter degraders and for their relative abundance in the microbiome for the functional zones of Moscow. The opposite effect was observed in the Murmansk leaf dust for the Rothia and Pseudomonas degraders and in the Moscow road dust for Microbacterium. The PCA and linear regression analyses showed that the Micrococcus degraders in the dust were sensitive to anthropogenic pollution, so they can be used as a tool for monitoring anthropogenic changes in the biosphere. The data on the degraders’ and microbial communities’ diversity suggest that minor degrading strains can play a key role in PAH degradation.

Urban soils as hot spots of anthropogenic carbon accumulation: Review of stocks, mechanisms and driving factors

Abstract: Department of Landscape Design and Sustainable Ecosystems, Agrarian‐ Technological Institute, RUDN University, Miklukho‐Maklaya str., 6, Moscow, Russia Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Göttingen, Büsgenweg 2, Göttingen, Germany Correspondence V. Vasenev, Department of Landscape Design and Sustainable Ecosystems, Agrarian‐ Technological Institute, RUDN University, Miklukho‐Maklaya str., 6, Moscow, Russia. Email: vasenyov@mail.ru Funding information DAAD‐Mikhail Lomonosov fellowship; Ministry Education and Science of the Russian Federation, Grant/Award Number: Agreement No 02.A03.21.0008; Russian Foundation for Basic Research, Grant/Award Number: 15‐34‐ 70003; Russian Science Foundation, Grant/ Award Number: 17‐77‐20046

Soil organic carbon stock in different urban land uses: high stock evidence in urban parks

Abstract: Urban areas are major producers of atmospheric CO2 emissions, but at the same time they can offset some of the associated C losses by retaining stable organic carbon in their soils (SOC). Despite the importance of urban SOC there are still many uncertainties associated, resulting in low accuracy of SOC stock estimations or in its neglection in the regional and national carbon budgets. We focused on one of the most extended urban areas of Italy (Milan) estimating SOC stock in the topsoil and comparing it for different urban land uses (park/non-park) and covers (woodland/grassland). We also compared urban SOC stocks with other typologies of natural and semi-natural land use in the region. We found generally high variability in urban soil properties. Average SOC of urban parks was higher (7.9 ± 2.4 kg m−2) than urban non-parks (5.3 ± 2.5 kg m−2); while SOC stock did not significantly differ for urban land cover types. Urban parks had SOC stock values comparable with forest, pasture and grasslands of the same region and higher than SOC of croplands. At the same time, urban non-parks had the lower SOC stocks values found in the region. The results highlighted the significant contribution of urban SOC stock to carbon budget estimations and differences based on urban land use types. Furthermore, we described the main pedological characteristics of investigated urban soils and we identified the factors that contribute to limiting our capacity to model urban SOC stock that can be partially overcome by the addressed strategies.

Changes of soil organic carbon stocks and CO2 emissions at the early stages of urban turf grasses’ development

Abstract: Urbanization coincides with remarkable expansion of turf grasses and their increasing role in environmental processes and functions, including carbon (C) sequestration. Soil organic carbon (SOC) stocks in turf grass soils are substantial, however, an intensive soil respiration is also likely. Therefore C sequestration in turf grasses remains uncertain, especially at the early stages after development, when C uptake and CO2 emissions are unbalanced. We analyzed changes in SOC stocks and CO2 emissions at the experimental turf grasses in Moscow megapolis during the three years period after establishment. An influence of the three contrast depths of organic layers (5, 10 and 20 cm) on soil and biomass C and on the ornamental functions of turf grasses was studied. Total CO2 emission from the turf grasses during the observation period exceeded C uptake in grass and root biomass by two to three times. Therefore the turf grasses at the early stages of development are important source of biogenic C. Although the C losses were substantial, CO2 emission decreased and C uptake in biomass increased by the end of the observation period. The highest ratio of sequestered and emitted C was obtained for the thick turf grass soil constructions with a 20 cm organic layer. The highest ornamental value, indicated by the projective cover and sprout density, was also obtained for the thick turf grasses, which is essential to consider for developing the best management practices and sustainable turf grass soil constructions.

Urban Soil’s Functions: Monitoring, Assessment, and Management

Abstract: Urbanization is a key trend of current land-use change, responsible for large environmental changes worldwide. Sustainable functioning of urban ecosystems is a priority goal of today and nearest future. Urban soil is a key component of urban ecosystems. Urban soils are formed and exist under predominant direct and indirect effect of anthropogenic factor. Urbanization was traditionally related to negative impacts on soils, whereas the capacity of urban soils to perform environmental functions is poorly understood. Traditional approaches to assess and standardize soil quality through static parameters and health thresholds give limited information on soil living phase and its dynamics. Quantifying urban soils’ functions directly relates soil quality to the role of soil for environment and society, that is especially relevant in urban ecosystems. This chapter aims to overview existing approaches to monitor and assess soil functions for a specific case of urban soils. Individual functions (i.e., gas exchange and carbon sequestration, bioresources, remediation, etc.) are observed over variety of bioclimatic conditions and for different levels of anthropogenic disturbance. Assessment results are further implemented to develop guidelines and best management practices to construct and treat urban soils for maintaining their functions and quality.