The article presents the results of investigations on the dynamics of the height, snow storage, and chemical composition of snow cover within the megapolis (Moscow) limits and conditionally background territories of the Solnechnogorskii raion (district) of Moscow oblast (Educational and Experimental Soil and Ecological Center “Chashnikovo” of Lomonosov Moscow State University) for the winter–spring period of 2023–2024. The research objects included the watershed adjacent area of the Klyazma River in the conditionally background conditions and two types of soil lysimeters from the Faculty of Soil Science of Moscow State University located within Moscow limits. The first type of lysimeters was characterized by various soil cultivation types at the continuous functioning in the conditions of mown meadow phytocenoses. The second type of lysimeters filled with repacked soil were installed under different land use types (bare fallow, long-term fallow land, overgrowing long-term fallow, and spruce, mixed, and broadleaved plantings) formed on a uniform mineral matrix represented by mantel loams. Snow cover dynamics was characterized by similar patterns both in the natural and urban conditions: maximum snow storage falls on February, followed by a reduction in spring. Minimum snow storage was established in lysimeter areas with spruce plantings, whereas maximum, for forestless sites, including grass long-term fallow and sites with lysimeters in the conditions of different soil cultivation. In the city conditions, significantly higher concentrations of certain alkali and alkaline earth elements (sodium, calcium, and strontium), as well as zinc and copper, were recorded. The concentrations of highly mobile anions, particularly chlorides, in melt water of the megapolis surpassed those in natural conditions 2–3-fold. This is consistent with the higher pH and electrical conductivity values for melt water in the megapolis conditions. Type of phytocenosis had a key effect on spatial distribution of snow and its components. Coniferous and mixed plantings retained more snow, which reduced the migration of lysimetric waters, whereas broadleaved and open areas experienced more intensive snow input and vertical migration of lysimetric water.

The composition of hydrocarbons in the upper horizons of replantozems in the traffic zones of the Eastern Administrative Okrug of Moscow was studied. Based on the proposed analytical approach, the contents of high-temperature boiling hydrocarbons (technogenic hydrocarbons), biogenic hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs) were determined in the soil samples. The content of biogenic hydrocarbons was associated with the amount of organic matter in the soils, and proportion of biogenic fraction increased when moving away from the source of transport pollution and reached 45

The distribution patterns of microelements in soils along two soil-geochemical catenas within the Chashnikovo Training and Experimental Soil Ecology Center (TESEC) of Moscow State University in Moscow oblast have been studied. The first catena, Klyaz’ma, is allocated to the northeastern slope of the Klyaz’ma River valley and includes eluvial, transit, transit–accumulative, and superaquatic landscapes. A carbonate double-sided biogeochemical barrier was diagnosed on this catena at the contact zone between the transit and the transit–accumulative landscapes. A distinctive feature of this catena consists in the modern functioning of the superaquatic landscape at its posthydromorphic stage of development. This catena is of the heterolithic type, because there is a transition from mantle loams on moraine to alluvial deposits within its boundaries. The second catena, Kirpichnoe Pole, consists of eluvial and a series of transit–accumulative landscapes of various hydromorphism rates. The eluvial landscape is located on the well-drained upper part of the northeastern slope. The second site within the transit–accumulative landscape is situated in the contact zone of the partially drained lower part of the slope influenced by the Krasnyi Voin gully. The third and fourth sites of this landscape are characterized by increasing hydromorphism. Soils throughout the entire length of the catena are formed on mantle loams underlain by moraine, which enables us to assign it to the monolithic type. The relevance of this study is determined by the fact that the typological differences between the catenas and the presence of a carbonate biogeochemical barrier in one of them enable us to determine similarities and differences in the behavior of elements under different conditions. It reflects general features common to soils within southern taiga landscapes of Moscow oblast. The distribution pattern of elements in soils is explained by soil-forming processes, past agricultural activities, bioaccumulation processes, and the influx of pollutants due to the proximity of these landscapes to the M-10 highway (Moscow–St. Petersburg) and to residential buildings. There is a correlation between the content of silt fraction and of elements V, Cr, Fe, Ni, Cu, and As in texture-differentiated soils and between medium silt fraction and Mn, Fe, As, Mo, Cd, and Hg in alluvial soils. The increase in hydromorphism on the studied catenas results in the accumulation of iron-manganese concretions in soils. The carbonate barrier reduces the overall migration flow, primarily of elements of the iron family.

The main types of soils in the northeastern part of the Sakhalin island have been studied under oil pollution conditions (1 and 10 years) vs. their background counterparts. Patterns of hydrocarbon transformation have been revealed in oil-contaminated soils; the possibility of launching self-purification processes is shown based on the results of assessment of the composition of petroleum hydrocarbons (TPHs). Analysis of n-alkanes as markers of TPH biodegradation has shown a change in their content and composition, depending on the degree and age of soil contamination with TPHs, as well as the sorption capacity of soils. Mechanisms of soil self-purification are triggered during the first year, which leads to a change in the composition of n-alkanes: light fractions volatilized and C16–C23 alkanes undergo biodegradation. Under conditions of 1-year oil contamination of soils, the composition of petroleum hydrocarbons undergoes significant changes, which are expressed in an increased proportion of microbial n-alkanes (ΣC20–25). An increase in the content of high molecular homologs ΣC26–C34 has been found compared to the initial state of oil-contaminated soils and the oil composition. The calculations of CPI (coefficient of oddness), Ki (coefficient of biodegradation), and Kw (“degree of waxiness”) demonstrated the transformation of the composition of n-alkanes and general transformation of petroleum hydrocarbons in time. The use of the sum of odd n-alkanes C27, C29, and C31 as a diagnostic indicator is a solid base for selecting background soils in the zone of hydrocarbon deposits.

Understanding the mechanisms underlying the accumulation and stabilization of organic carbon in soils is necessary to preserve and enhance their sequestration potential and to implement sustainable land use practices when converting soils to agricultural use. The aim of this work was to study the role of laccase in binding of phenolic acids to mineral phases and the role of laccase in organic carbon stabilization at low substrate concentrations occurring in soil solutions. The laccase of the white rot wood fungus Cerrena unicolor (VKM F-3196) was used as biotic catalyst. Laccase was immobilized on illite and on kaolinite modified with aluminum hydroxide – kaolinite-Al(OH)x. One of the common natural manganese (IV) oxides, pyrolusite (b- MnO2), was taken as a powerful abiotic catalyst for comparison. The oxidative activity with 1 mM ABTS (diammonium salt of 2,2'-azino-bis-(3- ethylbenzthiozoline-6-sulfonic acid) as a substrate at pH 4.5 was 124 U/g for pyrolusite, 0.25 U/g for illite and was absent in modified kaolinite. The activities of laccase immobilized on modified kaolinite and illite were 1.17 and 0.82 U/g, respectively. An equimolar mixture of gallic, protocatechuic, p-hydroxybenzoic, syringic, vanillic and ferulic acids (0.01 mM each in 0.01 M KNO3, pH 4.7) was incubated with minerals for 1, 24 and 72 hours. Phenolic acids loss was determined by reversed-phase high pressure liquid chromatography and carbon loss was determined on a TOC-L analyzer. The highest reactivity in interaction with all minerals was found for gallic acid (40–100% loss in 24 hours) and to a lesser extent for protocatechuic acid (19– 100% loss in 24 hours). Significant loss of p-hydroxybenzoic acid was observed only in the presence of illite and complex of illite with laccase, vanillic acid reacted only with pyrolusite (50% loss in 24 hours). The loss of syringic and ferulic acids (80–100% in 24 hours) was observed only in the presence of pyrolusite and complex of laccase with modified kaolinite. Despite 2 orders of magnitude lower oxidative activity and 3 times smaller surface area (18 m2/g versus 54 m2/g in b-MnO2) the complex kaolinite- Al(OH)x-laccase adsorbed an amount of Corg comparable to pyrolusite (6.5 g/kg). The amount of carbon bound to complex of illite-laccase was 3 times lower (1.7 g/kg) despite the highest surface area of illite (100 m2/g) and catalytic activity, similar to kaolinite-Al(OH)x-laccase. Laccase enhanced carbon binding by modified kaolinite and illite by 2–3 times. Our results show the important role of laccase and metal hydroxides in Corg stabilization. Preservation and enhancement of the natural level of laccase activity in soils by regulating pH and humidity, as well as the introduction of laccase preparations in immobilized form into soils may be a promising approach to increase organic carbon stabilization potential of soils of agricultural use and requires further research in this area.

In this paper, we discuss questions of the common origin of the disciplines of soil science and landscape geochemistry. Their closeness lies in their common objects of study - soils and landscapes - and a common methodological approach based on systemic analysis, the evolutionary-historical principle, and the priority of the scientific approach in solving practical problems, as laid down by V.V. Dokuchaev. The prominent naturalists A.E. Fersman and V.I. Vernadsky emphasized the genetic connection and mutual enrichment of these sciences through theoretical concepts and experimental data. When considering common problems of these two disciplines, particular importance is given to the biological cycle as a fundamental law governing the functioning of ecosystems. In the classification of soils and soil-geochemical catenae, their position within the system of geographic landscapes is especially significant. Currently, priority issues include anthropogenic impacts and environmental monitoring, which involve studies of element migration over the biosphere, as well as efforts towards mathematical modeling.

An Erratum to this paper has been published: https://doi.org/10.1134/S1064229325020024

In the work the influence of biota and irradiation on the stability of iron colloids in mire waters is studied. The dynamics of the processes of photo- and biotransformation of colloidal iron has been studied. It is shown that the mechanisms of these changes are different: during insolation, the decrease in the iron content in the colloidal fraction occurs due to the formation of larger poorly soluble hydroxide particles (>0.22 μm), and in the presence of biota, a part of iron passes into a fraction of a smaller size (<1.4 nm).

For landscape conditions in the upper reaches of the river Klyazma, Solnechnogorsk district, Moscow region, the height and reserves of snow cover were investigated, and the chemical composition of the snow was determined. The basis for considering the component composition of snow cover was the geochemical taxonomy of chemical elements based on the characteristics of water migration and abundance. Data from 23 snow sampling points were interpolated in SAGA GIS using the inverse distance weighting (IDW) method. On this basis, zones differing in the chemical composition of snow are identified. One of the zones is confined to the M-10 Moscow-St. Petersburg highway, while the second borders on populated areas. The area close to the highway is characterized by increased levels of calcium, sodium, aluminum, and chloride ions in the snow cover. The second zone, bordering populated areas, is characterized by a high content of calcium, copper, and manganese in the snow. For the third zone, low concentrations of components in the snow were observed which are characteristic of a superaquatic landscape due to the distance from sources of pollution. The studied composition of snow waters belongs to the bicarbonate-sodium-calcium-chloride class. It has been shown that the height and reserves of snow cover are partially controlled by two factors: the type of elementary landscape and the type of ecosystem. Against this background, the spatial distribution of concentrations of elements and anions in snow is predominantly controlled by the anthropogenic factor.

A comparative analysis of the composition of lysimetric waters for 2021–2022 was carried out for two groups of stationary soil lysimeters under urban conditions. The first group of lysimeters is formed by the “fallow–herbaceous phytocenosis–overgrown fallow–spruce forest–mixed and broad-leaved plantation” system developing on the same type of mantle loam. The second group of lysimeters represents soils with different types of tillage: conventional plowing, extradeep plowing according to Bushinsky, plowing according to Mosolov, and deep plowing according to Kachinsky. The same type of migration of components, in which the most migrating elements include carbon, mono- and divalent cations, and chloride ions with minimal migration of iron, manganese, and aluminum, is shown for both groups. The concentration of such important biophilic elements as magnesium, calcium, potassium, and carbon and, among anions, chloride and sulfate ions increases significantly in the group of lysimeters under various types of vegetation as the tree canopy develops and, increasing, accordingly, the intensity of the biological cycle increases in migrating waters. Cluster analysis identifies two different subgroups in terms of the composition of natural waters: the first one is formed by the “fallow–herbaceous phytocenosis–overgrown fallow” system, and the second contains tree plantations. A cluster that characterizes the composition of water in lysimeters with reclamation plowing according to Mosolov and deep plowing according to Kachinsky is distinguished in the group of lysimeters with different tillage. At the same time, individual aggregates form lysimeters with conventional plowing and ultradeep plowing according to Bushinsky. This is explained by the fact that the initially created soil-profile design, which is characterized by the placement of eluvial and illuvial soil horizons in various combinations and at different depths, is transformed in this group of lysimeters.

The long-term component composition of natural waters in the snow waters–soil solutions–soil–ground waters–surface waters system has been studied within the landscapes of the upper reaches of the Klyazma River . It has been determined that the regular excess of the content of the main macro- and microelements in soil solutions in comparison with snow waters is first replaced at subsequent stages by an increase in the concentration of components in soil–ground water, followed by a decrease in the content in surface waters — streams and river waters. It is shown that the relatively high mobility of sodium, magnesium, potassium, and calcium, and anions such as chloride and nitrate ions, is accompanied by a significant decrease in the mobility of elements of the family of iron, copper, and zinc at the transition from groundwater to surface water. This explains the wide distribution of segregated forms, which are presented by nodules in soils of semihydromorphic landscapes, up to ortsands, and the formation of typical bog ores in the boggy conditions of near-terrace depressions on the border with the superaquatic landscape. Thus, the composition of natural waters and its change serves not only as a good, but also a necessary tool for explaining the features of migration of elements in the soil — natural water system and explaining the mechanism of how soil formations arise.

The change in the distribution of Cu compounds by size fractions with an increase in its concentration in noncontaminated surface waters has been studied experimentally. It has been shown that dissolved organic substances in natural waters, especially humic substances, have a significant influence on the forms of Cu occurrence at a high content (up to 50 mg/L), determining the stability of its colloidal compounds. In surface waters with a low content of organic matter that are contaminated with copper, high-molecular Cu compounds will be formed, which can lead to the removal of Cu into the bottom sediments.

— Humic substances (HS) are heterogeneous and polydisperse compounds formed in soils, sediments and waters during the decay and transformation of organic residues (the process called humification). The role of extracellular free-radical condensation reactions (secondary synthesis) in the formation of HS is a subject of debate. Here we have studied the formation of HS from a mixture of monomers under the dynamic conditions and at low substrate concentrations in the presence of laccase from the fungus Coprinus comatus F-2940. Laccase was immobilized on kaolinite modified with aluminum hydroxide. We have investigated some properties of the enzyme, reactivity of phenolic acids and amino acids in the presence of laccase. The optimum of 2.6-dimethoxyphenol (2.6-DMP) oxidation by free laccase was at pH 6.0. Upon immobilization, it shifted to the acidic region (pH 4.4), the thermal stability decreased, however the kinetic parameters of 2.6-DMP oxidation remained unchanged. In terms of reactivity (% of substrate conversion by free laccase) the individual phenolic acids formed a series: caffeic (72) > ferulic (53) > gallic = syringic (43) > protocatechuic (5.5) > vanillic = p-hydroxybenzoic (0). In the mixture of phenolic acids, gallic acid was most efficiently oxidized (50%), while the other acids were oxidized in comparable amounts (13–17%). The conversion of phenolic acids increased in the presence of lysine. When a mixture of gallic, protocatechuic, syringic, ferulic acids (0.01 mM each) and lysine (0.02 mM) was passed through a flow-through microcolumn, immobilized laccase effectively oxidized the phenolic acids, the reaction products bound to the mineral phase, staining it dark. According to high performance liquid chromatography, the molecular weights of compounds extracted from the mineral phase did not exceed 900 Da, thus fulvic acid-like substances were formed. Results of the study suggest an important role of free-radical heterophase reactions in the formation of the molecular composition of the liquid phase and organo-mineral complexes.

The effects of dissolved organic matter (DOM) fractions of various sizes and Cd2+ on the growth rate of Scenedesmus obliquus has been studied. The studies were carried out both separately for DOM and Cd2+, and for both. DOM fractions (>30, 10–30, 3–10, 1–3 and <1 kDa) has been obtained by ultrafiltration; algae growth was assessed by the chlorophyll content, determined spectrophotometrically at 678 nm. It has been found that cadmium at concentrations of 5.62–22.5 μg/L stimulated and at concentrations of 56.2 and 112.4 μg/L suppressed the growth of algae. DOM fractions had different effects on S. obliquus, they both reduced and stimulated the growth of algae in the range of 0.001–1 mg C/L, and the effect on the growth rate was in the range of ±10–25%. The greatest positive response of microalgae was shown by the fraction <1 kDa, which was probably associated with the active participation of this fraction in the algae nutrition. In the presence of inhibitory concentrations of Cd2+, DOM fractions of 30, 1–3, and <1 kDa had a positive effect on the growth of S. obliquus. The probable mechanisms of such effect of DOM was its binding of Cd2+ ions (mainly on the surface of algal cells), as well as the high biological activity of its low molecular weight fraction <1 kDa. For the first time, data were obtained on the effect of heavy metals on the growth of algae in the presence of DOM fractions of different sizes. The data obtained expand our understanding of the mechanisms of regulation the number and state of microalgae in ecosystems, when affected by heavy metals.

The types and total reserves of mortmass in the forest litter of the main types of biogeocenoses within the stationary bulk lysimeters of the Soil Experimental Station of Moscow State University have been studied. It is shown that the litters are mainly destructive in spruce forests, fermentative in mixed stands, and humified in broad-leaved forests. There is an exchange of plant debris between biogeocenoses: leaves are found in spruce biogeocenoses, overgrown fallows, and black fallow. The calculated litter-debris coefficient (LDC) according to N.I. Bazilevich enables us to characterize the biological cycle in spruce plantations as the slowed-down type: the LDC is 2.8, which is related to the domination of decomposition-resistant needle debris. In broad-leaved and mixed plantations, the turnover is intense: the LDC is 1.2. It is shown that the content of mineral admixtures should be taken into account when calculating the total organic matter reserve in litter; and their portion should be estimated during laboratory studies.

This paper describes properties of soils and litter formed in pine forests of Moscow oblast in areas used by gray herons as nesting grounds. It is established that the total trophicity of ecosystems sharply increases in areas with a high density of heron nesting sites compared to control sites, which is manifested in the widespread occurrence of species with strict requirements as regards the soil nutritive regime. The elevated content of water-soluble phosphorus forms, nitrates, sulfates, potassium, magnesium, and calcium in soils of heronries confirms this. By contrast, the concentrations of main components in control soils are typical for the zone of coniferous–deciduous forests. Taking the low mobility of phosphorus and its probable fixation in the composition of immobile complexes, it has been suggested that elevated concentrations of this element in areas where sod–podzolic soils are widespread and the role of anthropogenesis is excluded, which may indicate past effects of ornithogenic ecosystems.

The operation of stationary soil lysimeters is largely determined by the areal and vertical limitations of the soil mass. The areal spatial limitations of large lysimeters operating at the Moscow State University Soil Station and the proximity of phytocoenoses developing in them to each other contribute to the additional transport of plant litterfall by wind, while the vertical limitations eliminate the role of groundwaters and their soil-forming effects. The absence of lateral subsurface flow that is typical for natural landscapes and the increased inflow of alkaline-earth elements with atmospheric precipitation and dust reduce the manifestation of the eluvial–illuvial process. Comparative analysis of lysimetric waters in 1967–1968 and in 2014–2015 shows a significant increase in concentrations of such cations as calcium, sodium, magnesium, and potassium and such anions as chloride and sulfate over this period. The local spatial geochemical contrast of lysimetric waters caused by the impact of deicing agents does not affect the relative migration capacity of elements. Based on their biogeochemical accumulation levels in the soil, macroelements form the following series Ca > K > Al > Mg > N; microelements: Zn > Sr > Cu > Ba. The above patterns persist in all types of lysimeters. The calcium concentration in soils increases in the series: broadleaf forest > mixed forest > spruce forest > black fallow. The increased accumulation of elements in soils of spruce forests correlates with the humus type (moder-like) formed under them; this humus type is determined by the combination of coniferous and deciduous litterfall.

The composition of water-soluble macro- and microelements and anions has been studied in soils formed within a monolithic soil–geochemical catena. It has been shown that the carbon and nitrogen contents regularly increase from eluvial to accumulative landscapes parallel to their hydromorphism. The distribution of water-soluble forms of macro- and microelements is related to bioaccumulative processes and features of eluvial–illuvial differentiation of soils. The margins of the watershed depression are characterized by the combination of eluvial–illuvial differentiation and intensive lateral removal of elements in spring, which determines the maximal leaching of the top soil horizons. The data of the cluster analysis confirm that there is a correlation of soil genesis and location in the system of geochemical catena with the composition of water extracts.