Articles

Analysis of tilosin migration in sand and sod-podzolic soil: a laboratory filtration experiment A. K. Toskhoporan, A. P. Kiryushina, S. V. Patsaeva, A. Yu. Shulakov, A. D. Batakov, V. A. Terekhova, A. B. Umarova The migration of the antibiotic tylosin in fine-grained quartz sand and the upper layer of sodpodzolic soil was studied in laboratory filtration experiments to obtain output curves and calculate the parameters of antibiotic migration in variants with different pore structure. It was found that the transfer of tylosin can be tracked by analyzing its concentration in filtrate portions, measured by the absorption spectra of the antibiotic. It has been experimentally shown that the appearance of an antibiotic occurs in the first shift of the entire pore space of the column. Tylosin actively migrates in all variants of sod-podzolic soil, and its erosion front reaches 40 cm. Similar behavior of antibiotics and potassium cations in soil was revealed. A high negative correlation (k = 79% according to Pearson) was found between the direct method of determining the tylosin content in filtrates by spectrophotometry and its algotoxicity in migration experiments. Keywords:soil, porosity, granulometric composition, output curves, macrolide antibiotic, mixing step, migration, spectrophotometry, ecotoxicity.

This work aimed to study the effect of sorbents on the phytotoxicity of soils of heaps by changing the values of germination energy and seed viability, as well as morphometric indicators of model plants.Three dumps were selected as the objects of research – two rock dumps (Kalinin mine, Zaperevalnaya mine and one dump of a central processing plant (Chumakovskaya CPP), located on the territory of the Donetsk coal basin within the city of Donetsk, Donetsk People's Republic. Soil of heaps was used for laboratory modeling, as well as soil with the addition of biochar (1%) and layered MgFe-LDH double hydroxide (0.5%). Festuca rubra L. and Trifolium rubens L. were used as test cultures. It was found that the phytotoxicity of technogenic ecotopes had an inhibitory effect on the seed viability and germination energy of the seeds of both test crops. The greatest phytotoxic effect was found for embryozems of the Chumakovskaya CPP, where the decrease in seed viability and germination energy was 83–92% relative to the control. The most sensitive indicators were the length and mass of the root. The submission of sorbents, especially MgFe-LDH, contributed to a decrease in phytotoxicity, most pronounced on the embryozemsof the Chumakovskaya CPP, which was confirmed by the positive dynamics of morphometric parameters. According to the integral toxicity index, the rock of the dump of the Chumakovskaya CPP is assigned to hazard class I (extremely high toxicity), while the dumps of coal mines are classified as low toxicity or normal. The greatest positive effect was fixed with the use of MgFe-LDH, which not only stimulated growth processes, but also contributed to the transition of the substrate to the category of a lower hazard class.

This study assessed the impact of soil surface contamination with used motor oil on the migration and accumulation properties of zinc and copper, as well as estimated the activities of soil urease and catalase, two of the most important parameters characterizing soil self-healing processes under oil contamination. X-ray fluorescence, titrimetric, infrared spectrometry, and other methods were used to determine soil parameters and analyze petroleum products. Six years of monitoring under field experimental conditions revealed a significant accumulation of zinc in the surface soil layer (0–10 cm)—up to three times that of the control. This accumulation was due to the increased influence of the natural geochemical barrier—the upper organogenic soil horizon—by the added petroleum products, as well as the increased activity of ureolytic bacteria capable of precipitating this metal as insoluble carbonate minerals. Copper exhibits significant mobility under contaminated conditions, characterized by migration from the 0–10 cm layer and accumulation at a depth of 10–30 cm, exceeding the control level by up to 2.6 times, due to the high affinity of this metal for water-soluble fractions of petroleum hydrocarbons, heavy precipitation that fell during the monitoring period, and the presence of a thick clay layer at a depth of 60 cm and below, which served as a geochemical barrier preventing its further downward migration. Urease activity in the soil increased significantly, which was observed throughout the experiment. Soil catalase activity was inhibited immediately after the application of the petroleum product to the soil, and by the end of the study period, it increased to values 47,6% higher than the control level, indicating a gradual restoration of the microbiota and stimulation of soil self-purification processes.

Thermal diffusivity of typical chernozems from Kursk region collected under a four-year-old fallow land, a fifteen-year-old fallow land, and a 46-year-old shelterbelt was studied. Undisturbed soil samples were cut vertically using thin-walled metal cylinders 7 cm high and 5 cm in diameter. Three replicates were collected for each depth. Thermal diffusivity was measured using a laboratory steady-state method, pre-saturating the samples with capillary feeding on a sand substrate and then drying the samples step by step to an air-dry state. The range of soil moisture content in the studied samples during laboratory measurements was from 0,03 cm3•cm–3 to 0,55 cm³cm–3. The bulk density of the samples varied from 0,85 g•cm–3 to 1,42 gcm–3, the organic carbon content changed from 2,1 to 3,9%. Thermal diffusivity of the studied horizons varied within the range of 1,35–4,03•10–7 m2s–1 under a four–year–old fallow, 1,06–4,28•10–7 m2s–1under a fifteen–year–old fallow, and 0,93–2,89•10–7 m2s–1under the shelterbelt. The correlation coefficient between the maximum value of thermal diffusivity and the sample bulk density was 0,61, and between the maximum value of thermal diffusivity and the organic carbon content it was –0.59. The dependences of thermal diffusivity vs. moisture content in most cases had the form of a curve with a slightly pronounced maximum in the range of high moisture contents and a section of almost unchanging thermal diffusivity in the range of moisture contentslower than 0,10 cm³•cm-3. Samples from the upper part of the former arable horizon under a fifteen-year-old fallow stood out in relation to the others; for these samples, the dependences of thermal diffusivity vs. moisture content had a pronounced S-shaped form, with an unusually long flat section in the moisture content range from 0,03 to 0,20 cm3 cm–3 and a sharp increase of thermal diffusivity in the moisture content range of 0,20–0,30 cm3 cm–3. A comparison of the results with previously obtained data for virgin land and arable land showed that in the series “virgin land – arable land – four-year-old fallow” the thermal diffusivity of the topsoil increases, while in the series “four-year-old fallow – fifteen-year-old fallow –shelterbelt” it decreases. Fifteen years of fallowing is not enough to return the soil thermal diffusivity to virgin land values.

The lithological matrix of surface soil profiles in the northern Mologo-Sheksna Lowland, within the wide valley of the lower Sheksna River and the foothills of the Andoga Ridge, reveals the final stage of Late Pleistocene aeolian sedimentation, reflected in the composition of the surface soils. Morphological and genetic analysis of soil profiles at the macro- and microlevels, supported by analytical characteristics and particle size distribution data, allowed us to identify and substantiate at the regional level a series of four contiguous layers of different ages and lithologically contrasting features. The base of the studied soil profiles is the Moscow glacial basal till (layer I, which displays consistent features of Mikulino pedogenesis (Bt horizons). The final stage of loess sedimentation in the upper part of the soil profiles during the Late Glacial (layer III) has been dated using the OSL method and falls within the range of 17,000–22,000 years ago. Layer II, represented by gravelly-sandy sediments in the middle part of the profiles of several of the studied soils, reflects a local stage of active sedimentation after the Mikulino period, during which the upper part of the glacial till may have been truncated (eroded). Thus, the studied soils represent a pedocomplex formed in the Late Pleistocene (a 150,000-year macrocycle). Identifying the final stage of loess sedimentation in the Late Glacial will allow us to assess the contribution of soil and lithological processes to the formation of the profile of loamy soddy-podzolic soils. Establishing the final stage of eolian sedimentation in the Late Glacial is also of great importance for paleogeography, as it reflects the impact of the global climatic rhythm at the Late Pleistocene-Holocene boundary on the modern landscape. The mantling of the Sheksna River valley by glacial basal till confirms V.V. Dokuchaev's (1877) concept of the role of glaciations in the structure of river valleys on the Russian Plain. The terrace levels in the studied areas represent ancient basement steps and do not belong to the modern river valley.

The article presents the results of an 18-month field experiment assessing the impact of 11 mulching substrates used in urban soils on a range of physical, chemical, and biological properties. The following substrates were studied: serpentine, marble, volcanic tuff, foam glass, coconut chips, painted and unpainted pine chips, large and small fractions of larch bark, and large and small fractions of pine bark. The substrates used were shown to have no negative impact on pH, total carbon (Corg) content, or its water-soluble forms (Cws), and no effect of the substrates on soil bulk density. The use of mulching substrates on urban soils contributed to an increase in the biological activity of the soil prokaryotic complex and a decrease in the number of sanitary-indicator and potentially pathogenic bacteria (Escherichia coli) in the soil, which reduces potential risks to the health of the urban population. The most favorable soil properties, based on the totality of the studied parameters, are formed under organic mulching substrates consisting of fine-sized particles, coconut chips and larch bark. An increase in the content of microscopic fungi in the upper horizon of urban soil under a 5-cm-thick mulch layer was detected. This may pose potential risks to human health due to the allergenic and potentially pathogenic properties of some soil micromycetes and requires further research. The obtained results allow us to recommend mulching urban soils with organic substrates not only for decorative purposes but also to enhance biological activity and, consequently, improve the biological condition of soils in anthropogenically transformed conditions.

Despite the significant role of the black garden ant (Lasius niger) in soil formation processes, the seasonal dynamics of microbial biomass in its nests and adjacent urban soils remains poorly understood. The relevance of this study is related to the need to assess the contribution of L. niger to the biological activity of soils under anthropogenic stress. The study is aimed at analyzing the dynamics of microbial biomass and its activity in the nests of L. niger ants and the surrounding urban soils during the growing season. In this work, methods of luminescent microscopy were used to estimate the total number of microorganisms and the dynamics of its changes during the growing season, as well as the method of multisubstrate testing to determine the functional diversity of microbial communities and methods of mathematical statistics. In the studied urban soils, there was a significant decrease in the proportion of fungal and an increase in the proportion of bacterial components in microbial biomass compared to zonal soils. The predominance of fungal cells (spores and yeast cells) was recorded in the fungal biomass, while their maximum number and minimum biomass of fungal mycelium were noted at the end of the growing season. The effect of L. niger ants on the composition of microbial biomass in the soil was manifested in an increase in the length of the fungal mycelium and bacterial biomass reserves compared with the control. The influence of anthropogenic stress on the structure of microbial biomass in anthills is more pronounced than in control soils. The nesting activity of ants had a significant impact on the functional parameters of microbial communities formed in the soil. The material of the anthills showed a change in the spectrum of organic substrates consumed by the microbial complex and the rate of their consumption compared to the control soils. It was found that microbial communities less climactic than in the soil form in anthills in areas with the lowest anthropogenic load, which may be due to a more intense foraging activity of insects in these areas. It should be noted that the stability index (d) of microbial complexes in anthills showed less variability during the growing season than in the same indicator in soils.

Yu. V. Zakalyukina, A. R. Zaytsev, A. A. Belov, Yu. A. Zavgorodnyaya, M. V. Golichenkov The study assessed the impact of the nest-building activity of Camponotusvagus ants on the biological activity of microbial communities in the nest material compared to the surrounding soil. The objects of the study were samples from the aboveground and underground parts of theblack carpenter’s nest, built in a dead wood of Pinus sylvestris L., collected in the Ryazan region in a pine forest on humic arenosols. Using optical and scanning electron microscopy, a specific "nest material" was characterized, consisting of wood, plant debris and sand, densely woven with fungal mycelium, in which the presence of actinomycetes and unicellular bacteria forming associations was also shown. Comparative analysis of the elemental composition (C, N, P, S) demonstrated that this woody material is significantly enriched in all biophilic nutrients, and the C:N ratio in the nest material is effectively reduced compared to dead pine wood. The microbial community of the "nest material" was characterized by an increased intensity of processes involved in the nitrogen and carbon cycles (potential activity of nitrogen fixation, denitrification, CO₂ emission, and CH₄ production) compared to the microbial communities of the soil part of the nest and the control soil. Thus, during their nest-building activity in pine forests formed on poor sandy soils, Camponotusvagus ants intensify wood decomposition and thereby create unique habitats ("hotspots") with elevated biological activity. This underscores the important ecosystem function of carpenter ants. There are grounds to suggest possible symbiotic relationships between the ants and the mycelial microorganisms that form the so-called "nest material".

We obtained data on the number of saprotrophic bacteria and the structure of bacterial complexes of cultivated bacteria of the soil of the fallow field, the material of anthills located in the field under study, and ants of the species Lasius niger and Lasius flavus, which are dominant species in this fallow field. It has been established that ants of two closely related species from the genus Lasius differ significantly in the number and composition of the cultivated bacteria associated with them, and have a different effect on the microbiocenosis of the soils they inhabit. A high similarity of bacterial complexes of L.niger ants and the material of their nests was shown, at the same time, such a pattern was not revealed for L. flavus. It has been established that the structural components of anthills differ in the number and composition of cultivated bacteria. It has been shown that in general, anthills are loci of increased abundance and higher bacterial diversity compared to control soils, which can be traced not only in the surface soil layer. It has been found that the nesting activity of ants promotes the redistribution of microorganisms down the profile, as a result of which the increased biodiversity of microorganisms is maintained at a greater depth than in the control. To a greater extent, this phenomenon is characteristic of soil-dwelling ants L. flavus. In anthills, an increased number of fertility-improving bacteria with high biotechnological potential, such as Pseudomonas koreensis, capable of fixing atmospheric nitrogen, and Paenibacilluschitinolyticus, showing chitinolytic activity, was found compared to control. According to the results of additional studies, representatives of Agrobacterium radiobacter, not identified by direct inoculation, were identified from the accumulation culture on Ashby's nutrient medium. With the help of genome-wide sequencing, several species of bacteria were identified that were not determined by mass spectrometry.

Theresults of studyingmicroarthropodcomplexesinsoilsunderdeciduouswoodyvegetation of fourrecreationalareas of Moscowwithin the CentralandWesternadministrativedistricts: the garden of the manorMuseum of L.N. TolstoyinKhamovniki, the BotanicalGarden of Moscow State UniversityonVorobyovyGory, the VorobyovyGoryNatureReserve, the TroparevskyLandscape Reserve are presented.Soil and zoologicalwork was carried out in2018,2019and2024. Dark humus stratozem, gray humus surface residual carbonate, gray humus (turf) and other soils were studied among the soils.
17taxa of smallarthropods were found,from10to14in the soils of most of the studiedsites.Ticks(Acari)predominatedeverywhere,accounting for at least53%of the totalnumber of microarthropods. The share of Collembolavariedfrom21%to45%. The number of microarthropodssometimesreachedvaluesup to 118,000specimensm‒2,whichisseveraltimes higher than the knowndatafornaturaldeciduousforests near Moscow.Aplot has been allocated in the centralpart of Moscowwith a lowpopulationonaveragenomore than 20,000specimensm‒2,where the destruction of leaflitter,frequentmechanicaldisturbance of the surfacehorizons of the soilandothertypes of impacts have ledto a steadydecrease in the numberandcomposition of microarthropodcomplexes.Thelowestvalue of the soilbiologicalqualityindex(QBS=55) was recorded at thesamesite. The resultsobtainedconfirmthatindicatorssuchas the number(populationdensity),composition of microarthropods,andthesoilbiologicalqualityindex(QBS)can be usedasindicators for assessing the state of soils.