This work describes the microbial community structure of the continuously revegetated chronosequence of a former sand quarry, which demonstrates a unique example of nearly complete soil restoration in less than 100 years. Samples were collected at five time points (0, 3, 30, 70 years and mature soil) from the entire set of soil horizons, revealing the history of pedogenesis. Real-time PCR was applied to quantitatively describe the bacterial and archaeal communities. High-throughput sequencing of the bacterial and archaeal V4 variable region of the 16S rRNA gene was used to identify abundant microbial taxa. A beta-diversity analysis revealed that the prokaryotic community structure responded strongly to the processes of organic matter accumulation and the corresponding evolution of the soil into discrete horizons. Changes in soil microbiota in the course of soil profile evolution revealed three groups of prokaryotes, which tended to accumulate in the specific soil horizons and might be associated with the certain soil-forming processes, including plant roots growth. This research showed the heuristic potential of soil horizon profiling in microbiological studies as opposed to the formal depth-dependent separation of the soil layers. The results allowed us to trace the relationship between the structure of the soil prokaryotic community and the peculiarities of the evolution of the podzolic soil profile as well as to identify the microbial indicators and drivers of primary pedogenesis.

For the targeted selection of microbial communities that provide cellulose degradation, soil samples containing cellulolytic microorganisms and specific plant residues as a substrate can be used. The details of this process have not been studied: in particular, whether the use of different soils determines the varying efficiency of communities; whether these established cellulolytic communities will have substrate specificity, and other factors. To answer these questions, four soil microbial communities with different cellulolytic activity (Podzol and the soil of Chernevaya taiga) and substrates (oat straw and hemp shives) with different levels of cellulose availability were used, followed by trained communities that were tested on botrooth substrates (in all possible combinations). Based on the analysis of the taxonomic structure of all communities and their efficiency across all substrates (decomposition level, carbon, and nitrogen content), it was shown that the most important taxa of all trained microbial cellulolytic communities are recruited from secondary soil taxa. The original soil does not affect the efficiency of cellulose decomposition: both soils produce equally active communities. Unexpectedly, the resulting communities trained on oats were more effective on hemp than the communities trained on hemp. In general, the usage of pre-trained microbial communities increases the efficiency of decomposition.

Studying the soils in the periodical flood zone of three reservoirs is of promising importance for their subsequent return to economic activities. Research on the bacterial and archaeal communities of soils that are periodically or continuously flooded by reservoirs is still insufficient. To evaluate the chemical status of soils and their microbiota, the study was conducted in the Yumaguzino, Nugush, and Slak reservoir sites in the South Ural area (Russian Federation). The bacterial and archaeal communities of periodically flooded and non-flooded soils were investigated after a comparative investigation of chemical, hydrological, and climatic factors. It was discovered that flooded soils had anoxic conditions during the whole of the year, with brief drying intervals of limited length and low levels of effective temperatures. In terms of chemistry, flooded soils are distinguished by increased acidity, a fall in organic matter, and an increase in alkali-hydrolysable nitrogen. Compared to their counterparts in non-flooded soils, bacterial and archaeal communities in flooded soils are significantly different. Generally speaking, the biodiversity of flooded soils rises with the duration and depth of floods. Significant variations at the phylum level are mostly caused by a decline in the relative presence of Thaumarchaeota and an increase in Proteobacteria and Chloroflexi representation. It was discovered that the Euryarchaeota phylum was either absent or had a significantly decreased relative prevalence at the sites of intermittently flooding soils.

This research evaluates the development of microbiomes in primary soils, forming in various mining dumps in the arid terrain in the Republic of Bashkortostan, Russia. A metagenomic analysis of the communities was performed by sequencing extended gene sequences. The evaluation of the agro-chemical properties was in accordance with conventional pedology methods. Inverse voltammetry was used to measure the heavy metals (lead, cadmium, mercury, zinc, copper, and nickel) and arsenic content. In all the samples studied, Actinobacteria and Proteobacteria phylas dominated, and, in smaller numbers, Acidobacteria and Bacteroidetes were present. In the natural samples, the proportion of Actinobacteria was higher, and the proportions of Proteobacteria and Bacteroidetes were lower than in the samples from anthropogenically disrupted soils. Verrucomicrobia bacteria and Thaumarchaeota archaea were not found in the forming soils of the Kulyurtau and Tubinsky quarries, although in all other samples, there was a significant content of representatives of these types. Soil formation was observed at the Kulyurtau and Tubinsky mines, with a self-restoration period of more than 30 years. The microbial communities of the forming soils were similar in species richness to the background soils, and the alpha diversity showed a high level of dispersion, although the beta diversity had a different clustering, but the absence of Verrucomicrobia and Thaumarchaeota phyla in the samples from both sites indicates the underdevelopment of new soils compared with the natural background. Agrochemical indicators showed a dependence on the type of growing vegetation and the degree of anthropogenic load, and the correlation with the microbial composition of soils was traced poorly.

Agro-development of northern territories results in radical transformation of soils of these ecosystems. On the example of Nadym district (N 65.5; E 72.6) of Yamal-Nenets Autonomous Okrug (Russia) it is shown that the process of agrogenic transformation of reference podzols is similar to the process of formation of Plaggen soils, which were repeatedly found in Northern Europe and other regions (Plaggen Anthrosols - result of Plaggen Management). As a result of the application of large amounts of organic substrate (Plaggen Material), the thickness of the surface horizons increases considerably (from 3 cm to more than 30 cm in some cases). These soils occupy an intermediate position from reference soils to highly transformed - Hortic/Plaggic Podzols. Hortic and Plaggic horizons are characterized by reduced acidity (pH H2O 5-6, pH CaCl2 4-5), increased content and stock of organic carbon (5.4-14.5 %). Soils of agrogenic and postagrogenic ecosystems are characterized by relatively high content of basic nutrients (P-P2O5 up to 386 mg kg- 1, K-K2O up to 239.0 mg kg- 1) and clay (up to 20.9 %), also the degree of their microstructure increases in comparison with reference Podzols of Nadym district. The taxonomic composition of soil microbiome also changes greatly in the process of agricultural development of soils. In reference Podzols Proteobacteria, Actinobacteria and Bacteroidetes dominate. In general the microbiological profile in the of agrogenic and postagrogenic soils shifts towards the increase of the phyla Proteobacteria, Acidobacteria, Planctomycetes, Nitrospirae, Verrucomicrobia (for abandoned lands) and Actinobacteria, Bacteroides, Firmicutes, Euryarchaeota (for soil in use).

Oxidation of methane by soil microorganisms is an important mechanism controlling the content of this potent greenhouse gas in the atmosphere. Agricultural soils operate under stressful conditions, and ammonium (N-fertilization) and drying (global warming) may have a significant impact on methane oxidation. In order to investigate how soil methanotrophs respond to drying–rewetting (DW), ammonium addition (100 mg/g) (A), and their combined action (MS), agricultural soil microcosms were incubated over the three months and methane oxidation was measured before and after perturbations, while community composition was monitoring using 16S rRNA gene sequencing. A significant decline in the methane-oxidation activity after perturbations was found, with subsequent restoration, and the combined treatment was more effective than the sum of individual treatments, indicating a synergistic effect. After rewetting, the structure of the bacterial community returned to pre-dry-down levels, but the application of ammonia and combined action lead to irreversible changes in the structure of soil methanotrophic communities. Methanotroph Methylomicrobium were significantly reduced under disturbances, while there was a significant increase in the representation of Methylobacter accompanied by the facultative methylotroph Methylovorus. We concluded that methanotrophic communities in agricultural soil demonstrated flexibility, and even when the abundance of dominant populations drops, ecosystem functions can recover.

Technogenic processes and agrodevelopment of the soil cover lead to significant transformations of soil chemical and biological properties. New methods of soil microbiology, including next-generation sequencing, allows us to investigate soil microbial composition in detail, including the taxonomy and ecological functions of soil bacteria. This study presents data on the taxonomic diversity of mature and anthropogenically disturbed soils in various ecosystems of Russia. Natural soils in the southern taiga (Leningrad region and Novgorod region), northern taiga (Komi republic), forest-tundra, and tundra (Nadym city and Salekhard city) were investigated using next-generation sequencing (16S rDNA amplicon sequencing). In each natural bioclimatic zone, anthropogenically disturbed quarry soils or agriculturally transformed soils were also investigated. It was found that Proteobacteria, Actinobateriota, Acidobateriota, Bacteroidota, Chroloflexi, Planctomycetota, Verrucomicrobiota and Firmicutes phyla were dominant in natural soils, with minor differences between agrosoils and mature soils. In the soils of quarries, there were revealed processes of declining diversity of microbiome communities and the replacement of them by bacterial communities, different from natural and agrogenic soils. Thus, the microbial community is the most sensitive indicator of anthropogenic soil amendments and can serve to assess the success of soil self-restoration after human intervention.

Crop rotation is one of the oldest and most effective methods of restoring soil fertility, which declines when the same plant is grown repeatedly. One of the reasons for a reduction in fertility is the accumulation of pathogenic and unfavorable microbiota. The modern crop rotation schemes (a set of plant species and their order in the crop rotation) are highly effective but are designed without considering soil microbiota dynamics. The main goal of this study was to perform a short-term experiment with multiple plant combinations to access the microbiological effects of crop rotation. It could be useful for the design of long-term crop rotation schemes that take the microbiological effects of the crop rotation into account. For the analysis, five plants (legumes: vetch, clover, and cereals: oats, wheat, and barley) were used. These five plants were separately grown in pots with soil. After the first phase of vegetation, the plants were removed from the soil and a new crop was planted. Soil samples from all 25 possible combinations of primary and secondary crops were investigated using v4-16S rDNA gene sequencing. It was shown that the short-term experiments (up to 40 days of growing) are effective enough to find microbial shifts in bulk soil from different plants. Both primary and secondary cultures are significant factors for the microbial composition of microbial soil communities. Changes are the most significant in the microbial communities of vetch soils, especially in the case of vetch monoculture. Growing clover also leads to changes in microbiota, especially according to beta-diversity. Data obtained can be used to develop new crop rotation schemes that take into account the microbiological effects of various crops.

Restoration of anthropogenically disturbed soils is an urgent problem in modern ecology and soil biology. Restoration processes in northern environments are especially important, due to the small amounts of fertile land and low levels of natural succession. We analyzed the soil microbiota, which is one of the indicators of the succession process is the soil. Samples were obtained from three disturbed soils (self-overgrown and reclaimed quarries), and two undisturbed soils (primary and secondary forests). Primary Forest soil had a well-developed soil profile, and a low pH and TOC (total organic carbon) amount. The microbial community of this soil had low richness, formed a clear remote cluster in the beta-diversity analysis, and showed an overrepresentation of Geobacter (Desulfobacteriota). Soil formation in clay and limestone abandoned quarries was at the initial stage, and was caused by both a low rate of mineral profile formation and severe climatic conditions in the region. Microbial communities of these soils did not have specific abundant taxa, and included a high amount of sparse taxa. Differences in taxa composition were correlated with abiotic factors (ammonium concentration), which, in turn, can be explained by the parent rock properties. Limestone quarry reclaimed by topsoil coverage resulted in an adaptation of the top soil microbiota to a novel parent rock. According to the CCA analysis, the microbial composition of samples was connected with pH, TOC and ammonium nitrogen concentration. Changes in pH and TOC were connected with ASVs from Chloroflexota, Gemmatimonadota and Patescibacteria. ASVs from Gemmatimonadota also were correlated with a high ammonium concentration.

The properties and functions of soils are largely determined by the amount of available organic matter, which is most significant for the vital activity of microorganisms. The influence of the content of soil available organic matter on the composition and functioning of the microbial community during the transformation of barley straw in the soil is considered. A soddy-podzolic soil (Umbric Albic Retisols (Abruptic)), layer 0–20 cm, was incubated (t 25°C, 60% TFC) for 4 months and a model soil with a reduced content of available organic matter was obtained. Next, a laboratory experiment was carried out with the introduction of barley straw into native and model soil. In dynamics (0, 7, 40, and 70 days), soil respiration, microbial biomass (SBI), the number of microorganisms, and the taxonomic composition of the microbial community (16S-rRNA sequencing) were analyzed. The quality of soil organic matter was assessed by the content of total organic carbon (Ctot) and its fractions: available (Cavail), water-soluble (Cwat), labile (Clab). It has been shown that in the model soil the amount of Cwat and Cavail decreases by half in the absence of significant differences in the content of Ctot. In addition, there was a visible deterioration in the aggregate structure of the soil and an acceleration in the transformation of straw in it (25% more than in the native one). The taxonomic composition of the soil bacterial community was influenced by the amount of available organic matter in the soil, the addition of straw, and the time of incubation. A decrease in the content of available organic matter changes the composition of the microbial community: the proportions of the phyla Acidobacteria and Firmicutes decrease, while the proportions of Actinobacteria, Bacteroidetes, Chloroflexi, Planctomycetes, and archaea increase. It was revealed that the dominant part (50% of the total) of the microbial community of the depleted soil is characterized by great diversity and oligotrophy. Indicators are proposed for comparing soils by the oligotrophy of the microbial community based on the taxonomic composition.

Processes of soil restoration in anthropogenically disturbed soils is an urgent topic in modern ecology and nature management. Being mediator between mineral soil composition and plant vegetation, soil microbial community is important factor of soil restoration processes. Analysis of main soil nutrition components followed by 16S amplicon sequencing are sufficient methods for primary analysis of novel locations. Here is the primary analysis in a novel location in Northwest Europe (Russia). Main nutrition parameters (pH, P, Na and NH4+) and 16S rDNA Illumina amplicons were explored in abandoned soils from sandy pit quarry (2 sites) and refractory clay mining dumps (4 sites).Microbial communities of mature soils and dumps are variable and different in terms both nutritional and microbial components. pH, N and TOC are strong predictors for microbial composition. Dumps of refractory clays pQ_2 are non-developed soils, highly acidic and form specific microbial community. Differences between dumps and mature soils in both pre-quaternary and quaternary soils are connected with specific bacterial taxa. Those taxa are connected more with plant composition, not the soil properties themselves. The exact changes in microbial community are unique for different soils and areas.

The collapse of collective farming in Russia after 1990 led to the abandonment of 23% of the agricultural area. Microbial biomass is a transit pool between fresh and soil organic matter; therefore, structural changes in soil microbial community determine the carbon cycle processes caused by self-restoration of arable lands after abandonment. Here, we assessed the influence of monthly changes in moisture and temperature on the bacterial community structure and abundance in Retisols under long-term abandoned cropland. Two periods with pronounced differences in bacterial properties were revealed: the growing period from March to September and the dormant period from October to February. The growing period was characterized by higher bacterial abundance and diversity compared to the dormant period. The relative abundances of the bacterial community dominants (Alpha-, Gamma- and Deltaproteobacteria, subgroup 6 of phylum Acidobacteria) did not change significantly over the year, either in total or active communities. The relative abundances of Bacteroidetes and Verrucomicrobia increased in the growing period, whereas Actinobacteria and Chloroflexi were more abundant in the dormant period. The microbial gene abundances positively correlated with soil and air temperature, but not with soil moisture. Thus, the seasonal dynamics of soil microbial communities are closely related to soil temperature and should be considered when assessing carbon cycles in abandoned lands.

The rhizosphere community represents an “ecological interface” between plant and soil, providing the plant with a number of advantages. Close connection and mutual influence in this communication allow to talk about the self-adjusting “plant-rhizosphere community” system, which should be be studied in connection. Diversity estimation is one of the ways of describing both bacterial and plant communities. Based on the literature, there are two assumptions of how the diversity of plant communities related to the diversity of bacterial communities: 1) an increase in the species richness of plants leads to an increase in the number of available micro-niches, and increasing of microbial diversity, 2) an increase in the species richness of plants is accompanied by the predominant development of bacteria from highly productive specific taxa and decreasing in the diversity of microorganisms. Experimental studies show controversial results. We analyzed field sites (rye crop field and two fallow sites), using DNA isolation of both the plant root mass (followed by sequencing of the ITS1 region) and rhizosphere microorganisms (followed by sequencing of the 16s rDNA V4 region). This allowed us to 1) accurately determine the abundance and taxonomic position of plant communities; 2) extract information about both plant and microbial communities from the same sample. There was no correlation between alpha-diversity indices of plants and rhizosphere communities. Alpha-diversity connection should be explored in similar plant communities, such as synusia. We hypothesize, that the significant differences in plant abundances lead to significant changes in exudation profiles, and the loss of diversity connection. The beta-diversity between rhizosphere communities and plant communities is highly correlated, in particular in terms of the abundance of taxa. This can be explained by a potential correlation (as reported in the literature) or by the presence of statistical artifacts.

Pedogenesis depends on multiple factors, such as climate, vegetation, topography, parent material. Some of these factors are zonal, meaning they are determined by climate zone. But some factors are intrazonal, meaning that it has the same impact on soil formation in different climate zones. One example is parent material. The other peculiar feature of a parent material is that it determines the rates of pedogenesis. In this regard, Rendzic Leptosols – are intrazonal slowly developing soils formed on a limestone bedrock. In this study we approached the dynamics of microbiome formation in a chronosequence of these soils collected in Crimean Peninsula using analysis of 16S rRNA gene libraries and quantitative PCR. The chronosequence included benchmark soil, 700 year-old soil from the ancient city of Eski-Kermen, 70 year-old soil from WWII trenches and 50 year-old soil from the open quarry screenings. Our research demonstrated that soil type on a limestone rock is the driving force behind microbiome shaping, without any apparent influence of its age. Dominant phyla for all soil sites were Actinobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, Thaumarchaeota, Planctomycetes, Verrucomicrobia and Firmicutes. Alpha diversity was similar across sites and tended to be higher in topsoil. Beta diversity showed that microbiomes diverged according to the soil site and the soil horizon. CCA analysis, in combination with PERMANOVA, linked differences in microbiomes to the nutrients associated with the soil horizon, and our analysis showed that the reactive component of the soil microbiome shifted simultaneously in both soil horizons between different soil sites. The work was supported by the grant of the Russian Scientific Foundation, project 17-16-01030.

The rhizosphere community represents an “ecological interface” between plant and soil, providing the plant with a number of advantages. Despite close connection and mutual influence in this system, the knowledge about the connection of plant and rhizosphere diversity is still controversial. One of the most valuable factors of this uncertainty is a rough estimation of plant diversity. NGS sequencing can make the estimations of the plant community more precise than classical geobotanical methods. We investigate fallow and crop sites, which are similar in terms of environmental conditions and soil legacy, yet at the same time are significantly different in terms of plant diversity. We explored amplicons of both the plant root mass (ITS1 DNA) and the microbial communities (16S rDNA); determined alpha- and beta-diversity indices and their correlation, and performed differential abundance analysis. In the analysis, there is no correlation between the alpha-diversity indices of plants and the rhizosphere microbial communities. The beta-diversity between rhizosphere microbial communities and plant communities is highly correlated (R = 0.866, p = 0.01). ITS1 sequencing is effective for the description of plant root communities. There is a connection between rhizosphere communities and the composition of plants, but on the alpha-diversity level we found no correlation. In the future, the connection of alpha-diversities should be explored using ITS1 sequencing, even in more similar plant communities—for example, in different synusia.

Rendzic Leptosols are intrazonal soils formed on limestone bedrock. The specialty of these soils is that parent rock material is more influential in shaping soil characteristics than zonal factors such as climate, especially during soil formation. Unlike fast evolving Podzols due to their leaching regime, Leptosols do not undergo rapid development due to the nature of the limestone. Little is known how microbiome reflects this process, so we assessed microbiome composition of Rendzic Leptosols of different ages, arising from disruption and subsequent reclamation. The mountains and foothills that cover much of the Crimean Peninsula are ideal for this type of study, as the soils were formed on limestone and have been subjected to anthropogenic impacts through much of human history. Microbiomes of four soil sites forming a chronosequence, including different soil horizons, were studied using sequencing of 16S rRNA gene libraries and quantitative PCR. Dominant phyla for all soil sites were Actinobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, Thaumarchaeota, Planctomycetes, Verrucomicrobia and Firmicutes. Alpha diversity was similar across sites and tended to be higher in topsoil. Beta diversity showed that microbiomes diverged according to the soil site and the soil horizon. The oldest and the youngest soils had the most similar microbiomes, which could have been caused by their geographic proximity. Oligotrophic bacteria from Chitinophagaceae, Blastocatellaceae and Rubrobacteriaceae dominated the microbiome of these soils. The microbiome of 700-year old soil was the most diverse. This soil was from the only study location with topsoil formed by plant litter, which provided additional nutrients and could have been the driving force of this differentiation. Consistent with this assumption, this soil was abundant in copiotrophic bacteria from Proteobacteria and Actinobacteria phyla. The microbiome of 50-year old Leptosol was more similar to the microbiome of benchmark soil than the microbiome of 700-year old soil, especially by weighted metrics. CCA analysis, in combination with PERMANOVA, linked differences in microbiomes to the joint change of all soil chemical parameters between soil horizons. Local factors, such as parent material and plant litter, more strongly influenced the microbiome composition in Rendzic Leptosols than soil age.

Self-overgrowing recovery of disturbed soils is one of important processes in reclamation of disturbed soils. Different types of anthropogenic disturbances followed by variety of soil types and their genesis leads to different bacterial communities, envolved in reclamation processes. Here we describe regional self-overgrowing soils in two location (Novgorod region, Northwest Russia). We analyse top level of industrial disturbed soils after coil mining (spoil tips with extremely low pH, and overburden soil) and sand quarry dumps followed by local undisturbed soils. We perform 16s amplicone sequencind (v4-region) by Illumina MiSEQ and chemical routine analysis (pH, C, N and other). We provide alpha- and beta-diversity analysis, followed by CCA and analysis of differential abundance of taxa. Sand quarry dumps and regional soils looks common on phyla level, and represent common soil phyla like Proteobacteria, Actinobacteria and Verrucomicrobia. Alpha-diversity metrics aslo are similar, despite difference in beta-diversity. Overburden soil and soil from spot tips, by contrast, is very different even in phylum level. Main intermediants here are Actinobacteria, Chloroflexi и Nitrospirae. Also they show extremely low alpha-diversity metrics. This work was supported by RSF 17-16-01030, «Dynamics of soil biota in chronoseries of post-technogenic landscapes: analysis of soil-ecological efficiency of ecosystem restoration processes»

Permafrost soils differ significantly from other soils because they serve as a huge reservoir for organic carbon accumulated during the Quaternary Period, which is at risk of being released as the Arctic warms. This study aimed to characterize existing carbon pools, delineate possible mineralization risks of soil organic matter and assess microbial communities in the tundra and forest–tundra permafrost soils of the southern Yamal region of Russia. The profile distribution of carbon, nitrogen and the C:N ratio showed non-gradual changes with depth due to the manifestation of cryopedogenesis in soil profiles, which lead to cryogenic mass transfer. Mean carbon stocks for the study area were 7.85 ± 2.24 kg m−2 (0–10 cm layer), 14.97 ± 5.53 kg m−2 (0–30 cm) and 23.99 ± 8.00 kg m−2 (0–100 cm). The analysis of the humus type revealed a predominance of fulvic type and low-molecular-weight fragments in the fulvic acid fraction, which indicates high mineralization risk of humic substances under Arctic warming conditions. The taxonomic analysis of soil microbiomes revealed 48 bacterial and archaeal phyla, among which proteobacteria (27%) and actinobacteria (20%) were predominant. The pH range and nitrogen accumulation were the main environmental determinants of microbial community diversity and composition in the studied soils.

Loss of tropical forests leads both to the loss of aboveground biodiversity and to the changes in belowground biological activity. Planted secondary forests return canopy cover, but the reversibility of belowground changes may depend on soil properties, forest age and tree species composition. We studied microbial communities in an array of soils in southern Vietnam under different vegetation: natural tropical forests, grasslands on deforested area and 20 and 30 years-old forest plantations. Conversion of natural forests into grasslands led to the loss of half of soil organic matter and microbial abundance, soil moisture decreased, bacterial community structure changed and beta-diversity increased. Bacterial alpha-diversity and pH were not affected by deforestation. Reforestation for 30 years restored bacterial and archaeal abundance, partially restored bacterial community structure, but did not restore fungal abundance and organic matter content. Thus, forest planting in southern Vietnam restores soil microbiome properties partially, but the complete restoration apparently requires much more than 30 years of secondary forest succession.

Polyethylene film is one of the most common types of recalcitrant plastic waste materials. Information regarding the fate of plastic films in soil is scarce compared to the fate of plastic films in aquatic environments. The aim of this study was to evaluate the effects of soil fauna and of impregnation of polyethylene films with oil on the colonization of low-density polyethylene films by prokaryotic communities. The field experiment was performed in a monsoon tropical forest (Vietnam). Polyethylene films were incubated in thermally pre-defaunated soil isolated from the surrounding soil by a stainless steel mesh. Three mesh sizes were used, allowing access to different size groups of soil fauna. The diversity, taxonomic structure and co-occurrence patterns in prokaryotic communities were studied using high-throughput sequencing of 16S rRNA gene libraries. The prokaryotic communities that formed on polyethylene films were slightly different from those inhabiting the surrounding soil. Contrary to our expectations, no difference in the diversity of prokaryotes was observed between microcosms with different mesh sizes. Oil impregnation also had only a minor influence on the prokaryotic community structure. Polyethylene films incubated in microcosms with soil appeared to be colonized by various consortia of prokaryotes as a barren and inert surface.