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Simple Summary: The air microbiome is one of the most poorly characterized microbial communities of environmental objects. It has been suggested that leaves are indicators of air quality. In the present work, the taxonomic and functional diversity of bacterial and fungal communities, PAHs, and metal contents in PM100 of leaves and PM10 of air collected from two zones with different levels of anthropogenic pollution were compared. Dust particles found on the surface of leaves and air filters were also compared using scanning electron microscopy. Our data showed that air pollution had a greater effect on phylloplane bacterial communities. The effect of air pollution on bacterial communities could facilitate their use as indicators for monitoring atmospheric conditions. At the same time, bacterial organisms are performers whose role in biotechnological methods of air purification is inevitably important. Identifying the relationship between the microbiomes of urban dust particles from different biotopes is important because the state of microorganisms can be used to assess the quality of the environment. The aim of this work was to determine the distribution and interaction patterns of microorganisms of dust particles in the air and on leaf surfaces. Metabarcoding of bacterial and fungal communities, PAH, and metal content analyses and electron microscopy were used in this work. The results obtained allowed us to characterise the biological and chemical components of the dust particles. Some bacterial and fungal genera were correlated with benzanthracene, fluoranthene, and Cu, Ni, Co, Zn, and Mn contents. Bacterial communities were found to be more sensitive to all the pollutants studied. PM10 microbial communities circulated between biotopes and study areas due to air flows, as evidenced by the presence of similar ASVs in fungi and bacteria. The results could help to understand the effects of climate change and anthropogenic activities. [ABSTRACT FROM AUTHOR]

The impact of geographical factors, functional zoning, and biotope type on the diversity of microbial communities and chemical components in the dust of urban ecosystems was studied. Comprehensive analyses of bacterial and fungal communities, polycyclic aromatic hydrocarbons (PAHs), and metals in road and leaf dust in three urban zones of Murmansk and Moscow with contrasting anthropogenic load were conducted. We found that the structure of bacterial communities affected the functional zoning of the city, biotope type, and geographical components. Fungal communities were instead impacted only by biotope type. Our findings revealed that the structure of fungal communities was mostly impacted by PAHs whereas bacterial communities were sensitive to metals. Bacteria of the genus Sphingomonas in road and leaf dust as indicators of the ecological state of the urban ecosystems were proposed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Deicing agents cause soil salinization and degradation in urban areas. We assessed the capacity of urban lawns to maintain carbon sequestration and nutrient cycling with increasing soil salinity. The sensitivity to soil salinity of the main ecosystem players: plants and microorganisms were assessed considering their complex interactions between each other and environment. The effects of low and moderate soil salinization by common deicing agent (NaCl) were evaluated in mesocosms planted with two urban lawns: Lolium perenne and mixture of grasses. Mesocosm‐, plant‐, and soil‐level gas exchange were assessed on a short‐term (days) and long‐term (months) scales. Microbial response was characterized by analyzing the microbial properties and activities of nine enzymes. Carbon balance remained independent on the salinity due to cancelling effect of lowered gross primary production (GPP, −20%), decreased C input by plants into the soil (−40% for mixture) balanced by slower microbial decomposition of organic matter (−20%) and so, lower soil respiration (−35%). GPP declined as a long‐term response by a combination of stomatal constraint on photosynthesis with leaf respiration increase. Toxic effects of salinization on soil respiration were observed only for temperatures above 15°C. Microbial community with high C:N ratio (common for fungi) was the most sensitive to salinization. The death of microbial biomass (−31% for Lolium) and cell lysis increased soil enzyme activities (+38% for Lolium). We conclude that C balance of urban lawns remain homeostatic at secondary salinization. Temperature effects and plant‐microbial interactions will determine C and nutrients cycling under salinity stress in urban lawns. [ABSTRACT FROM AUTHOR]

Purpose: Journal of Soils and Sediments publishes the main outcomes of SUITMA 9 Conference in its Special Issue. SUITMA (Soils of Urban, Industrial, Traffic, Mining and Military Areas) working group organizes conferences biannually all over the world. The ninth conference organized in Moscow in May 2017 involved more than 215 speakers from 25 countries, whose presentations focused on challenges and opportunities of urbanization for soil functions and ecosystem services. Materials and methods: The main outcomes of SUITMA 9 were analyzed in comparison to the previous SUIMTA conferences and the main topics were distinguished. Manuscripts accepted for publishing in the Special Issue were reviewed and presented. Results and discussion: Comparison of the topics highlighted in different special issues highlighted the evolution of the SUITMA studies from fundamental morphological descriptions and classifications to applied studies on soil engineering, assessment of SUITMA functions and ecosystem services. Conclusions: The manuscripts accepted to the Special Issue covered included various case studies of SUITMA ecosystem services (e.g. global and local climate regulation, biodiversity maintenance and improvement, nutrients balance and recreation) and disservices (e.g. pollution by heavy metals, polycyclic aromatic hydrocarbons and sulfur). The increasing role of SUITMA studies for urban management and decision making was concluded. [ABSTRACT FROM AUTHOR]

The phylloplane is an integrated part of green infrastructure which interacts with plant health. Taxonomic characterization of the phylloplane with the aim to link it to ecosystem functioning under anthropogenic pressure is not sufficient because only active microorganisms drive biochemical processes. Activity of the phylloplane remains largely overlooked. We aimed to study the interactions among the biological characteristics of the phylloplane: taxonomic diversity, functional diversity and activity, and the pollution grade. Leaves of Betula pendula were sampled in Moscow at increasing distances from the road. For determination of phylloplane activity and functional diversity, a MicroResp tool was utilized. Taxonomic diversity of the phylloplane was assessed with a combination of microorganism cultivation and molecular techniques. Increase of anthropogenic load resulted in higher microbial respiration and lower DNA amount, which could be viewed as relative inefficiency of phylloplane functioning in comparison to less contaminated areas. Taxonomic diversity declined with road vicinity, similar to the functional diversity pattern. The content of Zn in leaf dust better explained the variation in phylloplane activity and the amount of DNA. Functional diversity was linked to variation in nutrient content. The fraction of pathogenic fungi of the phylloplane was not correlated with any of the studied elements, while it was significantly high at the roadsides. The bacterial classes Gammaproteobacteria and Cytophagia, as well as the Dothideomycetes class of fungi, are exposed to the maximal effect of distance from the highway. This study demonstrated the sensitivity of the phylloplane to road vicinity, which combines the effects of contaminants (mainly Zn according to this study) and potential stressful air microclimatic conditions (e.g., low relative air humidity, high temperature, and UV level). Microbial activity and taxonomic diversity of the phylloplane could be considered as an additional tool for bioindication. [ABSTRACT FROM AUTHOR]

For the first time, a mycological analysis of outdoor urban environment (air, leaves, sealed surfaces) was carried in the cities of subarctic (Murmansk) and temperate (Moscow) climatic zones. The chemical composition of dust deposited on leaves of dominant tree species was taken as an indicator of the air quality. Assessment of the complex impact of factors (climate zone, type of substrate, anthropogenic load) on the quantitative and qualitative parameters of mycobiome was performed. Compared to Moscow, Murmansk was characterized by an increased number and concentrations of pollutants in the deposited dust. The number of culturable airborne fungi in Murmansk was substantially lower than in Moscow. Half of the species belonged to the opportunistic in both cities. Most dangerous opportunistic fungi were absent in the air of recreational zones but present on leaves surface and in road dust in all assessed zones of the cities. Dust chemical composition affected the diversity of fungi species. While the relationship of biological parameters with concentration of potentially toxic metals was generally negative, Cd increased the fraction of opportunistic fungi in road dust. The study revealed an importance of substrate in determining the sensitivity of outdoor mycobiome to pollution and highlighted its biological characteristics sensitive to climate. [ABSTRACT FROM AUTHOR]