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Groundwater, which appears on the surface in the form of springs, is an important ecologically significant component of the aquatic ecosystem, sensitive to changes in environmental conditions. The anthropogenic impact associated with urbanization leads to a change in the characteristics of groundwater, which, in turn, affects the composition of microbial communities in spring waters. Using high-throughput sequencing of the 16S ribosomal RNA gene fragments, we characterized the composition of microbial communities in five natural springs in the city of Moscow in the spring, summer, and winter seasons. The microbial communities of each spring in different seasons were similar to each other and clearly differed from the microbiomes of the other springs. Among the Archaea, which averaged about 20% of the microbial communities, ammonium-oxidizing Crenarchaeota predominated, as well as Nanoarchaeota. Most of the Bacteria belonged to the phyla Proteobacteria, Patescibacteria, Verrucomicrobiota, Chloroflexi, and Bacteroidota. Autotrophic bacteria, including iron-oxidizing bacteria of the family Gallionellaceae and nitrifiers, as well as methanotrophs, accounted for significant proportions in the microbial communities of the springs with a presumably deeper water source. Chemical and molecular analyses did not reveal contamination of spring waters with toxic substances and oil-derived products, as well as the presence of pathogenic microorganisms and indicators of fecal pollution. However, during the spring season, the proportions of halophilic and hydrocarbon-oxidizing bacteria increased in water microbiomes, which may reflect the entry into groundwater after snow thawing of deicing reagents and hydrocarbons, which are successfully biodegraded in the soil. [ABSTRACT FROM AUTHOR]

The effect of introduction of exogenous activated sludge (bioaugmentation) on the activity and composition of the microbial consortium carrying out the nitritation-anammox process in an SBR bioreactor was investigated. Two bioaugmentation strategies were tested: the exogenous sludge was added either immediately after inoculation with the anammox activated sludge or when the stable mode of nitrogen removal was achieved. The share of introduced sludge (by the amount of volatile dry matter) was 28‒35% of the total activated sludge mass. The growth conditions and community composition for activated sludges differed significantly: members of the genera "Candidatus Brocadia" and "Ca. Jettenia" were predominant in the aboriginal sludge, while "Ca. Kuenenia" and "Ca. Jettenia" predominated in the exogenous one. While bioaugmentation at the time of launching resulted in a 15% increase in nitrogen removal efficiency, this positive effect was short-lived (by day 46 of cultivation, the values of nitrogen removal efficiency in the control and experimental reactors were the same). Addition of exogenous activated sludge after the stable nitrogen removal mode was reached (day 53) increased the efficiency of nitrogen removal by 21‒35%, and this difference was maintained until the end of the experiment (90 days). The introduced anammox bacteria did not get acclimatized in the community of the SBR reactor; whatever was the method of their introduction, their abundance decreased to the minimum values. Our data indicate that the efficiency of nitrogen removal by the nitritation-anammox process may be enhanced by introduction of activated sludges differing in both the composition and the cultivation conditions from the aboriginal ones, either at reactor launching or into an actively operating bioreactor. [ABSTRACT FROM AUTHOR]

The microbiota of chicken litter remains largely unexplored, despite its leading role in the formation of volatile odorants and unpleasant odors. One of the main components of the odor is hydrogen sulfide, which may be formed as a result of microbial sulfate reduction. The composition of the microbial community of poultry plant waste was investigated. Samples were collected at the Mezheninovskaya large poultry farm, 15 km from the city of Tomsk, Russia. The 16S rRNA gene profiling revealed sulfate-reducing Desulfovibrionaceae in the microbial community. Both their share in the community and sulfide production increased upon incubation of the waste in the medium with sulfate and lactate. The possible sulfate sources in the waste are gypsum and the feed additives introduced as sulfates, such as lysine sulfate. [ABSTRACT FROM AUTHOR]

The composition of the microbiome of acid drainage water of a quarry used for the mining of brown coal was studied. The water had a pH of 5.15 and contained 1.4 g/L of sulfate. Unlike acid mine drainage associated with mining of sulfide ores, the content of iron and heavy metals was low. Molecular analysis of the microbial community was performed by high-throughput sequencing of the 18S and 16S rRNA gene fragments. Most eukaryotic sequences belonged to the fungal phylum Basidiomycota; members of the Chytridiomycota were also found. Basidiomycetes of the family Sporidiobolaceae were the predominant group, as was previously reported for acid mine drainage waters. Among the minor groups, protozoa (Alveolata and Amoebozoa) and green algae (Chlamydomonas) were found. The dominant group of prokaryotes was the genus Acidiphilium (Alphaproteobacteria); betaproteobacteria of the genera Sulfuriferula and Thiomonas were also found. [ABSTRACT FROM AUTHOR]

Changes in microbial community composition during formation of an acid mine drainage were studied on a model of two water reservoirs located in the Ozernoye open-cast mine for polymetallic ores in Eastern Siberia. The first reservoir, Bu-18, was filled with groundwater, had a neutral pH and low levels of sulfate and dissolved metal ions. The second reservoir, Bu-16, was an acid mine drainage (pH 2.85) filled with the water from Bu-18, which passed through rocks containing sulfide minerals. The Bu-16 water contained 1405 mg/L of sulfate, 164 mg/L of manganese, 78 mg/L of magnesium, and 26 mg/L of iron. Molecular analysis of the microbial communities of two reservoirs, carried out using high-throughput sequencing of the 16S rRNA gene fragments, showed that formation of the acid mine drainage was accompanied by a decrease in microbial diversity and by selection of several dominant taxonomic and functional groups. Chemolithoautotrophic iron- and sulfur-oxidizing bacteria of the genera Leptospirillum, Acidithiobacillus, Gallionella, Sulfuriferula, and Sulfobacillus constituted most of the prokaryotic community in Bu-16. Heterotrophic bacteria of the genera Ferrimicrobium and Metallibacterium, capable of reducing Fe(III) under anaerobic conditions, were present as minor components. Over 20% of the community were members of the Candidate Phyla Radiation group and of the candidate phylum Dependentiae (TM6), known for their parasitic or symbiotic lifestyle. These groups of bacteria were rarely found in acid mine drainage and only in minor quantities. Potential hosts of the Dependentiae, flagellates of the genus Spumella, were found among eukaryotes in Bu-16. [ABSTRACT FROM AUTHOR]