Количественные характеристики микробных сообществ современных морских донных отложений Восточного Мурмана

For the first time, the distribution of the total number and biomass of bacteria, the number of saprophytic bacteria and the size-morphological structure of bacteriobenthos in the suspended sediment of the Priplotinny Reach of the Kuibyshev reservoir were studied. The surface layer of the watered sediment (0.5-1 cm) was studied. The average number of bacteria in the suspended sediment is estimated at 5.19±1.52×109cells mL-1, biomass – 0.68±0.25 μg mL-1. The average number of saprophytic bacteria is 5.82±0.53×105 CFUmL-1. The size structure is dominated by bacterial cells with linear dimensions of 0.2-0.5 μmand a volume of 0.025-0.100 µm3.The dominant cellmorphotypeis rods.The percentage of coccobacilli is higher in the littoral, rods – in the profundal. A comparative analysis of bacteriobenthos in the suspended and in the bottom sediments (1-2 cm) was carried out. In the vertical profile,towards the bottom the total number and biomass of bacteria increases, the variability of the dominant size classes of bacteria increases, and by an order of magnitude the percentage of saprophytic bacteria decreases. Spatial distribution of bacteria in suspended sediment conserves the general pattern common for silts– an increase in the number and biomass of cells from upper reaches towards the dam. The exception is the headwater sectionwith increased hydrodynamic activity of bottom waters resulting in decreased quantities of bacteria in the suspended sediment compared to bottom sediment. The largest numbers of saprophytic bacteria on the shallow coast are concentrated in the bottom sediment, in the deep–water central zone of the reach – in the suspended sediment. The distribution of cocci in the upper sediment along the bottom is uniform and does not change with depth. In the bottom sediment cocci reach their greatest quantities in shallow waters, in deep-water biotopes their number decreases.

Characterization of phosphorus sorption and microbial community in lake sediments during overwinter and recruitment periods of cyanobacteria.

Vertical distribution of dissimilatory iron reducing communities in the sediments of Taihu Lake

Distribution, abundance and carbon isotopic composition of gaseous hydrocarbons in Big Soda Lake, Nevada: An alkaline, meromictic lake

Bacteria are a sensitive indicator of the state of the soil contaminated with oil and oil products. After the intro-duction of ameliorants, the oil content in the soil changes, which affects the number of bacteria. The aim is to estimate the number of bacteria in petroleum hydrocarbons contaminated Haplic Chernozem after amelioration. Biochar, sodium humate, nitroammophos, and microbiological fertilizer «Baikal EM-1» were added to petroleum hydrocarbons-contaminated Haplic Chernozem (5% petroleum hydrocarbons by weight of soil). After 90 days of the experiment, the number of bacteria in the soil was estimated by the total number of bacteria, determined by the method of luminescent microscopy, the number of actinomycetes, amylolytic and ammonifying bacteria, determined by the method of inoculation on solid nutrient media. The integral indicator of the number of bacteria (IINB) of the soil was calculated before and after the application of ameliorants. When introducing biochar, it is possible to use the total number of bacteria to assess the ecological state of the soil, with nitroammophoska — the number of ammonifying bacteria, sodium humate — the number of actinomycetes, «Baikal EM-1» — the number of amylolytic bacteria. According to the IINB of soils, the most effective dose for remediation with nitroammo-phoska, biochar, and Baikal EM-1 is D0.5, and for remediation with sodium humate, D2. It is advisable to use the results of the study in biodiagnostics and monitoring the state of petroleum hydrocarbons contaminated Haplic Chernozem after amelioration.

In this study, we evaluate the use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) for monitoring the effect of different aquaculture practices on sediment prokaryote (Archaea and Bacteria) communities. The effect of initial fish (gilthead seabream Sparus aurata) stocking density on the structural diversity of prokaryote communities of earth ponds bottom sediments was evaluated using PCR-DGGE after a 5 month grow-out period. An identical approach was used to monitor the effect of supplying different fish feeds [commercial feed (CD) versus an ecofeed (ECO)]. One additional variable was the use of copper sulphate (CuSO4) as an algicide in some of the experimental rearing tanks. The statistical analyses of prokaryote community profiles showed that the presence of fish in earth ponds significantly influenced the structure of sediment prokaryote communities, when compared with earth ponds without fish, independently of the stocking density. Our results also indicated that the structure of the prokaryote communities of earth ponds supplied with the ECO feed shared a strong similarity with that fed CD. Curiously, the use of CuSO4 in ponds receiving the ECO feed promoted significant differences on the structural composition of the bacterial community, but not on the archaeal community. DGGE molecular fingerprints are suitable for fast evaluation of new management practices in food-fish production on earth ponds by monitoring shifts on microbial communities in bottom sediments.

The article presents the results of a comprehensive study of the Soyana River for the first time. The characteristics of hydrological and hydrochemical parameters were obtained while observations in July 2020 and March 2021. Changes in the hydrogen index (pH), mineralization, and the content of dissolved oxygen and biogenic elements in water, as well as petroleum hydrocarbons in water and bottom sediments were studied using generally accepted in hydrochemical practice methods. The data obtained were evaluated for compliance with the regulatory requirements for the river water quality. According to the chemical composition, the Soyana River water belongs to the hydrocarbonate class of small and medium mineralization (164–296 mg/L), weakly acidic and slightly alkaline type (pH 6.0–8.2). The data obtained allow us to conclude that there is no noticeable anthropogenic impact on the considered watercourse. The petroleum hydrocarbons content in water and bottom sediments was below maximum permissible concentrations. In river water it was below 0.010 mg/L, in bottom sediments – in the range from 0.2 to 3.2 mg/kg. The maximum content of petroleum hydrocarbons in soils was recorded in the lower course of the river, where bottom sediments are presented in the form of silty sand. The interannual variability of hydrological and hydrochemical characteristics in the direction from the source to the mouth of the river is estimated. The relationship and regularity of their distribution was specified. The data obtained can serve as background data for assessing the negative impact in case of anthropogenic load on the river basin.

The Saihanba Mechanical Forest is an artificial national forest park with a forest-steppe landscape. The flora and fauna have been extensively studied, but a comprehensive understanding of the bacterial community composition and structure of the natural rainwater lakes present in the area has rarely been reported. In this study, the structure and functional characteristics of bacterial communities in lake sediments and water samples in the Saihanba artificial forest were investigated using 16s rRNA high-throughput sequencing. Microbial diversity analyses revealed that Proteobacteria, Acidobacteria, Bacteroidota and Verrucomicrobiota microbiota dominated. The abundance of Proteobacteria and Actinobacteriota was significantly higher (p < .05) in water samples compared to sediment samples. PICRUSt2 functional analysis predicted genes associated with the degradation of xenobiotics and the execution of essential metabolic processes. Here, we report differences in the composition of native bacterial communities in sediments and water under the Saihanba artificial forest and make functional gene predictions. This study provides a reference for further exploring the structure and functional characteristics of microbial communities in water samples and sediment environments of lakes under planted forests.

The Kamenka River flows through the territory of the Kokuy oil and gas field. A unique feature of this area is thepresence of karst processes in the underlying rocks. As a result, oil spreads in underground horizons over significant distances fromthe oil extraction sites and emerges on the soil surface and in riverbeds at locations not associated with the operation of oil wells. Theprolonged presence of petroleum hydrocarbons in soils and bottom sediments leads to successional changes in the composition ofcenoses. Microbial communities respond the fastest, which is due to the ecological plasticity of bacteria. This study examines thecomposition of bacterial communities in the bottom sediments of the Kamenka River. The analysis of microbiocenoses was performedbased on high-throughput sequencing data and classical microbiological methods, which allowed for the isolation of key ecologicaltrophic groups. Sampling was conducted at a site where petroleum hydrocarbons emerged into the riverbed, as well as upstream anddownstream. The concentration of oil in the collected samples ranged from 2.4 to 25.8 g/kg. It was found that the dominant phylotypesin the studied communities were representatives of Proteobacteria (16.7–30.3%), among which the classes Alphaproteobacteria (3.2–8.7%) and Gammaproteobacteria (13.4–21.5%) were identified. The microbial community at the site of oil hydrocarbons’ emergenceexhibited the highest phylogenetic diversity, according to the values of Shannon and Simpson indices. It has been established that thereexists a core group of microorganisms that forms the basis of the microbiocenoses in this study area and a variable group whosecomposition depends on selective factors changing along the river's flow. In the microbial communities, the proportion of oil-degradingmicroorganisms varied from 0.02% to 16.0% and was in direct correlation with the concentration of hydrocarbons in the bottom sediments. An analysis of the metabolic potential of cultivated microorganisms revealed the presence of aerobic bacteria capable of utilizingaromatic compounds as a carbon source.

湖泊沉积物微生物是水生态系统的重要组成部分，目前关于丹江口库区沉积物细菌群落和功能研究鲜见报道.于2017年5月对丹江口库区内5个典型生态点位表层沉积物进行采集，采用高通量测序技术对表层沉积物细菌群落组成进行研究，结果表明细菌群落主要由变形菌门（Proteobacteria）、绿弯菌门（Chloroflexi）、拟杆菌门（Bacteroidetes）、疣微菌门（Verrucomicrobia）和硝化螺旋菌门（Nitrospirae）等33个门和318个属组成，具有丰富的群落组成.沉积物细菌群落和理化指标冗余分析（RDA）结果表明，pH值、总磷、有机质和铵态氮含量均能显著影响沉积物细菌群落组成.细菌属分类单元与环境因子Spearman相关分析表明，变形菌门中11个属的细菌与环境因子显著相关，为与环境因子显著相关细菌的主要组成（占47.62%）.采用细菌群落功能预测软件PICRUSt（Phylogenetic Investigation of Communities by Reconstruction of Unobserved States）对表层沉积物细菌群落进行分析，结果表明沉积物细菌功能主要涉及能量产生和转换、信号转导机制、氨基酸运输和代谢、细胞壁/细胞膜/膜结构的生物合成等24个基因功能家族，表现出功能上的丰富性.基因功能家族预测基因拷贝数表现为台子山 > 宋岗 > 库心 > 渠首 > 黑鸡嘴.;Sediment microbial communities play crucial roles in biogeochemical cycles of aquatic systems, and knowledge of microbial community structure could improve our understanding of these roles. To the best of our knowledge, there is no study revealing the compositions and functions of bacterial communities in sediments of the Danjiangkou Reservoir so far. In this study, 5 surface sediment samples were collected from the reservoir in May 2017. High-throughput sequencing was performed to analyze the distribution characteristics of the community structure and diversity of bacteria, and their relationship with environmental factors. Phylogenetic analysis based on 16S rDNA sequences showed that bacterial communities could be divided into 33 major phylogenetic groups. The dominant phylogenetic groups included Proteobacteria, Chloroflexi, Bacteroidetes, Verrucomicrobia, Nitrospirae, Acidobacteria, Planctomycetes and Omnitrophica. The results of redundancy analysis (RDA) for the relationship between the 33 bacterial phyla and 7 environmental factors showed that the pH, total phosphorus, sediments organic matter, and ammonium nitrogen were the main environmental factors affecting the distribution characteristics of the bacterial community. Spearman correlation analysis was employed to explore associations between all bacterial genera and environmental factors; the genera significantly correlated with the environmental factors mainly belonged to the phylum Proteobacteria. PICRUSt was used to understand the metabolic and functional abilities of the observed bacterial communities. The results obtained showed wide genetic diversity of organisms involved in various essential processes, such as energy production and conversion, signal transduction mechanisms, amino acid transport and metabolism, cell wall/membrane/envelope biogenesis, translation, ribosomal structure and biogenesis, replication, recombination and repair. The surface sediments of the Danjiangkou Reservoir can be ranked in the following order based on the 16S rRNA gene copy number of the detected phylotype:Taizishan > Songgang > Kuxin> Qushou > Heijizui.

Проанализирована годовая динамика: 1) содержания хлороформ-экстрагируемых веществ (ХЭВ) и нефтяных углеводородов (НУ) в прибрежных речных наносах, в донных отложениях зоны смешения речных и морских вод и в донных отложениях морской акватории; 2) численности углеводородокисляющей (УОБ) и гетеротрофной (ГБ) групп бактерий в донных отложениях морского участка и речных прибрежных наносах. Максимальное содержание ХЭВ выявлено в морской акватории (450±17.5 мг/100 г), минимальное – в речной части (127.6±10.9 мг/100 г), в зоне смешения речных и морских вод – 370±37.9 мг/100 г. Средние концентрации НУ распределены аналогично концентрациям ХЭВ: максимальные величины (127.5±10.9 мг/100 г) в морских грунтах, в осадках зоны смешения – несколько ниже (103.1±9.4 мг/100 г) и минимальные значения (54.8±23.9 мг/100 г) в речных наносах. Дана физико-химическая характеристика донных отложений и прибрежных наносов. Численность ГБ варьировала от 7.5•103 до 2.5•106кл/г в донных отложениях морского участка, от 9.5•103 до 9.5•108кл/г – речного. Сезонная изменчивость количественных показателей ГБ на обоих участках не отмечена. Бактерии, окисляющие нефтяные углеводороды, высеяны в 100 % проб донных отложений и прибрежных наносов обозначенных акваторий. Численность УОБ в морской зоне варьировала от 25 до 2.5•104 кл/г, речной – от 25 до 4.5•103 кл/г. В прибрежных наносах реки максимальные показатели численности УОБ отмечены в паводковый период (февраль–апрель). The annual dynamics of (1) chloroform-extractable substances (CES) and petroleum hydrocarbons (PH) in riverside fluvial sediments, in the bottom sediments of the mixing zone of river and sea waters, and in the bottom sediments of the marine area, and (2) the abundance of hydrocarbon-oxidizing (HOB) and heterotrophic (HB) bacterial groups in the bottom sediments of the marine area and riverside sediments is analysed. The maximal content of CES was found in the marine area (450±17.5 mg/100 g), and the minimal one − in the river part (127.6±10.9 mg/100 g), in the mixing zone of river and sea waters − 370±37.9 mg/100 g. The average concentrations of PHare distributed similarly to the concentrations of CES: the maximal values (127.5±10.9 mg/100 g) are detected in marine ground, the values for the sediments of the mixing zone are slightly lower (103.1±9.4 mg/100 g), and the minimal values (54.8±23.9 mg/100 g) are detected in river sediments. The physicochemical characteristics of bottom and coastal sediments are presented. The abundanceof HB in the bottom sediments of the marine area varied from 7.5∙103to 2.5∙106cells/g, respectively, and from 9.5∙103to 9.5∙108cells/g in the river area. There was no seasonal variability in the abundanceof HB at both areas. Hydrocarbon-oxidizing bacteria were registered in 100 % of the samples of bottom and riverside sediments of the designated water areas. The abundance of HOB varied from 25 to 2.5∙104cells/g in the marine zone and from 25 to 4.5∙103cells/g in the river zone. The maximal values of HOB abundance in the riverside sediments were recorded during the flood period (February–April).

The annual dynamics of (1) chloroform-extractable substances (CES) and petroleum hydrocarbons (PH) in riverside fluvial sediments, in the bottom sediments of the mixing zone of river and sea waters, and in the bottom sediments of the marine area, and (2) the abundance of hydrocarbon-oxidizing (HOB) and heterotrophic (HB) bacterial groups in the bottom sediments of the marine area and riverside sediments is analysed. The maximal content of CES was found in the marine area (450±17.5 mg/100 g), and the minimal one - in the river part (127.6±10.9 mg/100 g), in the mixing zone of river and sea waters - 370±37.9 mg/100 g. The average concentrations of PH are distributed similarly to the concentrations of CES: the maximal values (127.5±10.9 mg/100 g) are detected in marine ground, the values for the sediments of the mixing zone are slightly lower (103.1±9.4 mg/100 g), and the minimal values (54.8±23.9 mg/100 g) are detected in river sediments. The physicochemical characteristics of bottom and coastal sediments are presented. The abundance of HB in the bottom sediments of the marine area varied from 7.5•103 to 2.5•106 cells/g, respectively, and from 9.5•103 to 9.5•108 cells/g in the river area. There was no seasonal variability in the abundance of HB at both areas. Hydrocarbon-oxidizing bacteria were registered in 100 % of the samples of bottom and riverside sediments of the designated water areas. The abundance of HOB varied from 25 to 2.5•104 cells/g in the marine zone and from 25 to 4.5•103 cells/g in the river zone. The maximal values of HOB abundance in the riverside sediments were recorded during the flood period (February-April).

Bacterial biodiversity in deep-sea sediments from two regions of contrasting surface water productivity near the Crozet Islands, Southern Ocean

Marine oil spill pollution was one of the factors affecting the marine ecology of the northeastern South China Sea (nSCS). The submarine oil produced after the oil spill had a long-term impact on the microbial community in the sediment. In this study, 16S rRNA genes high-throughput sequencing and quantitative PCR were used to study the composition and distribution of bacterial communities in deep-sea sediments; meanwhile, petroleum hydrocarbon degrading bacteria were isolated, of which activity were detected. Proteobacteria and Planctomycetota were the main bacterial phyla found in the samples studied in this study. 29 bacterial strains capable of degrading petroleum hydrocarbons were isolated from S02 and S39 sediment samples, belonging to genus Stenotrophomonas, Pseudidiomarina, Sulfitobacter, Pseudomonas, Halomonas and so on. Strains from Stenotrophomonas degraded petroleum hydrocarbons efficiently. This research provided new insights into distribution pattern of benthic microbial community in the nSCS, and validated the degradation potential of petroleum hydrocarbons by indigenous bacteria.

Heavy metal pollution in lakes is an issue that endangers ecosystems worldwide; however, the vertical properties of heavy metals in the water columns and sediment cores of lakes have been rarely evaluated simultaneously. This study revealed the pollution, risks, and sources of heavy metals from surface water to deep sediments in four typical shallow lakes located in central China. The results showed that the concentrations of heavy metals, except Hg, had insignificant stratification in the water column. Heavy metals had three vertical profiles in sediment cores, i.e., the concentrations of As, Hg, Cd, Pb, and Mn in the surface sediment (0-9 cm) were higher than that in the bottom sediment (9-45 cm) (p < 0.05), the concentrations of Cr, Co, Fe, and Ni in the bottom sediment were higher than the surface sediment (p < 0.05), and the concentrations of Cu and Zn had no significant stratification. The Nemerow pollution index showed that heavy metal pollution dominated by Hg reached slight-moderate levels, and had higher levels in surface water than that in bottom water (p < 0.05). The Nemerow integrated risk index showed that the heavy metals had moderate-extreme potential ecological risks (Cd contributed 43.4%) in the sediments, and the ecological risk in surface sediment was significantly higher than that in bottom sediment (p < 0.01). Principal component analysis revealed that agriculture, transportation, and chemical industry were the major sources of heavy metals in water and surface sediments, while agriculture and steel-making were the primary sources in bottom sediments. This study provides valuable data and insight for the control of heavy metal pollution in lakes with high human activity loads.