Microbial Community Structure Characteristics Research Articles

Characteristics of microbial community structure and influencing factors of Yangcheng Lake and rivers entering Yangcheng Lake during the wet season.

Yangcheng Lake, a typical fishery lake in the middle and lower reaches of the Yangtze River, is threatened by eutrophication. As the main performers of biogeochemical cycles, microorganisms affect the ecological stability of the lake. To study the structural characteristics of the microbial community in Yangcheng Lake and rivers entering Yangcheng Lake and the response relationship with environmental factors, the microbial community was categorized based on the contour of Yangcheng Lake, the major rivers entering Yangcheng Lake, and the pollution sources. The distribution characteristics of seven physicochemical indices were analyzed, including total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), water temperature (WT), pH, dissolved oxygen (DO), and ratio of total nitrogen to total phosphorus (TN/TP). Characterization of microbial community structure based on 16S rRNA high-flux sequencing technology and ANOSIM analysis were used to explore the differences in the relative abundance of microorganisms at each sampling point in the lake and rivers, and redundancy analysis (RDA) was used to analyze the relationship between the microbial community and physicochemical factors. The results showed that the dominant phyla, genera of microorganisms, and the total number of OTUs in the lake and rivers were similar. The dominant phyla included Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Verrucomicrobia; the dominant genera included the hgcI clade, CL500-29 marine group, Microcystis PCC-7914, Chloroplast_norank, Clade III_norank, and Flavobacterium. ANOSIM analyses revealed that the microbial community of Yangcheng Lake exhibited an association with geographical space, while the microbial community in the rivers that was linked to the type of pollution source. Redundancy analysis (RDA) indicated that dissolved oxygen (DO), total nitrogen (TN), and pH were significantly correlated with the dominant phyla in Yangcheng Lake (p < 0.05), while total nitrogen (TN), water temperature(WT), and the ratio of total nitrogen to total phosphorus (TN/TP) were significantly related with the dominant genera in Yangcheng Lake (p < 0.05). Total nitrogen (TN) was also significantly linked to the dominant phyla and genera of the tributaries (p < 0.05). Despite the structural similarities in microbial communities between Yangcheng Lake and its inflowing rivers, environmental factors demonstrated significant associations with these communities, providing crucial data support for pollution prevention and the ecological restoration of Yangcheng Lake.

Microbial community structure characteristics and gene distribution of sulfur-siderite/limestone autotrophic denitrification

Microbial community structure and functional gene of sulfur-siderite/limestone autotrophic denitrification (SSAD/SLAD) systems were comprehensively investigated in bath bioassays by microbiological approaches. High-throughput sequencing analysis showed that there were abundant sulfur autotrophic denitrifying bacteria in both systems, with the dominant genera being Sulfurimonas, Thiomonas, Thiobacillus and Acidithiobacillus. A remarkably higher Thiobacillus abundance in SSAD system was probably because of the presence of Fe2+, while Ignavibacterium, Desulfocapsa and Chlorobium were markedly more active in SLAD system, which could be closely related to its higher concentration of sulfide. Analysis of macrogenome sequencing inferred that the main functional genes implicated in the denitrification process included nrtABC, nar, napAB, nosZ, norBC and nirSK, endowing excellent denitrification efficiency of systems. Meanwhile, the genes involved in sulfate reduction mainly included apr, dsr and sat genes, and sox and dsr participated in sulfur oxidation process. This study provided insights into mechanisms and reliable application of sulfur autotrophic denitrification.

Microbial community structure characteristics among different karst aquifer systems, and its potential role in modifying hydraulic properties of karst aquifers.

Little is known about how microbial activity affects the hydraulic properties of karst aquifers. To explore the potential impacts of microbial activity on the hydraulic properties of karst aquifers, microbiological analysis, heat tracer, isotope (dissolved inorganic carbon isotope, δ13CDIC) and aqueous geochemical analyses were conducted at six monitoring wells in Northern Guangdong Province, China. Greater hydraulic conductivity corresponded to a low temperature gradient to an extent; the temperature gradient in karst groundwater aquifers can reflect the degree of dissolution. Higher HCO3 - concentrations coupled with lower d-excess and pH values at B2 and B6 reflect potential microbial activity (e.g., Sulfuricurvum kujiense) causing carbonate dissolution. Microbial activity or the input of anthropogenic acids, as evidenced by significantly more positive δ13CDIC values, potentially affect carbonate dissolution in deep karst aquifers, which eventually alters hydraulic properties of karst aquifer. However, more direct evidence is needed to quantify the effects of microbial activity on carbonate dissolution in karst aquifers.

Purification effects of recycled aggregates from construction waste as constructed wetland filler

Three groups of constructed wetlands based on gravel (#1), asphalt concrete + red brick (#2), and red brick (#3) were constructed to explore their purification effects and the characteristics of microbial community structure. The results show that the construction waste recycled aggregates have little leaching risk of heavy metals; the adsorption of nitrogen and phosphorus by the three fillers could be well fitted by pseudo-first-order and pseudo-second-order kinetic models (R2 > 0.96); the adsorption of NH4+-N by the three fillers could be well fitted by the Freundlich model (R2 > 0.656); the adsorption of phosphorus could be well fitted by the Langmuir and Freundlich models, except for gravel (R2 > 0.875). The average removal rate of COD, NH4+-N, TN, and TP was 60.85 %, 94.69 %, 73.42 %, 39.12 % (#1); 67.32 %, 20.31 %, 22.26 %, 27.81 % (#2); 67.35 %, 17.7 %, 25.8 % and 46.98 % (#3). There was no significant difference in the purification effect of the three fillers on COD. The adsorption effect on NH4+-N was: gravel > red brick/asphalt concrete, and the adsorption effect on TP was: asphalt concrete > red brick > gravel. The microbial population richness of the upper filler was #2 > #1 > #3, the uniformity was #1 > #2 > #3, and the diversity was #1/#2 > #3. The microbial communities were dominated by Proteobacteria, Actinobacteriota, Bacteroidota and Chloroflexi.

Nitrogen Distribution and Soil Microbial Community Characteristics in a Legume–Cereal Intercropping System: A Review

Intercropping systems can flexibly use resources such as sunlight, heat, water, and nutrients in time and space, improve crop yield and land utilization rates, effectively reduce continuous cropping obstacles and the occurrence of diseases and insect pests, and control the growth of weeds. Thus, intercropping is a safe and efficient ecological planting mode. The legume–cereal intercropping system is the most common planting combination. Legume crops fix nitrogen from the atmosphere through their symbiotic nitrogen fixation abilities, and the fixed nitrogen can be transferred to and utilized by cereal crops in various ways. The symbiotic nitrogen fixation efficiency of legume crops was improved by reducing the inhibition of soil nitrogen on nitrogenase activity through competitive absorption of soil nitrogen. However, the effects of nitrogen transformation and distribution in intercropping systems and microbial community structure characteristics on nitrogen transfer need to be further explored. In this review, (ⅰ) we present the transformation and distribution of nitrogen in the legume–cereal intercropping system; (ⅱ) we describe the soil microbial community characteristics in intercropping systems; and (ⅲ) we discuss the advantages of using modern biological molecular techniques to study soil microorganisms. We conclude that intercropping can increase the diversity of soil microorganisms, and the interaction between different plants has an important impact on the diversity and composition of the bacterial and fungal communities. The extensive application of modern biological molecular techniques in soil microbial research and the great contribution of intercropping systems to sustainable agriculture are particularly emphasized in this review.

Characteristics of Microbial Community Structure in the Surrounding Farmlands of a Mercury Mining Area and Its Environmental Driving Factors

In order to investigate the characteristics of soil microbial community structure and their relationships with environmental factors in the surrounding farmlands of a mercury mining region, we analyzed soil physical and chemical properties, Hg pollution, enzyme activity, and microbial community structure characteristics in the surrounding farmlands of a mercury mining region in Tong Ren (Bahuang Town, Bijiang District; Huaqiao Town, Shiqian County; Kaide Town, Jiangkou County; and Chuantong town, Bijiang District; referred to as BJ, SQ, JK, and TR, respectively). The relationships between the characteristics of soil microbial community structure and environmental factors were determined using redundancy analysis (RDA) and correlation network analysis. The results showed that the degree of soil Hg contamination varied depending on the sampling locations in the study region. The soils in JK and TR were categorized as having light-level Hg contamination, whereas those in SQ and BJ were at moderate-level Hg contamination. The potential ecological risk indicated that the soil suffered different degrees of Hg contamination (TR was at a medium level, BJ and JK were at a serious level, and SQ was at a high severe level of pollution). The dominant bacteria flora were Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi, whereas the dominant flora of fungi included Ascomycota, Basidiomycota, and Mortierellomycota. RDA analysis showed that pH, sucrase (SC), and catalase (CAT) activities were the key environmental factors of soil bacterial community structure. Soil pH, available nitrogen (AN), available potassium (AK), HCl-Hg, acid phosphatase (ACP), and urease (URE) activities were the key environmental factors that affected soil fungal community structure. Correlation network analysis indicated that pH, available phosphorus (AP), HCl-Hg, SC, ACP, and CAT were the key environmental factors affecting soil bacterial community structure, including Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, Firmicutes, Rokubacteria, and Planctomycetes. AK, pH, total nitrogen (TN), AP, AN, ACP, URE, and SC activities were the key environmental factors affecting soil fungal community structure, such as Ascomycota, Basidiomycota, Mortierellomycota, Glomeromycota, Chytridiomycota, Rozellomycota, Kickxellomycota, and Mucoromycota.

Influence of Temperature on Denitrification and Microbial Community Structure and Diversity: A Laboratory Study on Nitrate Removal from Groundwater

Temperature is an extremely important environmental condition in the application of microbial denitrification for nitrate removal from groundwater. Understanding the nitrate removal efficiency of groundwater and the diversity, composition, and structure of microbial communities under different temperature conditions is of great significance for effective mitigation of groundwater nitrate pollution. This study investigated the effects of temperature on denitrification at 15 °C, 25 °C, 40 °C, and 45 °C. Moreover, the characteristics of microbial community structure and diversity were analyzed by combining high-throughput sequencing and polymerase chain reaction methods in order to fully clarify the denitrification efficiency under different temperature conditions. According to laboratory batch experiments and the findings of previous research, glucose was set as the carbon source and changes in “three nitrogen” indicators of the four temperature systems were mainly tested to clarify the effectiveness of nitrate removal. The maximum removal rates of nitrate nitrogen at 15 °C, 25 °C, 40 °C, and 45 °C were 44.05%, 87.03%, 99.26%, and 92.79%, respectively. Therefore, the most efficient nitrate removal can be achieved at 40℃. The Chao abundance indexes in the denitrification systems at 15 °C, 25 °C, 40 °C, and 45 °C were 1873, 352, 466, and 640, respectively. Therefore, the highest species richness was observed at 15 °C, but there were only a few dominant bacteria species. The composition of the bacterial community and the most dominant phylum varied at different temperatures. Among them, Gammaproteobacteria in Proteobacteria phylum plays an important role in the degradation of nitrate nitrogen. The relative abundance of Gammaproteobacteria at 15 °C, 25 °C, 40 °C, and 45 °C were 25.32%, 66.56%, 72.83%, and 3.47%. Tolumonas belongs to Gammaproteobacteria. The relative abundance of Tolumonas at 15 °C, 25 °C, 40 °C, and 45 °C were 9.41%, 65.47%, 62.49%, and 0.03%, respectively. The results of this study show that different temperature conditions affect the diversity, composition, and structure of the microbial community, thereby affecting the efficiency of denitrification for nitrate removal from groundwater.

Seasonal Variations in the Characteristics of Microbial Community Structure and Diversity in Atmospheric Particulate Matter from Clean Days and Smoggy Days in Beijing.

Microorganisms are an important part of atmospheric particulate matter and are closely related to human health. In this paper, the variations in the characteristics of the chemical components and bacterial communities in PM10 and PM2.5 grouped according to season, pollution degree, particle size, and winter heating stage were studied. The influence of environmental factors on community structure was also analyzed. The results showed that seasonal variations were significant. NO3- contributed the most to the formation of particulate matter in spring and winter, while SO42- contributed the most in summer and autumn. The community structures in summer and autumn were similar, while the community structure in spring was significantly different. The dominant phyla were similar among seasons, but their proportions were different. The dominant genera were no-rank_c_Cyanobacteria, Acidovorax, Escherichia-Shigella and Sphingomonas in spring; Massilia, Bacillus, Acinetobacter, Rhodococcus, and Brevibacillus in summer and autumn; and Rhodococcus in winter. The atmospheric microorganisms in Beijing mainly came from soil, water, and plants. The few pathogens detected were mainly affected by the microbial source on the sampling day, regardless of pollution level. RDA (redundancy analysis) showed that the bacterial community was positively correlated with the concentration of particulate matter and that the wind speed in spring was positively correlated with NO3- levels, NH4+ levels, temperature, and relative humidity in summer and autumn, but there was no clear consistency among winter samples. This study comprehensively analyzed the variations in the characteristics of the airborne bacterial community in Beijing over one year and provided a reference for understanding the source, mechanism, and assessment of the health effects of different air qualities.

Distribution characteristics of microbial community structure in atmospheric particulates of the typical industrial city in Jiangsu province, China

ABSTRACT In this study, Xuzhou, a typical industrial city in the north of Jiangsu Province, was chosen to investigate the pollution level of atmospheric particulates. The proportion of fine particles (PM2.5) in PM10 is larger than that of coarse particles (about 58%). The physicochemical properties of PM2.5 were analyzed by SEM and EDS. DGGE was used to study the distribution characteristics of bacterial community structure on atmospheric particulates (TSP, PM2.5 and PM10) in different functional areas of Xuzhou city during the winter haze. It was found that the microbial populations of atmospheric particles were mainly divided into three groups: Proteobacteria, Bacteroidetes, and Pachytenella. The community structure of bacteria in fine particle size was more abundant than that in coarse particle size. When haze occurs, the concentration of all kinds of pathogens in fine particle size will increase. Therefore, it is necessary to focus on the monitoring and management of fine particles.

Characteristics of Microbial Community Structure at the Seafloor Surface of the Nankai Trough

Characteristics of Microbial Community Structure at the Seafloor Surface of the Nankai Trough

A comparative study of the effects of microbial agents and anaerobic sludge on microalgal biotransformation into organic fertilizer

The effects of Lactobacillus bulgaricus, Rhodopseudomonas palustris, Issatchenkia orientalis and anaerobic sludge on anaerobic digestion of microalgae to organic fertilizer were studied. High-throughput sequencing was used to analyze characteristics of microbial community structure during anaerobic digestion of microalgae using different inocula. Lactobacillales and Saccharomycetales were more likely to become dominant bacteria and eukaryotes. The relative abundance of Lactobacillales was 98.15%, 88.61% and 81.73% of total bacteria at the beginning, middle and end of the experiment, respectively. Meanwhile, the relative abundance of Saccharomycetales was 90.91%, 98.41% and 98.8% of eukaryotes at the beginning, middle and end of the experiment, respectively. At the end of digestion, the microcystin content in the reactor inoculated with Issatchenkia orientalis decreased to 0.71 μg/kg, which met drinking water standards. Rhodopseudomonas palustris did not become a dominant microorganism and had the most negative impact on the atmosphere. Volatile organic compounds were 11.92 mg/kg while the odor concentration reached 97,724 ou/m3. The organic matter content in reactors inoculated with specific groups of microbial agents, which was higher than the standard required for bio-organic fertilizer, occupying over 96% dry weight. In addition, the effective microorganism counts of Issatchenkia orientalis and Lactobacillus bulgaricus in fermentation products reached 1.8E+09 colony-forming units (cfu)/g and 1.6E+09 cfu/g, respectively, which are suitable values for microbial fertilizer.

北京市妫水河底泥微生物群落结构特征

北京市妫水河底泥微生物群落结构特征

Purification Efficiency and Microbial Characteristics of Four Biofilters Operated Under Different Conditions

To explore the effects of aeration, microbial acclimation period, and pool shape or flow pattern change on the purification efficiency of biofilters at the microbiological level, four biofilters with different working conditions, that is, MAVF, NAVF, NVF, and BHF, were studied. The first three are vertical-flow biofilters and the last one is a baffled-flow biofilter. The four filters filled with the same ceramsite were made of organic glass. The MAVF filter was connected with the BHF filter in series and was operated for one year prior to the trial. The NAVF and NVF filters are newly activated filters. The four filters that were used to treat domestic sewage were synchronously operated in batch mode in this study. The MAVF and NAVF filters were intermittently aerated in contrast to the other two. During the period of microbial acclimation of the newly activated filters, the purification efficiency of the four filters was continuously monitored and the microbial community structure characteristics were analyzed at the end of microbial acclimation. The results show that the purification efficiency of the three vertical-flow filters is significantly higher than that of the horizontal-flow one and aeration significantly enhances the purification efficiency. However, aeration has a weaker effect on the efficiency than the microbial maturity of the filter. An apparent accumulation of nitrates or nitrites in the four filters was not observed, indicating that the denitrification was rather thorough. The 16S rDNA high-throughput sequencing analysis shows that the diversity index of the four filters is BHF > MAVF > NAVF > NVF, indicating that the more mature the filter is, the higher is the diversity index. Most of the packing microorganisms are facultative heterotrophic bacteria and the most abundant are heterotrophic denitrifying bacteria. Heterotrophic nitrification occurs in the NVF and BHF filters and aeration promotes the enrichment of aerobic ammonium-oxidizing bacteria. Aerobic phosphorus-accumulating organisms were not detected in the four filters. Therefore, phosphorus was mainly removed via denitrifying phosphorus accumulation. Under the test conditions, the removal rate of total nitrogen was not high, mainly because nitrifying bacteria were not enriched in the filter or their abundance was insufficient. The latter resulted in the limited ammonium-oxidizing ability of the filter, thus affecting the removal of total nitrogen. The above-mentioned results show that the adjustment of different working conditions will affect the redox status and associated enrichment of functional bacteria inside the biofilter, which will ultimately affect the purification efficiency.

不同荒漠植物根际土壤微生物群落结构特征

不同荒漠植物根际土壤微生物群落结构特征

Effect of applying phosphorus bacteria fertilizer on bacterial diversity and phosphorus availability in reclaimed soil.

A located field experiment of applying phosphorus bacteria fertilizer for five years was carried out to study the effects of applying phosphorus bacteria fertilizer on the characteristics of microbial community structure in reclaimed soil. We studied the diversity of bacterial community using 16S rDNA gene sequencing and analyzed the relationship between bacterial community and Olsen-P, alkaline phosphatase. Seven treatments including control, chemical fertilizer, manure, manure and chemical fertilizer, chemical fertilizer and phosphorus bacteria, manure and phosphorus bacteria, and, manure,chemical fertilizer and phosphorus bacteria were conducted. The results showed that the relative abundance of Actinobacteria and Proteobacteria in reclaimed soil was the largest, which was 21.6％-32.2％ and 13.8％-28.9％, respectively. Operational taxonomic units (OTU) number and Chao1 index of the treatment of manure, chemical fertilizer and phosphorus bacteria fertilizer was 809 and 26190, which was the highest. Phosphorus bacteria fertilizer could improve the relative abundance of soil Actinomycetes and Proteobacteria and decrease that of soil Acidobacteria, Thermotogae and Nitrospira, and had stimulatory effect on Nocardioides and Flexibacter. The treatment of manure, chemical fertilizer and phosphorus bacteria fertilizer could improve the Olsen-P and alkaline phosphatase activities in reclaimed soil. Correlation coefficients between Proteobacteria and Olsen-P, alkaline phosphatase were the highest (0.900 and 0.955). To a certain extent, Proteobacteria could be used as the sensitivity index of soil phosphorus availability.

肉苁蓉寄主梭梭根际土壤微生物种类及群落结构特征

肉苁蓉寄主梭梭根际土壤微生物种类及群落结构特征