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1.
Isolation and phylogenetic analysis of cultivable manganese bacteria in sediments from the Arctic Ocean
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Isolation, molecular identification and phylogenetic analysis were carried out to investigate the biodiversity of manganese bacteria in sediments which were collected from the Arctic Ocean during the 2nd Chinese Arctic Scientific Expedition. 21 and 19 species of cultivable strains were isolated from sediments at Stations P11 and S11, respectively, according to their distinct morphological character on the screening plate of manganese medium. Molecular identification and phylogenetic analysis showed that the cultivable manganese bacteria from Station P11 were basically composed of γ-Proteobacteria (γ subgroup of the Proteobacteria branch of the domain Bacteria) and Actinobacteria, which accounted for 86% and 14%, respectively. The isolates of γ-Proteobacteria mainly included Psychrobacter, Shewanella, Acinetobacter and Marinobacter, of which Psychrobacter was the major genus, which accounted for 67% of the γ-Proteobacteria. The cultivable manganese bacteria from Station S11 included α-Proteobacteria, γ-Proteobacteria and Flavobacteria of Bacteroides. The γ-Proteobacteria mainly included Shewanella, Marinomonas and Alteromonas. The majority of α-Proteobacteria was Sphingomonas. The phylogenetic analysis indicated that bacteria from sediments at Stations P11 and S11 had different cultivable manganese microbial communities. All tested strains had higher resistance to Mn2+, of which Marinomonas sp. S11-S-4 had the highest resistant ability. 相似文献
2.
北极海洋沉积物中锰细菌的分离与系统发育 总被引:2,自引:0,他引:2
对中国第二次北极科学考察采集的北极海洋沉积物中的锰细菌进行了筛选、分离和系统发育分析。根据其在筛选平板上菌落的形态学特征,分别从站位P11和S11采集的沉积物中分离到了21株和19株锰细菌。系统发育分析表明,两个站位的锰细菌群落组成有着明显的差别。站位P11分离的可培养锰细菌主要由细菌域(Bacteria)中变形杆菌门的γ-变形杆菌纲(γ-Proteobacteria)和放线菌纲(Actinobacteria)组成,二者分别占86%和14%;γ-变形杆菌纲主要包括嗜冷杆菌属(Psychrobacter)、希瓦氏菌属(Shewanella)、假交替单胞菌属(Pseudoaheromonas)、不动杆菌属(Acinetobacter)、海杆菌属(Marinobacter),其中以嗜冷杆菌属为主,其比例可达67%。从站位S11分离到的可培养锰细菌主要包括细菌域中变形杆菌门的α-变形杆菌纲(α-Proteobacteria)和γ-变形杆菌纲以及拟杆菌门(Bacteroides)中的黄杆菌纲(Flavobaeteria);γ-变形杆菌纲主要包括希瓦氏菌属、海单胞菌属(Marinomonas)和交替单胞菌属(Aheromonas),α-变形杆菌纲主要为鞘氨醇单胞菌属(Sphingomonas)。实验菌株均对Mn^2+有着较强的抗性,其中以菌株Marinomonas sp.S11-S-4耐受性最高。 相似文献
3.
Factors affecting viable cell counts in groundwater or sediments were studied with samples from the Segeberg Forest test area in northern Germany. There was very little variation in results with the season (April, August, November) or depth of sampling; generally there were 103–104 aerobic cells per ml or g sediment. Long incubation times resulted in higher cell counts; groundwater samples required 4–5 weeks, and sediment extracts had to be cultured for 7 weeks. Total cell counts in sediment were 102–104 cell/g higher than viable cell counts of aerobes. This was explained partly by the additional presence of anaerobes and partly by the observation that some morphotypes may not have grown under our conditions. Viable cell counts were not influenced by cell extraction from the sediment with either Na-pyrophosphate or groundwater extracts. However, iron-precipitating or manganese-oxidizing bacteria were better extracted with sterile groundwater. The microflora of wells was more numerous than that of the free aquifer; consequently it was better to pump off all well water before aquifer water was sampled. The diameter of the well was also important; thinner tubes had higher cell counts than those with wider diameter. For sampling, wells should be at least 1 year old, since young wells contain higher numbers of microorganisms due to underground disturbances from the drilling. Turbid water samples could be clarified by filtration, but this reduced the viable counts by 1–2 orders of magnitude. Two different media inoculated with a sample dilution resulted in the same cell counts, but their microbial diversity was different. Storage of groundwater samples before processing resulted in up to 17-fold increases in cell counts and loss of diversity in the first 24 hours. Cell numbers decreased slowly during longer storage. 相似文献
4.
In Situ Exposure to Low Herbicide Concentrations Affects Microbial Population Composition and Catabolic Gene Frequency in an Aerobic Shallow Aquifer 总被引:2,自引:1,他引:1
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Julia R. de Lipthay Nina Tuxen Kaare Johnsen Lars H. Hansen Hans-Jrgen Albrechtsen Poul L. Bjerg Jens Aamand 《Applied microbiology》2003,69(1):461-467
The aim of this study was to evaluate how the in situ exposure of a Danish subsurface aquifer to phenoxy acid herbicides at low concentrations (<40 μg l−1) changes the microbial community composition. Sediment and groundwater samples were collected inside and outside the herbicide-exposed area and were analyzed for the presence of general microbial populations, Pseudomonas bacteria, and specific phenoxy acid degraders. Both culture-dependent and culture-independent methods were applied. The abundance of microbial phenoxy acid degraders (100 to 104 g−1 sediment) was determined by most probable number assays, and their presence was only detected in herbicide-exposed sediments. Similarly, PCR analysis showed that the 2,4-dichlorophenoxyacetic acid degradation pathway genes tfdA and tfdB (102 to 103 gene copies g−1 sediment) were only detected in sediments from contaminated areas of the aquifer. PCR-restriction fragment length polymorphism measurements demonstrated the presence of different populations of tfd genes, suggesting that the in situ herbicide degradation was caused by the activity of a heterogeneous population of phenoxy acid degraders. The number of Pseudomonas bacteria measured by either PCR or plating on selective agar media was higher in sediments subjected to high levels of phenoxy acid. Furthermore, high numbers of CFU compared to direct counting of 4′,6-diamidino-2-phenylindole-stained cells in the microscope suggested an increased culturability of the indigenous microbial communities from acclimated sediments. The findings of this study demonstrate that continuous exposure to low herbicide concentrations can markedly change the bacterial community composition of a subsurface aquifer. 相似文献
5.
Arsenic contamination in groundwater has been reported in the Jianghan Plain of China since 2005, yet little is known about the microbial communities involved in As mobilization in this area, especially the dissimilatory arsenate-reducing bacteria (DARB) communities. Here, we conducted a cultivation-independent investigation on core sediments collected from a region with arsenic-contaminated groundwater in the Jianghan Plain to reveal the total bacteria and DARB community structures. Highly diverse As-resistant bacteria communities were found from sediment samples via high-throughput sequencing of 16S rRNA genes. Notably, we identified 27 unique arrA gene (encoding the alpha subunit of dissimilatory arsenate reductase) phylotypes, none of which was related to any previously described arrA gene sequence. This suggests a novel and unique DARB community in the sediments of the Jianghan Plain and expands our knowledge about the distribution and diversity of this group of bacteria in natural environments. Moreover, RDA and CCA demonstrated that total bacterial communities and specific functional groups are controlled by different environmental factors. Specifically, sediment pH, NH4+, total nitrogen, total Fe, total organic carbon and total phosphorus were the key factors driving total bacterial community compositions, while As significantly shaped DARB community structures. This report is the first to describe DARB communities and their correlation with environmental factors in Jianghan Plain sediments, which could give us clues about the origin of the arsenic contamination of groundwater in this region. 相似文献
6.
Bacterial cell numbers obtained from 103 water and sediment samples from a Pleistocene sandy aquifer in the Lower Rhine region (Bocholt, FRG) were determinated on P-agar and by direct count. Below 5 m under the surface, colony-forming unit (cfu) numbers in water samples were less than 100/ml, and in many cases less than 50/ml. In sediment samples, they were 10- to 100-fold higher (102–104 cfu/g dry wt), but changing markedly between different depths. Direct cell counts yielded numbers two to three orders of magnitude higher.About 2,700 strains of bacteria from 60 samples were isolated randomly and characterized by morphological and physiological properties. Of all the isolates, 71.6% were gram-negative, and 52.2% were gram-negative straight rods. Water communities, with one exception, had low proportions of gram-positive bacteria (<11%), whereas in all but one of the sediment communities percentages of gram-positive isolates were three- to sevenfold higher (35–43%). Water and sediment communities, as well as communities from different sampling sites and communities from different depths of the same sampling site, differed in their qualitative and quantitative morphotype composition and physiological capabilities.The in vitro activities of strains within a single community were quite different, indicating that each community is composed of many diverse bacteria, several having extremely different capabilities. Thus, each community has its own specific activity pattern. Gram-positive bacteria showed on an average lower total activities than did gram-negative bacteria. Grampositive bacteria as well as gram-negative bacteria from sediment had higher values of in vitro activities than the corresponding groups isolated from water. Many water and sediment bacteria preferred the same substrates which were utilized at high rates. However, there were differences in the degradation of the various other substrates present, and each community showed preferences for particular substrates, which they degraded best.The results of cell morphology and physiology studies indicated that all eight characterized communities were very different from one another and very diversely structured. 相似文献
7.
Sedimentary arsenite-oxidizing and arsenate-reducing bacteria associated with high arsenic groundwater from Shanyin, Northwestern China 总被引:4,自引:0,他引:4
Aims: Shanyin County is one of the most severe endemic arsenism affected areas in China but micro-organisms that potentially release arsenic from sediments to groundwater have not been studied. Our aim was to identify bacteria with the potential to metabolize or transform arsenic in the sediments.
Methods and Results: Culture and nonculture-based molecular methods were performed to identify arsenite-oxidizing bacteria, arsenate-reducing bacteria and arsenite oxidase genes. Arsenite-oxidizing bacteria were identified only from the land surface to 7 m underground that were affiliated to α- and β-Proteobacteria. Arsenate-reducing bacteria were found in almost all the sediment samples with different depths (0–41 m) and mainly belong to γ-Proteobacteria. Several novel arsenite oxidase genes ( aoxBs ) were identified from the upper layers of the sediments (0–7 m) and were found to be specific for arsenite-oxidizing bacteria.
Conclusions: The distribution of arsenite-oxidizing bacteria in upper layers and arsenate-reducing bacteria in different depths of the sediments may impact the arsenic release into the nearby tubewell groundwater.
Significance and Impact of the Study: This study provides valuable sources of micro-organisms (and genes) that may contribute to groundwater arsenic abnormality and may be useful to clean arsenic contaminated groundwater. 相似文献
Methods and Results: Culture and nonculture-based molecular methods were performed to identify arsenite-oxidizing bacteria, arsenate-reducing bacteria and arsenite oxidase genes. Arsenite-oxidizing bacteria were identified only from the land surface to 7 m underground that were affiliated to α- and β-Proteobacteria. Arsenate-reducing bacteria were found in almost all the sediment samples with different depths (0–41 m) and mainly belong to γ-Proteobacteria. Several novel arsenite oxidase genes ( aoxBs ) were identified from the upper layers of the sediments (0–7 m) and were found to be specific for arsenite-oxidizing bacteria.
Conclusions: The distribution of arsenite-oxidizing bacteria in upper layers and arsenate-reducing bacteria in different depths of the sediments may impact the arsenic release into the nearby tubewell groundwater.
Significance and Impact of the Study: This study provides valuable sources of micro-organisms (and genes) that may contribute to groundwater arsenic abnormality and may be useful to clean arsenic contaminated groundwater. 相似文献
8.
Terry C. Hazen Luis Jiménez Geralyne López de Victoria Carl B. Fliermans 《Microbial ecology》1991,22(1):293-304
Samples of groundwater and the enclosing sediments were compared for densities of bacteria using direct (acridine orange direct
staining) and viable (growth on 1% PTYG medium) count methodology. Sediments to a depth of 550 m were collected from boreholes
at three sites on the Savannah River Site near Aiken, South Carolina, using techniques to insure a minimum of surface contamination.
Clusters of wells screened at discreet intervals were established at each site. Bacterial densities in sediment were higher,
by both direct and viable count, than in groundwater samples. Differences between direct and viable counts were much greater
for groundwater samples than for sediment samples. Densities of bacteria in sediment ranged from less than 1.00×106 bacteria/g dry weight (gdw) up to 5.01 ×108 bacteria/gdw for direct counts, while viable counts were less than 1.00×103 CFU/gdw to 4.07×107 CFU/gdw. Bacteria densities in groundwater were 1.00×103–6.31×104 bacteria/ml and 5.75–4.57×102 CFU/ml for direct and viable counts, respectively. Isolates from sediment were also found to assimilate a wider variety of
carbon compounds than groundwater bacteria. The data suggest that oligotrophic aquifer sediments have unique and dense bacterial
communities that are attached and not reflected in groundwater found in the strata. Effective in situ bioremediation of contaimination
in these aquifers may require sampling and characterization of sediment communities. 相似文献
9.
Kotaro Ise Yoshito Sasaki Yuki Amano Teruki Iwatsuki Isao Nanjo Takahiro Asano 《Geomicrobiology journal》2017,34(6):489-499
We investigated the change in bacterial community structure after drilling boreholes, 09-V250-M02 and 09-V250-M03, in the 250-m deep research gallery of the Horonobe Underground Research Laboratory. In the 09-V250-M02 borehole, ?-Proteobacteria were predominantly detected in the clone library analyses of the groundwater samples conducted immediately after drilling. All the ?-Proteobacteria clones were closely related to Arcobacter spp., which are known to be sulfide-oxidizing chemoautotrophic bacteria. After 4 years, the microbial structure drastically changed, and most detected operational taxonomic units were uncultured species such as candidate division OP9 and Chloroflexi relatives, which are frequently detected in deep sea sediments. The results indicated that the microbial community structure was drastically affected by borehole drilling and was concomitant with oxidation perturbation. However, these disturbed microbial communities changed within a few years to a microbial community composed of uncultivated species such as OP9 and Chloroflexi. 相似文献
10.
As a collaborative effort to characterize a pilot test site for managed aquifer recharge (MAR), vertical and horizontal distributions of microbial communities in the river bank subsurface were investigated to assess the ecological effects after the operation of the MAR using the river water adjacent to the site. Along with a geochemical analysis, barcoded pyrosequencing was performed using the genomic DNAs extracted from the subsurface groundwater/sediment samples retrieved from three multilevel wells among the installed cluster of 14 boreholes. A total of 9 samples from 3 depths (10, 15–25, and 33 m below the ground surface) of each borehole showed higher bacterial abundance and diversity in the shallow (10 m) depths than in the deep (33 m) groundwater. In addition, there was a slight separation of the microbial communities between the depths based on the nonmetric multidimensional scaling analysis of the Yue and Clayton distance and the distance-weighted UniFrac analysis. The phylum Proteobacteria was dominant in all the samples at the sequence abundance of 64.0–97.8% with the total operational taxonomic units of 3375 at the species level, while among the total 288 genera, the genus Pseudomonas and an unclassified genus from Betaproteobacteria were the most abundant across the samples. The community separation between the shallow and the deep groundwater seemed to be correlated with depth differences, supported by differences in the dissolved oxygen (DO) concentration and oxidation-reduction potential (ORP). In the study site, unusually high values of electrical conductivity (EC) were found in the deep groundwater, but those values were unlikely to contribute to the community separation between the shallow and deep groundwater, unlike the DO and ORP values, which were found to influence the community differences. 相似文献
11.
Distribution and Composition of Microbial Populations in a Landfill Leachate Contaminated Aquifer (Grindsted, Denmark) 总被引:3,自引:0,他引:3
Ludvigsen L Albrechtsen H Ringelberg DB Ekelund F Christensen TH 《Microbial ecology》1999,37(3):197-207
Abstract
To investigate whether landfill leachates affected the microbial biomass and/or community composition of the extant microbiota,
37 samples were collected along a 305-m transect of a shallow landfill-leachate polluted aquifer. The samples were analyzed
for total numbers of bacteria by use of the acridine orange direct count method (AODC). Numbers of dominant, specific groups
of bacteria and total numbers of protozoa were measured by use of the most probable number method (MPN). Viable biomass estimates
were obtained from measures of ATP and ester-linked phospholipid fatty acid (PLFA) concentrations. The estimated numbers of
total bacteria by direct counts were relatively constant throughout the aquifer, ranging from a low of 4.8 × 106 cells/g dry weight (dw) to a high of 5.3 × 107 cells/g dw. Viable biomass estimates based on PLFA concentrations were one to three orders of magnitude lower with the greatest
concentrations (up to 4 × 105 cells/g dw) occurring at the border of the landfill and in samples collected from thin lenses of clay and silt with sand
streaks. Cell number estimates based on ATP concentrations were also found to be lower than the direct count measurements
(<2.2 × 106 cells/g dw), and with the greatest concentrations close to the landfill. Methanogens (Archaea) and reducers of sulfate, iron,
manganese, and nitrate were all observed in the aquifer. Methanogens were found to be restricted to the most polluted and
reduced part of the aquifer at a maximum cell number of 5.4 × 104 cells/g dw. Populations of sulfate reducers decreased with an increase in horizontal distance from the landfill ranging from
a high of 9.0 × 103 cells/g dw to a low of 6 cells/g dw. Iron, manganese, and nitrate reducers were detected throughout the leachate plume all
at maximum cell numbers of 106 cells/g dw. Changes in PLFA profiles indicated that a shift in microbial community composition occurred with increasing horizontal
distance from the landfill. The types and patterns of lipid biomarkers suggested that increased proportions of sulfate- and
iron-reducing bacteria as well as certain microeukaryotes existed at the border of the landfill. The presence of these lipid
biomarkers correlated with the MPN results. There was, however, no significant correlation between the abundances of the specific
PLFA biomarkers and quantitative measurements of redox processes. The application of AODC, MPN, PLFA, and ATP analyses in
the characterization of the extant microbiota within the Grindsted aquifer revealed that as distance increased from the leachate
source, viable biomass decreased and community composition shifted. These results led to the conclusion that the landfill
leachate induced an increase in microbial cell numbers by altering the subsurface aquifer so that it was conducive to the
growth of methanogens and of iron-and sulfate-reducing bacteria and fungi.
Received: 11 June 1998; Accepted: 10 December 1998 相似文献
12.
Seasonal patterns of groundwater and sediment microbial communities were explored in a hydrologically dynamic alpine oligotrophic porous aquifer, characterized by pronounced groundwater table fluctuations. Rising of the groundwater level in consequence of snow melting water recharge was accompanied by a dramatic drop of bacterial Shannon diversity in groundwater from H' = 3.22 ± 0.28 in autumn and winter to H' = 1.31 ± 0.35 in spring and summer, evaluated based on T-RFLP community fingerprinting. Elevated numbers of bacteria in groundwater in autumn followed nutrient inputs via recharge from summer rains and correlated well with highest concentrations of assimilable organic carbon. Sterile sediments incubated to groundwater in monitoring wells were readily colonized reaching maximum cell densities within 2 months, followed by a consecutive but delayed increase and leveling-off of bacterial diversity. After 1 year of incubation, the initially sterile sediments exhibited a similar number of bacteria and Shannon diversity when compared to vital sediment from a nearby river incubated in parallel. The river bed sediment microbial communities hardly changed in composition, diversity, and cell numbers during 1 year of exposure to groundwater. Summing up, the seasonal hydrological dynamics were found to induce considerable dynamics of microbial communities suspended in groundwater, while sediment communities seem unaffected and stable in terms of biomass and diversity. 相似文献
13.
Carbon Source Utilization Profiles for Microbial Communities from Hydrologically Distinct Zones in a Basalt Aquifer 总被引:1,自引:0,他引:1
Abstract
The Eastern Snake River Plain aquifer has hydrologically distinct zones in basalt flow units and interbedded sediments. The
zones that differ markedly in physical features (e.g., porosity and permeability) have similar groundwater chemistries. The
primary objective of this study was to determine whether intervals within the aquifer that contrast on the basis of permeability
have distinct communities of unattached microorganisms based on functional attributes. Aquifer sampling was conducted using
a submersible pump to obtain whole-well (w) samples, and a straddle-packer pump (SPP) to obtain samples from specific aquifer
intervals that were vertically distributed in the open borehole. The SPP intervals ranged from 4.6 to 6.1 m in length and
were located from 142 to 198 m below land surface. A community-level physiological profile (CLPP) was used to determine functional
characteristics of the microbial community in the groundwater samples based on the community response to 95 sole organic carbon
sources. Surface soil samples at the site were analyzed in a similar manner for comparison. The total bacterial population
in the groundwater samples was determined using acridine orange direct counts. Principal components analysis (PCA) of the
CLPP dataset distinguished between surface soil and aquifer microbial communities. Soils scored low in the respiration of
polymers, esters, and amines and high in bromosuccinate, when compared to aquifer samples. The W samples were distinct from
SPP samples. The 180- to 198-m interval, with the lowest hydraulic conductivity of all intervals, yielded samples that grouped
together by PCA and cluster analysis. Direct counts varied between 104 and 105 cells ml−1, and showed no relationship to the depth of the sample or to the hydraulic conductivity of the sample interval. Differences
between microbial communities based on respired carbon compounds were discerned in separate, hydrologically distinct intervals
within the borehole, although these differences were slight. Differences among aquifer intervals were less apparent than differences
between surface soils and groundwater, and may be related to variations in hydrologic properties over the intervals sampled.
The results suggest that free-living microbial communities in basalt aquifers, as characterized by CLPP are relatively unaffected
by wide ranges in hydraulic conductivity when other abiotic factors are essentially equal.
Received: 14 December 1995; Revised: 12 April 1996 相似文献
14.
Joshi AA Kanekar PP Kelkar AS Shouche YS Vani AA Borgave SB Sarnaik SS 《Microbial ecology》2008,55(2):163-172
Aerobic, alkaliphilic bacteria were isolated and characterized from water and sediment samples collected in the winter season,
January 2002 from alkaline Lonar lake, India, having pH 10.5. The total number of microorganisms in the sediment and water
samples was found to be 102–106 cfu g−1 and 102–104 cfu ml−1, respectively. One hundred and ninety-six strains were isolated using different enrichment media. To study the bacterial
diversity of Lonar lake and to select the bacterial strains for further characterization, screening was done on the basis
of pH and salt tolerance of the isolates. Sixty-four isolates were subjected to phenotypic, biochemical characterization and
16S rRNA sequencing. Out of 64, 31 bacterial isolates were selected on the basis of their enzyme profile and further subjected
to phylogenetic analysis. Phylogenetic analysis indicated that most of the Lonar lake isolates were related to the phylum
Firmicutes, containing Low G+C, Gram-positive bacteria, with different genera: Bacillus, Paenibacillus, Alkalibacillus, Exiguobacterium, Planococcus, Enterococcus and Vagococcus. Seven strains constituted a Gram-negative bacterial group, with different genera: Halomonas, Stenotrophomonas and Providencia affiliated to γ-Proteobacteria, Alcaligenes to β-Proteobacteria and Paracoccus to α-Proteobacteria. Only five isolates were High G+C, Gram-positive bacteria associated with phylum Actinobacteria, with
various genera: Cellulosimicrobium, Dietzia, Arthrobacter and Micrococcus. Despite the alkaline pH of the Lonar lake, most of the strains were alkalitolerant and only two strains were obligate alkaliphilic.
Most of the isolates produced biotechnologically important enzymes at alkaline pH, while only two isolates (ARI 351 and ARI
341) showed the presence of polyhydroxyalkcanoate (PHA) and exopolysaccharide (EPS), respectively. 相似文献
15.
Microbial community structure and biomass estimates of a methanogenic Antarctic Lake ecosystem as determined by phospholipid analyses 总被引:3,自引:0,他引:3
Phospholipid analyses were performed on water column particulate and sediment samples from Ace Lake, a meromictic lake in the Vestfold Hills, Antarctica, to estimate the viable microbial biomass and community structure in the lake. In the water column, methanogenic bacterial phospholipids were present below 17 m in depth at concentrations which converted to a biomass of between 1 and 7×108 cells/liter. Methanogenic biomass in the sediment ranged from 17.7×109 cells/g dry weight of sediment at the surface to 0.1×109 cells/g dry weight at 2 m in depth. This relatively high methanogenic biomass implies that current microbial degradation of organic carbon in Ace Lake sediments may occur at extremely slow rates. Total microbial biomass increased from 4.4×108 cells/ liter at 2 m in depth to 19.4×108 cells/liter at 23 m, near the bottom of the water column. Total nonarchaebacterial biomass decreased from 4.2 ×109 cells/g dry weight in the surface sediment (1/4 the biomass of methanogens) to 0.06×108 cells/g dry weight at 2 m in depth in the sediment. Phospholipid fatty acid profiles showed that microeukaryotes were the major microbial group present in the oxylimnion of the lake, while bacteria dominated the lower, anoxic zone. Sulfate-reducing bacteria (SRB) comprised 25% of the microbial population at 23 m in depth in the water column particulates and were present in the surface sediment but to a lesser extent. Biomass estimates and community structure of the Ace Lake eco-system are discussed in relation to previously measured metabolic rates for this and other antarctic and temperate ecosystems. This is the first instance, to our knowledge, in which the viable biomass of methanogenic and SRB have been estimated for an antarctic microbial community. 相似文献
16.
Microbiological and Geochemical Heterogeneity in an In Situ Uranium Bioremediation Field Site 总被引:8,自引:4,他引:4
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Helen A. Vrionis Robert T. Anderson Irene Ortiz-Bernad Kathleen R. O''Neill Charles T. Resch Aaron D. Peacock Richard Dayvault David C. White Philip E. Long Derek R. Lovley 《Applied microbiology》2005,71(10):6308-6318
The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation. 相似文献
17.
Albert Brugger Bettina Reitner Ingrid Kolar Nadia Quéric & Gerhard J. Herndl 《Freshwater Biology》2001,46(8):997-1016
1. Interstitial bacterial abundance, production and ectoenzyme activity were investigated over an annual cycle in an Austrian river when infiltration of oligotrophic river water into a river-bank was artificially enhanced. These microbial parameters were related to porewater chemistry and the concentration of particulate (POC) and dissolved organic carbon (DOC).
2. Porewater chemistry reflected the hydrodynamic mixing of infiltrating river water with riparian groundwater. Seasonal fluctuations in the microbial parameters resulted mainly from changes in temperature and organic matter supply. Seasonal change in porewater chemistry in the river-bank was detectable laterally only within the first metre of the sediment and decreased rapidly with increasing distance from the sediment–water interface.
3. The DOC concentration decreased only slightly during lateral transport through the aquifer, while total organic carbon (TOC) concentration as well as abundance and activity of interstitial bacteria were reduced by up to one order of magnitude within the top metre of the sediment. Retention of incoming particulate matter structured the lateral distribution pattern of TOC concentration. The POC and not the DOC pool was the main source of carbon for interstitial bacteria and, therefore, the quality of POC determines the distribution of microbial metabolism within the riparian zone. 相似文献
2. Porewater chemistry reflected the hydrodynamic mixing of infiltrating river water with riparian groundwater. Seasonal fluctuations in the microbial parameters resulted mainly from changes in temperature and organic matter supply. Seasonal change in porewater chemistry in the river-bank was detectable laterally only within the first metre of the sediment and decreased rapidly with increasing distance from the sediment–water interface.
3. The DOC concentration decreased only slightly during lateral transport through the aquifer, while total organic carbon (TOC) concentration as well as abundance and activity of interstitial bacteria were reduced by up to one order of magnitude within the top metre of the sediment. Retention of incoming particulate matter structured the lateral distribution pattern of TOC concentration. The POC and not the DOC pool was the main source of carbon for interstitial bacteria and, therefore, the quality of POC determines the distribution of microbial metabolism within the riparian zone. 相似文献
18.
Microbial populations in 16 groundwater samples from six Fennoscandian Shield sites in Finland and Sweden were investigated. The average total cell number was 3.7×105 cells ml−1, and there was no change in the mean of the total cell numbers to a depth of 1390 m. Culture media were designed based on the chemical composition of each groundwater sample and used successfully to culture anaerobic microorganisms from all samples between 65 and 1350 m depth. Between 0.0084 and 14.8% of total cells were cultured from groundwater samples. Sulfate-reducing bacteria, iron-reducing bacteria and heterotrophic acetogenic bacteria were cultured from groundwater sampled at 65–686 m depth in geographically distant sites. Different microbial populations were cultured from deeper, older and more saline groundwater from 863 to 1350 m depth. Principal component analysis of groundwater chemistry data showed that sulfate- and iron-reducing bacteria were not detected in the most saline groundwater. Iron-reducing bacteria and acetogens were cultured from deep groundwater that contained 0.35–3.5 mM sulfate, while methanogens and acetogens were cultured from deep sulfate-depleted groundwater. In one borehole from which autotrophic methanogens were cultured, dissolved inorganic carbon was enriched in 13C compared to other Fennoscandian Shield groundwater samples, suggesting that autotrophs were active. It can be concluded that a diverse microbial community is present from the surface to over 1300 m depth in the Fennoscandian Shield. 相似文献
19.
Röling WF van Breukelen BM Braster M Goeltom MT Groen J van Verseveld HW 《Microbial ecology》2000,40(3):177-188
Abstract
Databases containing information regarding presence and activity of microbial communities will be very useful for determination
of the potential for intrinsic bioremediation in landfill leachate polluted aquifers. Simple analyses such as community-level
physiological profiling (CLPP) and denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments yield large sets of
data for inclusion into such databases. In this study we describe the development of a method for anaerobic CLPP, using commercially
available Biolog plates. Incubation at the in situ temperature of the aquifer (10°C) for 28 days was optimal for obtaining a specific, reproducible physiological profile. Anaerobic
incubation was essential for profiling anaerobic communities. The anaerobic cultivation-dependent CLPP method and cultivation-independent
DGGE were applied to groundwater and sediment samples from the aquifer near the Coupépolder landfill in The Netherlands. A
combination of computer-assisted CLPP and DGGE analysis of both groundwater and sediment samples yielded the best separating
power for characterizing microbial communities in the aquifer. Communities in groundwater were significantly different from
those in the corresponding sediment. Microbial communities present in subsamples from sediment cores usually were similar
for the various sampling locations. Variation was observed for the heterogeneous sediment beneath the landfill. Both anaerobic
CLPP and DGGE analysis clearly separated microbial communities from the polluted aquifer underneath the landfill from those
in the less or not polluted aquifer downstream and upstream of the landfill.
Received: 3 January 2000; Accepted: 21 March 2000; Online Publication: 28 August 2000 相似文献
20.
Wei Zhang Gaosen Zhang Guangxiu Liu Zhongqin Li Tuo Chen Lizhe An 《Geomicrobiology journal》2013,30(5):459-469
The bacterial distribution, and its relationship with climate and environment factors were investigated in the snowcover at Tianshan Number 1 Glacier. The results showed that psychrotrophs were the preponderant bacteria in pit samples, though they were not the dominant species in the new fallen snow. The quantity and diversity of the cultivable bacteria decreased with the passage of time, indicating that the bacterial community acclimatized to low temperature by changing its structure. During this time, the peak number of the cultivable bacteria was associated with dirt layers, indicating that the bacterial input came with dust. Concurrently, the quantity and diversity of the cultivable bacteria showed a trend of variation similar to that shown by the δ18O values and the soluble ion concentrations, indicating that the bacterial distribution was related to both temperature and the amount of dust transported onto the glacier. Phylogentic analyses of 16S rRNA indicated that all the isolates fell into six categories: α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group bacteria, high G+C gram-positive bacteria, and low G+C gram-positive bacteria. In the snow pit, the abundance of the CFB group bacteria (mainly of the genus Flavobacterium) decreased from 55.5% to 1.49% with age, and fluctuated similar to the ion concentrations and the δ18O value. Meanwhile the α-Proteobacteria (mainly of the genus Brevundimonas) increased from 0.9% to 88.1%, indicating that Brevundimonas was the dominant psychrotroph in the study area, whose abundance varied inversely compared to the above-mentioned chemical properties. All the results suggest that bacterial abundance and diversity vary with climate and the physical chemical microenvironment. The pattern of bacterial distribution could be a biological index for the record of climate and environment change in the Tianshan Number 1 Glacier. 相似文献