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1.
Morphological and cultural comparison of microorganisms in surface soil and subsurface sediments at a pristine study site in Oklahoma 总被引:1,自引:0,他引:1
Surface-soil and subsurface microfloras at the site of a shallow aquifer in Oklahoma were examined and compared with respect to (1) total and viable cell numbers, (2) colony and cell types that grew on various plating media, (3) cell morphologies seen in flotation films stripped from sample particles, and (4) cellular ultrastructure. Appreciable numbers of microbial cells were present in the subsurface (total counts: 106–107 cellsg–1; viable counts up to 106 cells · g–1), but the subsurface microflora was considerably less populous than that of the surface soil (total counts: 109 cells·g–1; viable counts: 107–108 cells · g–1). The subsurface microflora (especially that of the saturated zone) also appeared to be much less diverse, containing fewer microbial types that would grow on enumeration plates (on nutrient-rich media, 3–4 colony types versus 19–22 for the surface soil) and fewer cell types that could be distinguished by direct microscopy (3–4 types versus 17 for the surface soil). The specific types of microorganisms that were numerically predominant in the aquifer sediments were entirely different from those that were predominant in the surface soil. Moreover, the predominant types varied from one depth to another within the saturated zone. The potential metabolic capability of the subsurface microflora, as indicated by its readiness to grow rapidly on nutrient-rich media, also varied with depth. 相似文献
2.
Sediment core samples were obtained at a groundwater study site in Oklahoma in January and June 1985. Most-probable-number estimates showed that protozoan numbers declined steeply with depth in subsoil. Flagellates and amoebae dominated the protozoan population, which declined to a most probable number of 28 . g (dry weight) in a clay loam layer at the bottom of the unsaturated zone. Samples from a texturally variable interface zone between 3 and 4 m down also were variable in their content of protozoa. Four contiguous clay loam samples in a single core from this zone contained variable numbers of amoebae ranging from 0.2 to 44 . g (dry weight). However, a sandy clay loam layer at the bottom of the core contained a mixture of flagellates and amoebae with a combined population density of 67 . g (dry weight). A slow-growing filose amoeba was isolated from interface zone samples and was tentatively classified in a new family in the order Aconchulinida. Protozoa were not detected in the saturated zone except in a very permeable gravelly, loamy sand layer at a depth of approximately 7.5 m. Low numbers (4 to 6 . g [dry weight]) of surface-type flagellates and amoebae, as well as the filose amoeba seen in the interface zone, were observed in this layer. Acid-treated and untreated samples contained equivalent numbers of protozoa, showing that the majority of protozoa in the layer at 7.5 m and the interface zone samples were encysted. Increased numbers of bacteria also were found in the layer at 7.5 m, indicating that it was biologically more active than other saturated-zone layers. Cyanobacteria grew in illuminated samples from this layer, suggesting that it may be connected hydrologically to a nearby river. 相似文献
3.
Subsurface sediment samples were collected from 4 to 31 m below landsurface in glacio-fluvial sediments from the Quaternary period. The samples were described in terms of pH, electrical conductivity, chloride concentration, organic matter content, and grain size distribution. Viable counts of bacteria varied from 0.5 to 1,203 x 103 colony forming units/g dry weight (gdw); total numbers of bacteria acridine orange direct counts (AODC) varied from 1.7 to 147 × 107 cells/gdw; growth rates (incorporation of [3H]-thymidine) varied from 1.4 to 60.7 × 104 cells/(gdw · day); and rate constants for mineralization of 14C-labelled compounds varied from 0.2 to 2.3 × 10–3 ml/(dpm · day) for acetate, and from 0 to 2.0 × 10–3 ml/(dpm · day) for phenol. Sediment texture influenced the total number of bacteria and potential for mineralization; with increasing content of clay and silt and decreasing content of sand, AODC increased and the mineralization rate declined. Intrinsic permeability calculated from grain size correlated positively with mineralization rate for acetate. Statistical correlation analysis showed high correlations between some of the abiotic parameters, but it was not possible to point out a single abiotic parameter that could explain the variation of size and activity of the microbial population. The microbial data obtained in these geologically young sediments were compared to literature data from older sediments, and this comparison showed that age and type of geological formation might be important for the size and activity of the microbial populations.Offprint requests to: H.-J. Albrechtsen. 相似文献
4.
Dissimilatory nitrate reduction (denitrification) in subsurface sediments by indigenous microflora was investigated in samples obtained over a range of depths from 0 to 289 m. Denitrifying activity in sediment samples retrieved from similar stratigraphic horizons at four different sites was determined by measuring the accumulation of N2O using the acetylene blockage technique. Denitrification was detected in unamended samples which received only prereduced deionized water at almost all depths in all sediments sampled. The surface sediments showed the highest denitrification activity. In the deeper sediments, denitrifying activity was much higher in saturated sandy samples and lower or absent in drier clay samples. Addition of nitrate enhanced denitrification activity in all samples from below the water table down to the maximum depth sampled (289 m), while addition of a carbon (succinate) source in general had no stimulatory effect. These results show that denitrifying microorganisms were present in all of the deep subsurface sediments tested in this study. Furthermore, these results suggest that adequate supplies of metabolizable organic carbon were available to support denitrifying activity. However, denitrification may be limited by inadequate supplies of nitrate in the sediments. 相似文献
5.
Phylogenetic analysis of the bacterial communities in Lake Baikal bottom sediments in the region of subsurface methane hydrate depositions has been carried out using data on 16S rRNA sequences. The composition of these microbial communities is shown to be different in different horizons. Methanotrophic bacteria are found in the surface layer (0-5 cm), and uncultured bacteria constitute a great portion of this population. In deeper sediment layers (92-96 cm), achange in the microbial community occurs; specifically, a decreased homology with the known sequences is observed. The new sequences form separate clusters on a phylogenetic tree, indicating the possibly endemic nature of the bacteria revealed. Organisms related to the genus Pseudomonas constitute the main portion of the population. An archaea-related sequence was found in a horizon containing gas hydrate crystals (100-128 cm). Uncultured bacteria remain predominant. 相似文献
6.
Distribution of aerobic bacteria,protozoa, algae,and fungi in deep subsurface sediments 总被引:1,自引:0,他引:1
The distribution of microorganisms in deep subsurface profiles was determined at three sites at the Savannah River Plant, Aiken, South Carolina. Acridine orange direct counts (AODC) of bacteria were highest in surface soil samples and declined to the 106 to 107 per gram range in the subsurface, but then did not decline further with depth. In the subsurface, AODC values varied from layer to layer, the highest being found in samples from sandy aquifer formations and the lowest in clayey interbed layers. Sandy aquifer sediments also contained the highest numbers of viable bacteria as determined by aerobic spread plate counts (CFU) on a dilute heterotrophic medium. In some of these samples bacterial CFU values approached 100% of the AODC values. Viable protozoa (amoebae and flagellates, but no ciliates) were found in samples with high bacterial CFU values. A variety of green algae, phytoflagellates, diatoms, and a few cyanobacteria were found at low population densities in samples from two of the three boreholes. Low numbers of fungi were evenly distributed throughout the profiles at all three sites. Microbial population density estimates correlated positively with sand content and pore‐water pH, and negatively with clay content and pore‐water metal concentration. A large diversity of prokaryotic and eukaryotic microorganisms was found in samples with high population densities. A survey of bacterial strains isolated from subsurface samples revealed associations of gram‐positive bacteria with high clay sediments and gram‐negative bacteria with sandy sediments. The ability to deposit lipophilic storage material (presumably poly‐ß‐hydroxybutyrate) was found in a high proportion of isolates from sandy sediments, but only rarely in isolates from high clay sediments. 相似文献
7.
Over 80 years of direct discharge of industrial effluents into the Mahoning River, located in northeastern Ohio, USA, has led to the accumulation of a wide variety of pollutants within its sediments. This study examined the physical and chemical parameters, including lipophilic pollutants, affecting microbial activity and biomass in subsurface (10-40 cm horizon) sediments. Microbial biomass was higher in anthropogenically contaminated sediments, and step-wise linear regression showed that approximately 82% of the variation in microbial biomass could be explained by total hexane extractable hydrocarbons, sediment particle size, and water content. There was no correlation between microbial activity and biomass. Independent variables influencing anaerobic activity were temperature and water holding capacity. The results of this study indicate that freshwater, sedimentary anaerobic microbial communities respond to a range of environmental parameters, many of which influence subsurface river sediments, and that lipophilic pollutants, when present, can cause increases in total microbial biomass. 相似文献
8.
9.
Stream- and soilwater at the 18.7 ha pristineIngabekken catchment, on gneiss bedrock at Høylandet,have been studied for three years, including intensiveepisode studies in spring and autumn. The site mainlyconsists of blanket bogs which are typical for thesemarine west coast climates. Water drains through theblanket peats by means of two major flowpaths. Eachflowpath contributes to the stream with a distinctchemical fingerprint rendered by the soil/soil waterinteractions along the flowpath, i.e. they may beregarded as end-members. The soil water from the upperpeat layers is the end-member representative ofstormflow discharge whereas baseflow originates mainlyfrom seepage of the other end-member, which is themineral soil water from beneath the peat. ThepHBaCl2 of the soils that control the runoffchemistry during highflow conditions was as low as2.6, allowing for a substantial pH drop in streamwaterin the case of a seasalt episode. pH in the streamvaried from more than 7 at baseflow to 5 or slightlybelow at stormflow. The lowest pH (4.8) was observedduring early snowmelt due to release of meltwaterhighly enriched in seasalts. The fraction ofexchangeable aluminum (AlS) was much higher in thesurface layers of the lower reaches of the catchmentthan close to the water divide. This suggests atransport of Al, much like podzolisation, thoughdownslope by a lateral flowpath. A Principal ComponentAnalysis on the stream water chemical data shows theimportance of water flowpaths in addition to dilutionor ionic strength and antecedent conditions as afactor in determining the water quality. On the planeof the two major principal components the base cations(Ca2+, Mg2+, Na+, K+) werenegatively related to [H+], and the total organiccarbon (TOC) was negatively related to strong acidanions (Cl-, SO4
2-, NO3
-).These relationships between the parameter loadingsalong the two main principal components remainedindifferent to the effects of both dilution andflowpaths.Under the present conditions of low acid deposition,this sensitive system is effectively buffered by itsweak acids and all released Al is complexed by naturalorganic acids. Similar boggy areas located in regionswith heavy anthropogenic acid deposition may not beable to neutralize the mineral acids. A shallow waterflowpath and a high H+ saturation of the ionexchanger in the soils controlling the highflowchemistry may lead to discharge episodes where strongmineral acids are allowed to pass through the systemreleasing elevated levels of toxic aluminum in thestream. 相似文献
10.
Methanogenesis, sulfate reduction, and rates of carbon mineralization were determined for samples derived at different depths from four cores drilled at the Savannah River Plant, Aiken South Carolina. Three‐gram subsamples of the sediments were dispensed to 10‐mL serum bottles under 5% H2/95% N2 and amended with 0.5 mL degassed distilled water with or without the following solutes: formate plus acetate, bicarbonate, lactate, and radiolabeled sulfate, glucose, and Índole. After incubating 1 to 5 days, the sediments were assayed for methane, H2, 35S, and I4CO2. No methanogenesis was detected at any depth in any core and sulfate was rarely reduced. Evolution of 14CO2 from glucose and indole was detected in sediments as deep as 262 and 259 m, respectively. At some depths the 14CO2 evolution rate was comparable to that of surface soils; however, at other depths no 14CO2 evolution could be detected. Injection of sterile air into anaerobic incubations increased rates of carbon mineralization at all depths that had demonstrated anaerobic activity and stimulated mineralization activity in sediments that were inactive anaerobically, suggesting a predominance of aerobic metabolism. Increasing the concentration of added glucose and indole often increased the resulting rates of 14CO2 evolved from these substrates. Our data indicate that both aerobic and anaerobic microorganisms are present and metabolically active in samples from deep subsurface environments. 相似文献
11.
Takeda K Nishiyama Y Yoda K Watanabe T Nimura-Matsune K Mura K Tokue C Katoh T Kawasaki S Niimura Y 《Bioscience, biotechnology, and biochemistry》2004,68(1):20-27
Peroxiredoxin (Prx) constitutes a large family of enzymes found in microorganisms, animals, and plants, but the detection of the activities of Prx-linked hydroperoxide reductases (peroxiredoxin reductases) in cell extracts, and the purification based on peroxide reductase activity, have only been done in bacteria and Trypanosomatidae. A peroxiredoxin reductase (NADH oxidase) from a bacterium, Amphibacillus, displayed only poor activities in the presence of purified Prx from Saccharomyces or Synechocystis, while it is highly active in the presence of bacterial Prx. These results suggested that an enzyme system different from that in bacteria might exist for the reduction of Prx in yeast and cyanobacteria. Prx-linked hydroperoxide reductase activities were detected in cell extracts of Saccharomyces, Synechocystis, and Chlorella, and the enzyme activities of Saccharomyces and Chlorella were induced under vigorously aerated culture conditions and intensive light exposure conditions, respectively. Partial purification of Prx-linked peroxidase from the induced yeast cells indicated that the Prx-linked peroxidase system consists of two protein components, namely, thioredoxin and thioredoxin reductase. This finding is consistent with the previous report on its purification based on its protein protection activity against oxidation [Chae et al., J. Biol. Chem., 269, 27670-27678 (1994)]. In this study we have confirmed that Prx-linked peroxidase activity are widely distributed, not only in bacteria species and Trypanosomatidae, but also in yeast and photosynthetic microorganisms, and showed reconstitution of the activity from partially purified interspecies components. 相似文献
12.
Distribution of microorganisms in the subsurface of the manus basin hydrothermal vent field in Papua New Guinea 总被引:2,自引:0,他引:2
The distribution of microorganisms in the subsurfaces of hydrothermal vents was investigated by using subvent rock core samples. Microbial cells and ATP were detected from cores taken at depths of less than 99.4 and 44.8 m below the seafloor (mbsf), respectively. Cores from various depths were incubated anaerobically with a heterotrophic medium. Growth at 60 and 90 degrees C was ascribed to a Geobacillus sp. in the 448.6- to 99.4-mbsf cores and a Deinococcus sp. in the 64.8- to 128.9-mbsf cores, respectively, based on the 16S ribosomal DNA analysis. 相似文献
13.
David L. Balkwill 《Geomicrobiology journal》2013,30(1-2):33-52
The aerobic, chemoheterotrophic bacteria indigenous to deep aquifers and other subsurface sediments (depths to 265 m) at a site in South Carolina were characterized by direct microscopy, enumeration of viable cells, analysis of colony morphologies on plates, and analysis of cell morphologies of isolated strains. Substantial numbers of viable bacteria (105‐108/g) were present in all transmissive, aquifer sediments, and their numbers did not decrease with depth. Fewer bacteria (<103/g) were detected in nontransmissive, confining layers. The highest viable counts were obtained on dilute media, but 10–50% of the bacteria in most aquifer sediments also grew rapidly on concentrated, nutrient‐rich media (indicating a high degree of metabolic flexibility). Most of the bacteria were mesophilic; relatively few psychrophiles or thermophiles were detected (<103/g; in many cases, none). The bacterial flora was diverse (11–62 distinct colony types on enumeration plates of most aquifer sediments). Diversity did not decrease with depth, but the composition of the microflora (based on colony analysis) varied extensively from one geological formation to another. Almost 95% of the platable colonies that grew on enumeration plates contained nonstreptomycete bacteria, more than 80% of which were gram‐negative rods. Light microscopy of films released from aquifer sediments by flotation revealed the presence of dividing cells and microcolonies, thus implying that the in situ deep aquifer microflora was more metabolically active than that seen previously in shallow aquifers. 相似文献
14.
More than 900 culturable, heterotrophic aerobic isolates were obtained from the sediments of a forested, pristine stream and analyzed using three classical microbiological tests: API 20E, amplified ribosomal DNA restriction analysis (ARDRA), and fatty acid analysis. Gram-negative bacteria comprised most of the heterotrophic aerobic isolates (66.7%), similar to other oligotrophic environments. The isolates were assigned to the genus level as Pseudomonas, Flavobacterium, Micrococcus, Bacillus, Chromobacterium, Acinetobacter, Alcaligenes, Aeromonas, Methylobacterium, Enterobacter, Corynebacterium, and Sporolactobacillus. Genotypic analysis by ARDRA facilitated the comparison among strains within Pseudomonas, Bacillus, and Enterobacter groups. Temperature and predation may influence the survival of bacteria during seasons, as shown previously by others. Our results showed that the number of heterotrophic aerobic bacteria, especially Enterobacter, Alcaligenes, and Aeromonas, and Gram-positive bacteria, decreased in winter compared to summer conditions. 相似文献
15.
Diversity and identification of methanogenic archaea and sulphate-reducing bacteria in sediments from a pristine tropical mangrove 总被引:1,自引:0,他引:1
Rodrigo Gouvêa Taketani Caio Augusto Yoshiura Armando Cavalcante Franco Dias Fernando Dini Andreote Siu Mui Tsai 《Antonie van Leeuwenhoek》2010,97(4):401-411
Mangrove sediments are anaerobic ecosystems rich in organic matter. This environment is optimal for anaerobic microorganisms,
such as sulphate-reducing bacteria and methanogenic archaea, which are responsible for nutrient cycling. In this study, the
diversity of these two functional guilds was evaluated in a pristine mangrove forest using denaturing gradient gel electrophoresis
(DGGE) and clone library sequencing in a 50 cm vertical profile sampled every 5.0 cm. DGGE profiles indicated that both groups
presented higher richness in shallow samples (0–30 cm) with a steep decrease in richness beyond that depth. According to redundancy
analysis, this alteration significantly correlated with a decrease in the amount of organic matter. Clone library sequencing
indicated that depth had a strong effect on the selection of dissimilatory sulphate reductase (dsrB) operational taxonomic units (OTUs), as indicated by the small number of shared OTUs found in shallow (0.0 cm) and deep
(40.0 cm) libraries. On the other hand, methyl coenzyme-M reductase (mcrA) libraries indicated that most of the OTUs found in the shallow library were present in the deep library. These results
show that these two guilds co-exist in these mangrove sediments and indicate important roles for these organisms in nutrient
cycling within this ecosystem. 相似文献
16.
In order to develop effective bioremediation strategies for radionuclide contaminants, the composition and metabolic potential of microbial communities need to be better understood, especially in highly contaminated subsurface sediments for which little cultivation-independent information is available. In this study, we characterized metabolically active and total microbial communities associated with uranium-contaminated subsurface sediments along geochemical gradients. DNA and RNA were extracted and amplified from four sediment-depth intervals representing moderately acidic (pH 3.7) to near-neutral (pH 6.7) conditions. Phylotypes related to Proteobacteria (Alpha-, Beta-, Delta- and Gammaproteobacteria), Bacteroidetes, Actinobacteria, Firmicutes and Planctomycetes were detected in DNA- and RNA-derived clone libraries. Diversity and numerical dominance of phylotypes were observed to correspond to changes in sediment geochemistry and rates of microbial activity, suggesting that geochemical conditions have selected for well-adapted taxa. Sequences closely related to nitrate-reducing bacteria represented 28% and 43% of clones from the total and metabolically active fractions of the microbial community, respectively. This study provides the first detailed analysis of total and metabolically active microbial communities in radionuclide-contaminated subsurface sediments. Our microbial community analysis, in conjunction with rates of microbial activity, points to several groups of nitrate-reducers that appear to be well adapted to environmental conditions common to radionuclide-contaminated sites. 相似文献
17.
Huang Jingyu Wang Xia Wang Xiaoyan Chen Yongjuan Yang Zhiwei Xie Shuguang Li Tingting Song Shuang 《Aquatic Ecology》2022,56(3):841-857
Aquatic Ecology - Ammonia oxidation driven by ammonia-oxidizing archaea (AOA) and bacteria (AOB) plays a significant role in the nitrogen cycle, but the mechanism of this important action... 相似文献
18.
Isolation and characterization of quinoline-degrading bacteria from subsurface sediments 总被引:1,自引:0,他引:1
F J Brockman B A Denovan R J Hicks J K Fredrickson 《Applied and environmental microbiology》1989,55(4):1029-1032
Two gram-negative, motile bacteria isolated from deep subsurface sediments mineralized the nitrogen-containing polyaromatic hydrocarbon quinoline under aerobic conditions and transformed quinoline to soluble intermediates under anaerobic conditions. Many aromatic compounds were also able to serve as the sole source of carbon and energy under aerobic conditions. Rapid aerobic mineralization of quinoline at concentrations as low as 0.002 microgram ml-1 indicates that these organisms possess a high-affinity uptake and utilization system, which may reflect the oligotrophic nature of deep subsurface environments. Both bacteria harbored four plasmids of identical size, ranging from 50 to 440 kilobases. 相似文献
19.
R. H. Vreeland A. F. Piselli Jr. S. McDonnough S. S. Meyers 《Extremophiles : life under extreme conditions》1998,2(3):321-331
The Waste Isolation Pilot Plant (WIPP) is a salt mine constructed 650 meters below the ground surface by the United States
Department of Energy. The facility will be used for permanent disposal of transuranic wastes. This underground repository
has been constructed in the geologically stable Permian age Salado salt formation. Of the wastes to be placed into the facility,
85% will be biodegradable cellulose. A 3-year survey of the bacterial populations existing within the facility was conducted.
Bacterial populations were found to be heterogeneously distributed throughout the mine. Populations in some mine areas reached
as high as 1.0 × 104 colony-forming units per gram of NaCl. The heterogeneous distribution of bacteria within the mine did not follow any recognizable
pattern related to either age of the workings or to human activity. A biochemical comparison between ten known species of
halophilic bacteria, and strains isolated from both the mine and nearby surface hypersaline lakes, showed the presence of
extreme halophiles with wide biochemical diversity, some of which could prove to represent previously undescribed groups.
The halophilic bacteria isolated from the mine were found to degrade cellulose and a wide variety of other carbon compounds.
When exposed to two types of common laboratory paper, the cellulose-degrading halophiles attached to the substrate within
30 minutes of inoculation. Cultures enriched directly from a brine seep in the mine easily destroyed both papers and produced
detectable amounts of oxalacetic and pyruvic acids. The combination of heterogeneity in the distribution of organisms, the
presence of a physiologically diverse community, and the relatively slow metabolism of cellulose may explain several long-standing
debates about the existence of microorganisms in ancient underground salt formations.
Received: September 29, 1997 / Accepted: January 29, 1998 相似文献
20.
Recently attempts have been made to establish the presence and to determine the metabolic versatility of microorganisms in
the terrestrial deep subsurface at the Savannah River Plant, Aiken, SC, USA. Sediment samples obtained at 20 different depths
of up to 526 m were examined to determine carbon mineralization under aerobic, sulfate-reducing, and methanogenic conditions.
The evolution of14CO2 from radiolabelled glucose was observed under aerobic conditions in all sediments, whereas pyridine was transformed in 50%
of the 20 sediments and indole was metabolized in 85% of the sediments. Glucose mineralization in certain sediments was comparable
to that in the surface environment. Sulfate was reduced in only five sediments, and two were carbon limited. Methane production
was detected in ten sediments amended with formate only after long-term incubations. The transformation of indole and pyridine
was only rarely observed under sulfate-reducing conditions and was never detected in methanogenic incubations. This study
provides information concerning the metabolic capability of both aerobic and anaerobic microorganisms in the deep subsurface
and may prove useful in determining the feasibility of microbial decontamination of such environments. 相似文献