Distribution of Archaea in a Black Smoker Chimney Structure

Archaeal community structures in microhabitats in a deep-sea hydrothermal vent chimney structure were evaluated through the combined use of culture-independent molecular analyses and enrichment culture methods. A black smoker chimney was obtained from the PACMANUS site in the Manus Basin near Papua New Guinea, and subsamples were obtained from vertical and horizontal sections. The elemental composition of the chimney was analyzed in different subsamples by scanning electron microscopy and energy-dispersive X-ray spectroscopy, indicating that zinc and sulfur were major components while an increased amount of elemental oxygen in exterior materials represented the presence of oxidized materials on the outer surface of the chimney. Terminal restriction fragment length polymorphism analysis revealed that a shift in archaeal ribotype structure occurred in the chimney structure. Through sequencing of ribosomal DNA (rDNA) clones from archaeal rDNA clone libraries, it was demonstrated that the archaeal communities in the chimney structure consisted for the most part of hyperthermophilic members and extreme halophiles and that the distribution of such extremophiles in different microhabitats of the chimney varied. The results of the culture-dependent analysis supported in part the view that changes in archaeal community structures in these microhabitats are associated with the geochemical and physical dynamics in the black smoker chimney.     

Geomicrobiological exploration and characterization of a novel deep-sea hydrothermal system at the TOTO caldera in the Mariana Volcanic Arc

Novel hydrothermal activities accompanying effluent white smokers and elemental sulfur chimney structures at the north-east lava dome of the TOTO caldera depression in the Mariana Volcanic Arc have been explored and characterized by geochemical and microbiological surveys. White smoker hydrothermal fluids were observed in the potential hydrothermal activity centre of the field and represented the maximal temperature of 170 degrees C and the lowest pH of 1.6. The chimney structures, all consisting of elemental sulfur (sulfur chimney), were also unique to the TOTO caldera hydrothermal field. Microbial community structures in a sulfur chimney and its formation hydrothermal fluid with a high concentration of hydrogen sulfide (15 mM) have been investigated by culture-dependent and -independent analyses. 16S rRNA gene clone analysis and fluorescence in situ hybridization (FISH) analysis revealed that epsilon-Proteobacteria dominated the microbial communities in the sulfur chimney structure and formed a dense microbial mat covering the sulfur chimney surface. Archaeal phylotypes were consistently minor components in the communities and related to the genera Thermococcus, Pyrodictium, Aeropyrum, and the uncultivated archaeal group of 'deep-sea hydrothermal vent euryarchaeotal group'. Cultivation analysis suggested that the chemolithoautotrophs might play a significant ecological role as primary producers utilizing gas and sulfur compounds provided from hydrothermal fluids.     

Bacterial and archaeal phylotypes associated with distinct mineralogical layers of a white smoker spire from a deep-sea hydrothermal vent site (9 degrees N, East Pacific Rise)

A diffusely venting chimney spire from the East Pacific Rise (9 degrees N) was analysed by petrographic thin sectioning and 16S rRNA gene cloning and sequencing in parallel, to correlate microbial community composition with mineralogy and inferred in situ conditions within the chimney mineral matrix. Both approaches indicated a zonation of the chimney spire into distinct microhabitats for different bacteria and archaea. The thermal gradient inferred from the mineral composition and porosity of the chimney was consistent with the distribution of bacterial and archaeal phylotypes in the chimney matrix. A novel phylogenetic lineage of euryarchaeota was found that co-occurred with clones related to cultured hyperthermophilic archaea. A few phylotypes related to mesophilic bacteria were found in the hot core of the chimney, indicating that seawater influx during retrieval and cooling of these highly porous structures can entrain microorganisms into chimney layers that are not their native habitat.     

Phylogenetic diversity of sulfate-reducing prokaryotes in active deep-sea hydrothermal vent chimney structures

The phylogenetic diversity of sulfate-reducing prokaryotes occurring in active deep-sea hydrothermal vent chimney structures was characterized based on the deduced amino acid sequence analysis of the polymerase chain reaction-amplified dissimilatory sulfite reductase (DSR) gene. The DSR genes were successfully amplified from microbial assemblages of the chimney structures, derived from three geographically and geologically distinct deep-sea hydrothermal systems in the Central Indian Ridge (CIR), in the Izu-Bonin Arc (IBA), and the Okinawa Trough (OT), respectively. Phylogenetic analysis revealed seven major phylogenetic groups. More than half of the clones from the CIR chimney structure were related to DSR amino acid sequences of the hyperthermophilic archaeal members of the genus Archaeoglobus, and those of environmental DSR clones within the class Thermodesulfobacteria. From the OT chimney structure, a different group was obtained, which comprised a novel, deep lineage associated with the DSRs of the thermophilic sulfate-reducing bacterium Thermodesulfovibrio. Most of the DSR clones from the IBA chimney structure were phylogenetically associated with the delta-proteobacterial sulfate-reducing bacteria represented by the genus Desulfobulbus. Sequence analysis of DSR clones demonstrated a diverse sulfate-reducing prokaryotic community in the active deep-sea hydrothermal chimney structures.     

Profile of Microbial Community Structure and Presence of Endolithic Microorganisms Inside a Deep-Sea Rock

Microbial community structure in the depth profile of a deep-sea sedimentary rock collected from the Sanriku Escarpment in the Japan Trench at a depth of 6337 m were analyzed using enrichment culture methods and culture-independent molecular phylo-genetic techniques. The rock was subsampled at four depths (S1 to S4; from the surface to the inside), and carbon concentrations and colony-forming units (CFU) were determined under several culture conditions. Terminal-restriction fragment length polymorphism (T-RFLP) analysis of PCR-amplified 16S rRNA gene (rDNA) sequences indicated that a shift in bacterial and archaeal ribotype structures occurred in the sections at different depths from the surface. rDNA clone analysis revealed a significant change in microbial rDNA community structure. Bacterial community rDNA in sections S1 to S3 consisted of typical marine bacteria mainly members of the f and n -subclass of Proteobacteria, while the inner most section, S4, contained rDNA signatures for the g -subclass of Proteobacteria and the High G + C Gram-Positive Group. Major archaeal rDNA clones shifted from Marine Group I (S1) to Thermococcales (S2-S4). The changes in bacterial and archaeal rDNA community structure indicated the possible infiltration of seawater and microorganisms into the rock and strongly suggested the isolation of endolithic microbial communities over the geological history of the rock.     

Archaeal diversity associated with in situ samplers deployed on hydrothermal vents on the East Pacific Rise (13 degrees N)

To evaluate possible compositional changes in archaeal communities at a deep-sea hydrothermal vent field scale, we examined five different samples obtained after deploying in situ collectors for different times on three spatially separated venting sulphide structures on the East Pacific Rise (13 degrees N). Direct cell counts and whole-cell hybridizations with fluorescently labelled 16S rRNA-based oligonucleotide probes revealed that the relative abundance of archaeal populations represented from 14 to 33% of the prokaryotic community. 16S rDNA sequence analysis of the archaeal clone libraries indicated that a large percentage of clones were closely related to known archaeal isolates recovered from similar habitats. Among the 24 different phylotypes identified, Thermococcales-related sequences were dominant in all the libraries that also included representative genera of orders Methanopyrales, Methanococcales, Archaeoglobales and Desulfurococcales. The presence of most of these phylogenetic groups was confirmed in enrichment cultures performed at temperatures from 60 to 90 degrees C. Additional sequences with no known cultivated relatives grouped with the Marine group I Crenarchaeota, Korarchaeota and Deep-sea Hydrothermal Vent Euryarchaeota (DHVE) within which a novel lineage was identified. Furthermore, the archaeal community composition was distinct from vent to vent within the same vent field and varied within short time scales. This study provides new insights into microbial diversity and distribution at deep-sea hydrothermal vents.     

Examination of two years of community dynamics in an anaerobic bioreactor using fluorescence polymerase chain reaction (PCR) single-strand conformation polymorphism analysis

The structures of the bacterial and archaeal communities in an anaerobic digester were monitored over a 2 year period. The study was performed on a fluidized bed reactor fed with vinasse. The objective was to characterize the population dynamics over a long time period under constant environmental parameters. Total bacterial and archaeal populations were measured independently by fluorescence-based polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) analysis using an automated DNA sequencer. With the current level of accuracy, the technique was able to monitor 45 bacterial and seven archaeal 16S rDNA molecules. The community dynamics were compared with molecular inventories of the microbial community based on 16S rDNA sequences done at the beginning of the study. The six archaeal and the 22 most frequent bacterial operational taxonomic units (OTUs) identified were associated with their SSCP peak counterparts. Overall, the data indicated that, throughout the period of the study, rapid significant shifts in the species composition of the bacterial community occurred, whereas the archaeal community remained relatively stable.     

DGGE method for analyzing 16S rDNA of methanogenic archaeal community in paddy field soil

A denaturing gradient gel electrophoresis (DGGE) method for analyzing 16S rDNA of methanogenic archaeal community in paddy field soil is presented. Five specific primers for 16S rDNA of methanogenic archaea, which were modified from the primers for archaea, were first evaluated by polymerase chain reaction and DGGE using genomic DNAs of 13 pure culture strains of methanogenic archaea. The DGGE analysis was possible with two primer pairs (0348aF-GC and 0691R; 0357F-GC and 0691R) of the five pairs tested although 16S rDNA of some non-methanogenic archaea was amplified with 0348aF-GC and 0691R. These two primer pairs were further evaluated for use in analysis of methanogenic archaeal community in Japanese paddy field soil. Good separation and quality of patterns were obtained in DGGE analysis with both primer pairs. A total of 41 DNA fragments were excised from the DGGE gels and their sequences were determined. All fragments belonged to methanogenic archaea. These results indicate that the procedure of DGGE analysis with the primer pair 0357F-GC and 0691R is suitable for investigating methanogenic archaeal community in paddy field soil.     

Shifts in archaeal communities associated with lithological and geochemical variations in subsurface Cretaceous rock

Subsurface microbial community structure in relation to geochemical gradients and lithology was investigated using a combination of molecular phylogenetic and geochemical analyses. Discreet groundwater and substratum samples were obtained from depths ranging from 182 to 190 m beneath the surface at approximately 10-cm intervals using a multilevel sampler (MLS) that straddled Cretaceous shale and sandstone formations at a site in the southern San Juan Basin in New Mexico. DNA and RNA were extracted directly from quartzite sand substratum loaded into individual cells of the MLS and colonized in situ. Polymerase chain reaction (PCR)-mediated T-RFLP analysis of archaeal rRNA genes (rDNA) in conjunction with partial sequencing analysis of archaeal rDNA libraries and quantitative RNA hybridization with oligonucleotide probes were used to probe community structure and function. Although total microbial populations remained relatively constant over the entire depth interval sampled, significant shifts in archaeal populations, predominantly methanogens, were observed. These shifts coincided with the geochemical transition from relatively high methane (26 mM), low sulphate (< 3 mg l(-1)) conditions in the region adjacent to the organic matter-rich shale to relatively low-methane (< 0.5 mM), high-sulphate (48 mg l(-1)) conditions in the organic-poor sandstone beneath the shale. These results indicated that active, phylogenetically diverse archaeal communities were present in the subsurface Cretaceous rock environment at this site and that major archaeal clades shifted dramatically over scales of tens of centimetres, corresponding to changes in the lithology and geochemical gradients.     

灌木林土壤古菌群落结构对地表野火的快速响应

为了评价地表野火对土壤古菌群落结构的即时影响,在灌木林火发生18h后,于火烧迹地和未烧地采集土壤样品,通过构建两个土壤古菌16S rDNA基因文库,研究火烧后小时尺度下土壤古菌群落结构的变化。从火烧和对照未烧土壤古菌文库中共得到19个古菌的操作分类单元 (Operation taxonomic units,OTUs),其中对照未烧林地土壤文库中存在9个OTUs是火烧土壤中缺失的类群,占克隆总数的5.91%。未烧林地中3个优势古菌克隆YMar-F25（GQ304791）、YMar-F32（GQ304792）及YMar-F21（GQ304789）系统发育归类为泉古菌门亚群GroupⅠ,分别占克隆总数的15.50%,18.18%,41.36%;而在火烧迹地中这3个古菌分类群仍为优势群,分别占克隆总数的15.59%,22.58%,46.24%。多样性指数分析显示对照土壤古菌文库Shannon-Wiener指数为1.87,而火烧土壤古菌文库为1.40。结果表明,在小时尺度上,高强度灌木林火使土壤古菌多样性立即降低,低丰度土壤古菌种群对火干扰敏感,高丰度古菌的种群结构火烧后无明显变化。     

Microbial diversity of Loki's Castle black smokers at the Arctic Mid‐Ocean Ridge

Hydrothermal vent systems harbor rich microbial communities ranging from aerobic mesophiles to anaerobic hyperthermophiles. Among these, members of the archaeal domain are prevalent in microbial communities in the most extreme environments, partly because of their temperature‐resistant and robust membrane lipids. In this study, we use geochemical and molecular microbiological methods to investigate the microbial diversity in black smoker chimneys from the newly discovered Loki's Castle hydrothermal vent field on the Arctic Mid‐Ocean Ridge (AMOR) with vent fluid temperatures of 310–320 °C and pH of 5.5. Archaeal glycerol dialkyl glycerol tetraether lipids (GDGTs) and H‐shaped GDGTs with 0–4 cyclopentane moieties were dominant in all sulfide samples and are most likely derived from both (hyper)thermophilic Euryarchaeota and Crenarchaeota. Crenarchaeol has been detected in low abundances in samples derived from the chimney exterior indicating the presence of Thaumarchaeota at lower ambient temperatures. Aquificales and members of the Epsilonproteobacteria were the dominant bacterial groups detected. Our observations based on the analysis of 16S rRNA genes and biomarker lipid analysis provide insight into microbial communities thriving within the porous sulfide structures of active and inactive deep‐sea hydrothermal vents. Microbial cycling of sulfur, hydrogen, and methane by archaea in the chimney interior and bacteria in the chimney exterior may be the prevailing biogeochemical processes in this system.     

The impact of grassland management on archaeal community structure in upland pasture rhizosphere soil

The community structure of rhizosphere soil Archaea from three grassland types, associated with different management practices, was examined at a site in the Borders region of Scotland, by analysis of 16S rRNA gene fragments amplified from 16S rDNA and from rRNA. Denaturing gradient gel electrophoresis (DGGE) and sequence analysis of amplified products indicated high relative abundance within the archaeal community of two distinct lineages of non-thermophilic (group 1) Crenarchaeota. Grassland management practices influenced archaeal community structure, as characterized by both 16S rRNA- and 16S rDNA-derived DGGE profiles. One band dominated DGGE profiles in all three grassland types examined, and reproducible differences in the presence and intensity of bands were observed between profiles from managed and natural grassland sites. Analysis of 16S rRNA-derived amplicons from managed and natural grasslands at sites in the north of England and the north of Wales also indicated high relative abundance of non-thermophilic crenarchaeotes within the archaeal community. The band dominating the Scottish grassland site also dominated DGGE profiles from the English and Welsh sites, and similar differences were seen between profiles derived from soils subjected to different management regimes. The study indicates that grassland archaeal communities are dominated by Crenarchaeota, with closely related members of this lineage ubiquitous in distribution in UK upland pasture, and indicate that management practices influence the nature of the crenarchaeotal community.     

Molecular analysis of microbial community structure in an arsenite-oxidizing acidic thermal spring

Electron microscopy (EM), denaturing gradient gel electrophoresis (DGGE) and 16S rDNA sequencing were used to examine the structure and diversity of microbial mats present in an acid-sulphate–chloride (pH 3.1) thermal (58–62°C) spring in Norris Basin, Yellowstone National Park, WY, USA, exhibiting rapid rates of arsenite oxidation. Initial visual assessments, scanning EM and geochemical measurements revealed the presence of three distinct mat types. Analysis of 16S rDNA fragments with DGGE confirmed the presence of different bacterial and archaeal communities within these zones. Changes in the microbial community appeared to coincide with arsenite oxidation activity. Phylogenetic analysis of 1400 bp 16S rDNA sequences revealed that clone libraries prepared from both arsenic redox active and inactive bacterial communities were dominated by sequences phylogenetically related to Hydrogenobacter acidophilus and Desulphurella sp. The appearance of archaeal 16S rDNA sequences coincided with the start of arsenite oxidation, and sequences were obtained showing affiliation with both Crenarchaeota and Euryarchaeota . The majority of archaeal sequences were most similar to sequences obtained from marine hydrothermal vents and other acidic hot springs, although the level of similarity was typically just 90%. Arsenite oxidation in this system may result from the activities of these unknown archaeal taxa and/or the previously unreported arsenic redox activity of H. acidophilus - or Desulphurella -like organisms. If the latter, arsenite oxidation must be inhibited in the initial high-sulphide zone of the spring, where no change in the distribution of arsenite versus arsenate was observed.     

Diversity and structure of the archaeal community in the leachate of a full-scale recirculating landfill as examined by direct 16S rRNA gene sequence retrieval

The diversity and structure of the archaeal community in the effluent leachate from a full-scale recirculating landfill was characterized by direct 16S rRNA gene (16S rDNA) retrieval. Total-community DNA was extracted from the microbial assemblages in the landfill leachate, and archaeal 16S rDNAs were amplified with a universally conserved primer and an Archaea-specific primer. The amplification product was then used to construct a 16S rDNA clone library, and 70 randomly selected archaeal clones in the library were grouped by restriction fragment length polymorphism (RFLP) analysis. Sequencing and phylogenetic analysis of representatives from each unique RFLP type showed that the archaeal library was dominated by methanogen-like rDNAs. Represented in the kingdom of Euryarchaeota were phylotypes highly similar to the methanogenic genera Methanoculleus, Methanosarcina, Methanocorpusculum, Methanospirillum and Methanogenium, where the clone distribution was 48, 11, 3, 1 and 1, respectively. No sequences related to known Methanosaeta spp. were retrieved. Four rDNA clones were not affiliated with the known methanogenic Archaea, but instead, they were clustered with the uncultured archaeal sequences recently recovered from anaerobic habitats. Two chimeric sequences were identified among the clones analyzed.     

Culture dependent and independent analyses of 16S rRNA and ATP citrate lyase genes: a comparison of microbial communities from different black smoker chimneys on the Mid-Atlantic Ridge

The bacterial and archaeal communities of three deep-sea hydrothermal vent systems located on the Mid-Atlantic Ridge (MAR; Rainbow, Logatchev and Broken Spur) were investigated using an integrated culture-dependent and independent approach. Comparative molecular phylogenetic analyses, using the 16S rRNA gene and the deduced amino acid sequences of the alpha and beta subunits of the ATP citrate lyase encoding genes were carried out on natural microbial communities, on an enrichment culture obtained from the Broken Spur chimney, and on novel chemolithoautotrophic bacteria and reference strains originally isolated from several different deep-sea vents. Our data showed that the three MAR hydrothermal vent chimneys investigated in this study host very different microbial assemblages. The microbial community of the Rainbow chimney was dominated by thermophilic, autotrophic, hydrogen-oxidizing, sulfur- and nitrate-reducing Epsilonproteobacteria related to the genus Caminibacter. The detection of sequences related to sulfur-reducing bacteria and archaea (Archaeoglobus) indicated that thermophilic sulfate reduction might also be occurring at this site. The Logatchev bacterial community included several sequences related to mesophilic sulfur-oxidizing bacteria, while the archaeal component of this chimney was dominated by sequences related to the ANME-2 lineage, suggesting that anaerobic oxidation of methane may be occurring at this site. Comparative analyses of the ATP citrate lyase encoding genes from natural microbial communities suggested that Epsilonproteobacteria were the dominant primary producers using the reverse TCA cycle (rTCA) at Rainbow, while Aquificales of the genera Desulfurobacterium and Persephonella were prevalent in the Broken Spur chimney.     

Diversity of symbiotic archaeal communities in marine sponges from Korea

A molecular analysis of archaeal communities in eight sponges collected along the coast of Cheju Island, Korea was conducted using terminal-restriction fragment length polymorphism (T-RFLP) in conjunction with sequencing analysis of 16S rDNA clones. The terminal-restriction fragment (T-RF) profiles showed that each sponge had a simple archaeal community represented by a single major peak of the same size except for one unidentified sponge (01CJ20). In order to identify the components of the community, 170 archaeal 16S rDNA clones were recovered from sponges and analyzed by RFLP typing. Sequences of 19 representative clones for all RFLP types found in each sponge were determined and phylogenetic analysis was carried out. Seventeen of these archaeal 16S rDNA clones showed a high similarity to marine group I, belonging to the crenarchaeotes. In the phylogenetic tree, 15 archaeal clones were grouped into five sponge-associated archaeal clusters. In the unidentified sponge sample (01CJ20), one major T-RF peak was represented by a single RFLP type (40 clones), which implied a specific relationship between the sponge and its symbiotic archaeal components.     

Diversity and Community Structure of Archaea in Deep Subsurface Sediments from the Tropical Western Pacific

Archaeal 16S rRNA gene clone libraries using PCR amplicons from eight different layers of the MD06-3051 core were obtained from the tropical Western Pacific sediments. A total of 768 clones were randomly selected, and 264 representative clones were sequenced by restriction fragment length polymorphism. Finally, 719 valid clones and 104 operational taxonomic units were identified after chimera-check and ≥97% similarity analysis. The phylogenetic analysis of 16S rDNA sequences obtained from sediment samples were very diverse and showed stratification with depth. Majority of the members were most closely related to uncultivated groups and physiologically uncharacterized assemblages. All phylotypes were affiliated with Crenarchaeota (76%) and Euryarchaeota (24%), respectively. Deep-sea archaeal group (DSAG, 41% of total clones) and miscellaneous crenarchaeotic group (MCG, 29% of total clones) belonging to Crenarchaeota were the most predominant archaeal 16S rDNA phylotypes in clone libraries. Phylotypes in this study shared high similarity with those in subsurface sediments from Peru Margin sites, which indicated that different geographical zones might host similar members of archaeal populations based on similar sedimentary environments. In our study, members of DSAG and MCG seemed to dominate certain layers of the nonhydrate sediments, suggesting a wide ecophysiological adaptation than previously appreciated. The spatial distribution and community structure of these groups might vary with the different geochemical gradients of the environment.     

垃圾填埋场渗滤液中古细菌群落16S rRNA基因的ARDRA分析

利用特异性的引物对,选择性扩增垃圾填埋场渗滤液中古细菌群落的18S rRNA基因片断,在此基础上建立16S rDNA克隆文库,经古细菌通用寡核苷酸探针的原位杂交筛选后,克隆文库内古细菌16S rDNA扩增片断的多样性通过ARDRA分析（amplified rDNA restriction analysis)而获得,利用PCR将各组重克隆子内的16S rDNA外源片断再扩增出来后,两种限制性内切酶－Hha I和HaeⅢ－被分别用于16S rDNA克隆片断的限制酶切分析,结果表明,随机选出的70个古细菌16S rDNA克隆片断被妥为21个不同的ARDRA型（组）,其中的两个优势型总共占了所有被分析克隆子的60％,而其余19个型的相对丰度均处于较低的水平,当中的14个型更仅含有1个克隆子,通过对16S rRNA基因的PCR扩增,克隆及其ARDRA分析,能快速地获得有关填埋场渗滤液中古细菌群落的结构及其多样性的初步信息。     

Axial differences in community structure of Crenarchaeota and Euryarchaeota in the highly compartmentalized gut of the soil-feeding termite Cubitermes orthognathus

Methanogenesis represents an important electron sink reaction in the hindgut of soil-feeding termites. This is the first comprehensive analysis of the archaeal community structure within the highly compartmentalized intestinal tract of a humivorous insect, combining clonal analysis and terminal restriction fragment (T-RF) length polymorphism (T-RFLP) fingerprinting of the archaeal communities in the different gut compartments of Cubitermes orthognathus. We found that the morphological and physicochemical heterogeneity of the gut is reflected in a large phylogenetic diversity and pronounced axial differences in the composition of the archaeal gut microbiota, notably among those clones or ribotypes that could be assigned to methanogenic taxa. Comparative analysis of the relative frequencies of different archaeal lineages among the small-subunit rRNA gene (SSU rDNA) clones and their corresponding T-RF indicated that the archaeal community in the anterior, extremely alkaline hindgut compartment (P1) consists mainly of members of the Methanosarcinaceae, whereas Methanobacteriaceae and Methanomicrobiales predominate in the subsequent, more posterior compartments (P3/4a and P4b). The relative abundance of Thermoplasmales increased towards the rectum (P5). SSU rDNA sequences representing Crenarchaeota, which have not yet been reported to occur in the intestinal tracts of arthropods, were detected in all gut sections. We discuss how the spatial distribution of methanogenic populations may be linked to axial heterogeneity in the physicochemical gut conditions and to functional adaptations to their respective ecological niches.     

河北兴隆中元古代古海底黑烟囱中微生物化石的发现及其意义

采用显微镜以及扫描电镜对冀东中元古代块状硫化物黑烟囱样品进行研究,首次发现了矿化微生物化石。它们为丝状体,均已黄铁矿化,经过激光拉曼光谱测试发现还保留少量有机质,可以与现代海底黑烟囱周围矿化微生物对比。这些化石微生物的鉴别基于大小、形状和群落聚集等物理标志。