Sequestration of arsenic to biogenic sulfide minerals is known from As-contaminated anoxic environments. Despite numerous successful laboratory experiments, the process remains difficult to predict in moderate arsenic conditions. We performed microcosm experiments using naturally contaminated groundwater (containing ca. 6 mg/L As) and natural organic matter (NOM) particles both collected from wetland soil. Macroscopic realgar precipitates, occasionally accompanied by bonazziite, a FeS phase, elementary S, calcite, and whewellite, appeared after 4 to 18 months. Realgar only precipitated in microcosms moderately poisoned by azide or antibiotics and those in which oxidation of hydrogen sulfide to sulfur took place. The biomineralization process was not affected by the presence of additional carbon sources or the diversity, community structure, and functional composition of the microbial community. Hydrogen sulfide concentration was greater in the realgar-free microcosms, suggesting that arsenic thiolation prevented precipitation of realgar. We compared our data to available microbial community data from soils with different rates of realgar precipitation, and found that the communities from realgar-encrusted NOM particles usually showed limited sulfate reduction and the presence of fermentative metabolisms, whereas communities from realgar-free NOM particles were strongly dominated by sulfate reducers. We argue that the limited sulfate supply and intensive fermentation amplify reducing conditions, which make arsenic sulfide precipitation plausible in high-sulfate, low-arsenic groundwaters.
- MeSH
- arsenikové přípravky analýza MeSH
- biomineralizace * MeSH
- chemické látky znečišťující vodu analýza MeSH
- huminové látky analýza MeSH
- mikrobiota * MeSH
- mokřady MeSH
- oxidace-redukce MeSH
- podzemní voda chemie mikrobiologie MeSH
- půda chemie MeSH
- sírany chemie MeSH
- sulfidy analýza MeSH
- teoretické modely MeSH
- Publikační typ
- časopisecké články MeSH
Deep sequencing of prokaryotic 16S rDNA regularly reveals thousands of microbial species thriving in many common habitats. It is still unknown how this huge microbial diversity, including many potentially competing organisms, may persist at a single site. One of plausible hypotheses is that a large number of spatially separated microcommunities exist within each complex habitat. Smaller subset of the species may exist in each microcommunity and actually interact with each other. We sampled two groups of microbial stalactites growing at a single acidic mine drainage outlet as a model of multiplicated, low-complexity microhabitat. Samples from six other sites were added for comparison. Both tRFLP and 16S rDNA pyrosequencing showed that microbial communities containing 6 to 51 species-level operational taxonomic units (OTU) inhabited all stalactites. Interestingly, most OTUs including the highly abundant ones unpredictably alternated regardless of physical and environmental distance of the stalactites. As a result, the communities clustered independently on sample site and other variables when using both phylogenetic dissimilarity and OTU abundance metrics. Interestingly, artificial communities generated by pooling the biota of several adjacent stalactites together clustered by the locality more strongly than when the stalactites were analyzed separately. The most probable interpretation is that each stalactite contains likely random selection from the pool of plausible species. Such degree of stochasticity in assembly of extremophilic microbial communities is significantly greater than commonly proposed and requires caution when interpreting microbial diversity.
- MeSH
- Bacteria klasifikace izolace a purifikace metabolismus MeSH
- biodiverzita MeSH
- biofilmy MeSH
- DNA bakterií genetika MeSH
- druhová specificita MeSH
- fylogeneze * MeSH
- hornictví * MeSH
- kyseliny chemie MeSH
- mikrobiologie vody * MeSH
- RNA ribozomální 16S genetika MeSH
- sekvenční analýza DNA MeSH
- shluková analýza MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
A wide variety of microhabitats within the extremely acidic abandoned underground copper mine Zlaté Hory (Czech Republic) was investigated. SSU rDNA libraries were analyzed from 15 samples representing gossan, sulfide-leaching environments in the oxidation zone, and acidic water springs in the mine galleries. Microbial analyses were extended by analyses of chemical composition of water and solid phases and identification of arising secondary minerals. The microbial communities of the three main classes of microenvironments differed in almost every aspect. Among others, ecological partitioning of Acidithiobacillus ferrooxidans and the recently described A. ferrivorans was observed. Distinct types of communities inhabiting the water springs were detected. The more extreme springs (pH <3, conductivity >2 mS/cm) were inhabited by "Ferrovum" spp. and A. ferrivorans, whereas Gallionella sp. dominated the less extreme ones. A new role for gossan in the extremely acidic ecosystem is proposed. This zone was inhabited by a large diversity of neutrophilic heterotrophs that appeared to be continuously washed out to the acidic environments localized downstream. Five species originating in gossan were found in several acidic habitats. Here they can survive and probably serve as scavengers of dead biomass, particularly from chemoautotrophic growths. No such process has been described from acidic mine environments so far.
- MeSH
- Acidithiobacillus genetika izolace a purifikace MeSH
- Bacteria genetika izolace a purifikace MeSH
- bakteriální geny MeSH
- biodiverzita MeSH
- ekosystém * MeSH
- fylogeneze MeSH
- Gallionellaceae genetika izolace a purifikace MeSH
- geny rRNA MeSH
- geologické sedimenty chemie mikrobiologie MeSH
- hornictví MeSH
- koncentrace vodíkových iontů MeSH
- minerály MeSH
- sulfidy MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
112 s. : il. ; 21 cm
- MeSH
- biologické jevy MeSH
- biologie MeSH
- ekosystém MeSH
- fyziologie buňky MeSH
- Publikační typ
- příručky MeSH
- Konspekt
- Biologické vědy
- NLK Obory
- biologie
- biochemie
- fyziologie
