Results 11 -
19 of
19
Diversity of Life at the Geothermal Subsurface-Surface Interface: The Yellowstone Example Geophysical Monograph Series
"... Generally, studies of the terrestrial example of Yellowstone National Park indicate that the diversity of microbial life at the geothermal subsurface-surface interface is considerable. On the other hand, experiments in a subsurface well in Biscuit Basin suggest that the Yellowstone subsurface is hi ..."
Abstract
- Add to MetaCart
(Show Context)
Generally, studies of the terrestrial example of Yellowstone National Park indicate that the diversity of microbial life at the geothermal subsurface-surface interface is considerable. On the other hand, experiments in a subsurface well in Biscuit Basin suggest that the Yellowstone subsurface is highly reduced, with minimal in situ subsurface life at this location. The absence of life in the subsurface is likely due to low concentrations of available electron acceptors. Where subsurface thermal waters emerge to the surface, however, in the presence of oxidizing electron acceptors, microbial life blossoms on all growth surfaces at high temperatures. The geothermal subsurface-surface interface in the presence of both electron donors and acceptors, provides the key location for life to thrive and forms the cornerstone of the microbial ecosystem. Through molecular analyses, the identities of organisms present in a community can be determined by their phylogenetic types (phylotypes), their molecular signatures. Molecular sequences allow relationships to other life forms to be inferred. Comparisons of gene sequences of organisms and consideration of the geochemistry of a particular environment can help to explain how this geothermal system functions. Experimental results challenge some popular notions about the kinds of organisms that inhabit the geothermal realms and the energy sources that fuel them. In contrast to the popular notion that representatives of the phylogenetic domain Archaea dominate high-temperature ecosystems, members of the domain Bacteria are most abundant in the Yellowstone ecosystem. Moreover, while sulfur metabolism is generally proposed to be the primary energy source for life in this geothermal system, the main organisms identified by phylotype are related to organisms that utilize hydrogen, not sulfur, for energy. This implies that hydrogen is the main energy source that drives primary productivity in this and potentially other geothermal ecosystems. Primary dependence on hydrogen metabolism could be the common theme for high-temperature life in hydrothermal zones at mid-oceanic ridges, as well as for the earliest life on Earth and, potentially, for life on other planetary bodies.
Summary
"... doi:10.1111/j.1462-2920.2007.01506.x Cultivation of a thermophilic ammonia oxidizing archaeon synthesizing crenarchaeol ..."
Abstract
- Add to MetaCart
(Show Context)
doi:10.1111/j.1462-2920.2007.01506.x Cultivation of a thermophilic ammonia oxidizing archaeon synthesizing crenarchaeol
, Frontier
"... A polyphasic taxonomic study was performed on a novel facultatively anaerobic, hydrogen- or sulfur/thiosulfate-oxidizing, thermophilic chemolithoautotroph recently isolated from subsurface hot aquifer water in a Japanese gold mine. The cells were straight to slightly curved rods, with a single polar ..."
Abstract
- Add to MetaCart
(Show Context)
A polyphasic taxonomic study was performed on a novel facultatively anaerobic, hydrogen- or sulfur/thiosulfate-oxidizing, thermophilic chemolithoautotroph recently isolated from subsurface hot aquifer water in a Japanese gold mine. The cells were straight to slightly curved rods, with a single polar flagellum. Growth was observed at 40–70˚C (optimum 60–65˚C; 80 min doubling time) and at pH 6?4–8?8 (optimum pH 7?5). The isolate was unable to use complex organic compounds, carbohydrates, amino acids or organic acids as sole energy and carbon sources. The G+C content of the genomic DNA was 31?3 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was closely related to an uncultivated group of micro-organisms within the order Aquificales obtained from Icelandic and Japanese hot spring microbial mats, but distantly related to previously identified genera of the Aquificales such as Persephonella, Aquifex and Hydrogenobacter. The name Sulfurihydrogenibium subterraneum gen. nov., sp. nov. is proposed for this novel species; the type strain is HGMK1 T (=JCM 11477 T =ATCC BAA-562 T =DSM 15120 T). Culture-resistant phylotypes of thermophiles within the order Aquificales are potentially prevalent in microbial communities occurring in a certain temperature range (50–90 uC) in habitats in global terrestrial hot spring environments such as in Yellowstone National Park
www.mdpi.com/journal/ijerph Article Microbiological Analysis in Three Diverse Natural Geothermal Bathing Pools in Iceland
, 2013
"... Abstract: Natural thermal bathing pools contain geothermal water that is very popular to bathe in but the water is not sterilized, irradiated or treated in any way. Increasing tourism in Iceland will lead to increasing numbers of bath guests, which can in turn affect the microbial flora in the pools ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract: Natural thermal bathing pools contain geothermal water that is very popular to bathe in but the water is not sterilized, irradiated or treated in any way. Increasing tourism in Iceland will lead to increasing numbers of bath guests, which can in turn affect the microbial flora in the pools and therefore user safety. Today, there is no legislation that applies to natural geothermal pools in Iceland, as the water is not used for consumption and the pools are not defined as public swimming pools. In this study, we conducted a microbiological analysis on three popular but different natural pools in Iceland, located at Lýsuhóll, Hveravellir and Landmannalaugar. Total bacterial counts were performed by flow cytometry, and with plate count at 22 °C, 37 °C and 50 °C. The presence of viable coliforms, Enterococcus spp. and pseudomonads were investigated by growth experiments on selective media. All samples were screened for noroviruses by real time PCR. The results indicate higher fecal contamination in the geothermal pools where the geothermal water flow was low and bathing guest count was high during the day. The number of cultivated Pseudomonas spp. was high (13,000–40,000 cfu/100 mL) in the natural pools, and several strains were isolated and classified as opportunistic pathogens. Norovirus was
The Development and Optimization of Microbial Molecular
, 2006
"... Molecular Biomarkers for the in situ assessment of trace metal toxicity by ..."
Abstract
- Add to MetaCart
Molecular Biomarkers for the in situ assessment of trace metal toxicity by
Research Article Microbial Diversity and Biochemical Potential Encoded by Thermal Spring Metagenomes Derived from the Kamchatka Peninsula
, 2013
"... Copyright © 2013 Bernd Wemheuer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Volcanic regions contain a variety of environm ..."
Abstract
- Add to MetaCart
Copyright © 2013 Bernd Wemheuer et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Volcanic regions contain a variety of environments suitable for extremophiles. This study was focused on assessing and exploiting the prokaryotic diversity of two microbial communities derived from different Kamchatkian thermal springs by metagenomic approaches. Samples were taken from a thermoacidophilic spring near the Mutnovsky Volcano and from a thermophilic spring in the Uzon Caldera. Environmental DNA for metagenomic analysis was isolated from collected sediment samples by direct cell lysis. The prokaryotic community composition was examined by analysis of archaeal and bacterial 16S rRNA genes. A total number of 1235 16S rRNA gene sequences were obtained and used for taxonomic classification.Most abundant in the samples weremembers of Thaumarchaeota,Thermotogae, and Proteobacteria. TheMutnovsky hot spring was dominated by the Terrestrial Hot Spring Group, Kosmotoga, and Acidithiobacillus. The Uzon Caldera was dominated by uncultured members of the Miscellaneous Crenarchaeotic Group and Enterobacteriaceae. The remaining 16S rRNA gene sequences belonged to the Aquificae, Dictyoglomi, Euryarchaeota, Korarchaeota, Thermodesulfobacteria, Firmicutes, and some potential new phyla. In addition, the recovered DNA was used for generation of metagenomic libraries, which were subsequently mined for genes encoding lipolytic and proteolytic enzymes. Three
SEE PROFILE
"... All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. ..."
Abstract
- Add to MetaCart
(Show Context)
All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Microbial Diversity in Baltic Sea Sediments
"... This thesis focuses on microbial community structures and their functions in Baltic Sea sediments. First we investigated the distribution of archaea and bacteria in Baltic Sea sediments along a eutrophication gradient. Community profile analysis of 16S rRNA genes using terminal restriction length po ..."
Abstract
- Add to MetaCart
(Show Context)
This thesis focuses on microbial community structures and their functions in Baltic Sea sediments. First we investigated the distribution of archaea and bacteria in Baltic Sea sediments along a eutrophication gradient. Community profile analysis of 16S rRNA genes using terminal restriction length polymorphism (T-RFLP) indicated that archaeal and bacterial communities were spatially heterogeneous. By employing statistical ordination methods we observed that archaea and bacteria were structured and impacted differently by environmental parameters that were significantly linked to eutrophication. In a separate study, we analyzed bacterial communities at a different site in the Baltic Sea that was heavily contaminated with polyaromatic hydrocarbons (PAHs) and several other pollutants. Sediment samples were collected before and after remediation by dredging in two consecutive years. A polyphasic experimental approach was used to assess growing bacteria and degradation genes in the sediments. The bacterial communities were significantly different before and after dredging of the sediment. Several isolates collected from contaminated sediments showed an intrinsic capacity for degradation of phenanthrene (a PAH model compound). Quantititative real-time PCR was used to monitor the abundance of degradation genes in sediment microcosms spiked with phenanthrene. Although both xylE and phnAc genes increased in abundance in the microcosms, the isolates only carried phnAc genes. Isolates with closest 16S rRNA gene sequence matches to Exigobacterium oxidotolerans, a Pseudomonas sp. and a Gammaproteobacterium were identified by all approaches used as growing bacteria that are capable of phenanthrene degradation. These isolates were assigned species and strain
