Consulta: subjectFacets:"Ultramafic"
Registros recuperados: 6
Data/hora: 01/06/2024 10:34:47

Subseafloor archaeal communities: from the surface to a deep hot biosphere?
Provedor de dados: 5
Autores: Roussel, Erwan.
The sub-seafloor biosphere may contain two thirds of Earth's total prokaryotic biomass. The large and active microbial populations buried in the sub-seafloor play a key role in global biogeochemical cycles. However, little is known about these prokaryotic communities. The depth limit of this sub-seafloor biosphere is still unreached, and elevated temperatures as well as insufficient energy sources are the likely factors limiting life at depth. Interestingly, archaeal communities with unknown physiologies and no cultured relatives seem to have a key role in deep marine sediments and hydrothermal ecosystems.  As most deep biosphere microorganisms detected so far have been extremely resistant to cultivation, molecular approaches remain to date the most...
Tipo: Text
Palavras-chave: Sediment; Hydrothermal system; Ultramafic; CM DGGE; DGGE; PmoA; DsrA; McrA; AmoA; 16SrRNA; Bacteria; Archaea; Deep biosphere; Sédiment; Écosystème hydrothermal; Ultramafique; CM DGGE; DGGE; PmoA; DsrA; McrA; AmoA; 16SrRNA; Bacteria; Archaea; Biosphère profonde.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-4630.pdf

Comparison of microbial communities associated with three Atlantic ultramafic hydrothermal systems
Provedor de dados: 5
Autores: Roussel, Erwan; Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves; Querellou, Joel; Prieur, Daniel; Cambon-bonavita, Marie-anne.
The distribution of Archaea and methanogenic, methanotrophic and sulfate-reducing communities in three Atlantic ultramafic-hosted hydrothermal systems (Rainbow, Ashadze, Lost City) was compared using 16S rRNA gene and functional gene (mcrA, pmoA and dsrA) clone libraries. The overall archaeal community was diverse and heterogeneously distributed between the hydrothermal sites and the types of samples analyzed (seawater, hydrothermal fluid, chimney and sediment). The Lost City hydrothermal field, characterized by high alkaline warm fluids (pH&gt;11; T&lt;95 °C), harbored a singular archaeal diversity mostly composed of unaffiliated Methanosarcinales. The archaeal communities associated with the recently discovered Ashadze 1 site, one of the deepest active...
Tipo: Text
Palavras-chave: Archaea; Hydrothermal vent; Mid-Atlantic Ridge; 16S rRNA gene; Sediment; Ultramafic.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00067/17836/15573.pdf

Origin of organic compounds in fluids from ultramafic-hosted hydrothermal vents of the Mid-Atlantic Ridge
Provedor de dados: 5
Autores: Konn, Cécile.
Natural gas, primarily methane (CH4), is produced in substantial amounts in ultramafic-hosted hydrothermal systems. These systems could also generate oil (heavier hydrocarbons) and the first building blocks of life (prebiotic molecules). In the presence of iron bearing minerals, serpentinisation reactions generate H2. Subsequently, CH4 could be synthesised by Fischer-Tropsch Type (FTT) reaction (4H2 + CO2 -&gt; CH4 + 2H2O) which is an abiotic process. This has lead to the idea of abiotic formation of larger organic molecules. Both thermodynamics and laboratory work support this idea, yet field data have been lacking. This study focuses on determining the organic content of fluids from ultramafic-hosted hydrothermal systems from the Mid-Atlantic Ridge (MAR)...
Tipo: Text
Palavras-chave: Origin of life; Geochemistry; Hydrothermal; Ultramafic; Organic compounds; Hydrocarbons; Serpentinisation; Origine de la vie; Géochimie; Systèmes hydrothermaux; Ultrabasique; Composés organiques; Hydrocarbures; Serpentinisation.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/these-6939.pdf

Hydrocarbons and oxidized organic compounds in hydrothermal fluids from Rainbow and Lost City ultramafic-hosted vents
Provedor de dados: 5
Autores: Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Holm, N. G.; Dehairs, F.; Bouillon, S.
The first building blocks of life could be produced in ultramafic-hosted hydrothermal systems considering the large amounts of hydrogen and methane generated by serpentinisation and Fischer-Tropsch-Type synthesis, respectively, in those systems. The purpose of this study was to detect and characterise organic molecules in hydrothermal fluids from ultramafic-hosted hydrothermal systems in the Mid-Atlantic Ridge (MAR) region. During the EXOMAR cruise 2005, fluids from the Rainbow (36°14'N) and the Lost City (30°N) hydrothermal fields were collected and treated by Stir Bar Sorptive Extraction (SBSE) and Solid Phase Extraction (SPE). The extracts were analysed by Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS) and GC-MS, respectively....
Tipo: Text
Palavras-chave: Serpentinisation; Organic; Ultramafic; Hydrothermal; Origin of life.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00067/17828/15576.pdf

Expansion of the Nepenthes alata group (Nepenthaceae), Philippines, and descriptions of three new species
Provedor de dados: 16
Autores: Cheek, M.; Jebb, M.
Three new species in the Nepenthes alata group from the Philippines, Nepenthes armin, N. tboli and N. zygon, are described and assessed as threatened using the IUCN 2012 standard. The group is expanded by the inclusion of N. truncata and N. robcantleyi, previously included in the N. regiae group. A key to the nineteen species of the group is presented.
Tipo: Article / Letter to the editor
Palavras-chave: Conservation; IUCN; Mining; Nepenthes; Philippines; Taxonomy; Ultramafic.
Ano: 2014
URL: http://www.repository.naturalis.nl/record/525882

Nepenthes ultra (Nepenthaceae), a new species from Luzon, Philippines
Provedor de dados: 16
Autores: Cheek, M.; Jebb, M.
Nepenthes ultra is described from low altitude, ultramafic coastal scrub in Luzon, Philippines. It is placed in the Nepenthes alata group and is assessed as Endangered using the IUCN 2001 standard. Open cast mining and touristic development are threats to this species.
Tipo: Article / Letter to the editor
Palavras-chave: Conservation; Luzon; Nepenthes; Philippines; Ultramafic.
Ano: 2013
URL: http://www.repository.naturalis.nl/record/524739