Consulta: subjectFacets:"McrA"
Registros recuperados: 4
Data/hora: 06/06/2024 09:20:17

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

Archaeal Methane Cycling Communities Associated with Gassy Subsurface Sediments of Marennes-Oleron Bay (France)
Provedor de dados: 5
Autores: Roussel, Erwan; Sauvadet, Anne Laure; Allard, Jonathan; Chaduteau, Carine; Richard, Pierre; Cambon Bonavita, Marie-anne; Chaumillon, Eric.
In Marennes-Oleron Bay, a macro-tidal bay located on the French Atlantic coast, kilometer-scale acoustic turbidity reveals an accumulation of free gas in the sediment. Large concentrations of organic matter and rapid sedimentation rates provide ideal settings for biogenic methane cycling. We integrate seismic, sedimentologic, biogeochemical and molecular genetic approaches to determine whether microbial methane cycling is involved in this process. Here we show that the acoustic turbidity upper boundary matched with X-ray facies displaying fissures with the highest methane concentrations, demonstrating the existence of methane bubbles in the sediment. 16S rRNA and mcrA gene clone libraries were dominated by sequences affiliated to the three known ANME...
Tipo: Text
Palavras-chave: Sediment; Methane; McrA; 16S rRNA; Archaea.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6165.pdf

Methanogenic activity and diversity in the centre of the Amsterdam Mud Volcano, Eastern Mediterranean Sea
Provedor de dados: 5
Autores: Lazar, Cassandre; Parkes, R. John; Cragg, Barry A.; L'Haridon, Stephane; Toffin, Laurent.
Marine mud volcanoes are geological structures emitting large amounts of methane from their active centres. The Amsterdam mud volcano (AMV), located in the Anaximander Mountains south of Turkey, is characterized by intense active methane seepage produced in part by methanogens. To date, information about the diversity or the metabolic pathways used by the methanogens in active centres of marine mud volcanoes is limited. 14C-radiotracer measurements showed that methylamines/methanol, H2/CO2 and acetate were used for methanogenesis in the AMV. Methylotrophic methanogenesis was measured all along the sediment core, Methanosarcinales affiliated sequences were detected using archaeal 16S PCR-DGGE and mcrA gene libraries, and enrichments of methanogens showed...
Tipo: Text
Palavras-chave: Methanogenesis; McrA; Archaea.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00087/19795/17538.pdf

Diversité et activité des communautés microbiennes dans des sédiments marins associés aux émissions de fluides froids
Provedor de dados: 5
Autores: Lazar, Cassandre Sara.
A large portion of the greenhouse gas methane on Earth is trapped in marine sediments. However, little methane actually reaches the hydrsphere and the atmosphere, because it is efficiently consumed by anaerobic methane-oxidizing Archaea (ANME). This methane is mainly biogenic in marine sédiments, and is produced by methanogenic Archaea. Methane ascends from deep sources to the seabed, in cold seep sites of continental margins. In order to study microbial community diversity in cold seeps, and to determine geochemical factors that control these microbial communities, we compared four geochemically and geologically distinct sites. In this work, molecular tools (PCR, RT-PCR, DGGE, cloning) as well as genetic markers (16S rRNA, mcrA, dsrB) were employed, to...
Tipo: Text
Palavras-chave: Diversité moléculaire; Archaea; Méthanogène; ANME; McrA; DsrB; DGGE; Volcan de boue; Pockmark; Saumures; Fluides froids; Méthane; Mer de Norvège; Mer Méditerranée; Sédiments.; Molecular diversity; Archaea; Methanogen; ANME; McrA; DsrB; DGGE; Mud volcano; Pockmark; Brines; Cold seep; Methane; Norwegian Sea; Mediterranean Sea; Sediments.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00031/14250/11534.pdf