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| Lazar, Cassandre Sara; L'Haridon, Stephane; Pignet, Patricia; Toffin, Laurent. |
| Microbial mats in marine cold seeps are known to be associated with ascending sulfide- and methane-rich fluids. Hence, they could be visible indicators of anaerobic oxidation of methane (AOM) and methane cycling processes in underlying sediments. The Napoli mud volcano is situated in the Olimpi Area that lies on saline deposits; from there, brine fluids migrate upward to the seafloor. Sediments associated with a brine pool and microbial orange mats of the Napoli mud volcano were recovered during the Medeco cruise. Based on analysis of RNA-derived sequences, the "active" archaeal community was composed of many uncultured lineages, such as rice cluster V or marine benthic group D. Function methyl coenzyme M reductase (mcrA) genes were affiliated with the... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14589/12126.pdf |
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| 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 |
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| Lazar, Cassandre Sara; Parkes, R. John; Cragg, Barry A.; L Haridon, Stephane; Toffin, Laurent. |
| Submarine mud volcanoes are a significant source of methane to the atmosphere. The Napoli mud volcano, situated in the brine-impacted Olimpi Area of the Eastern Mediterranean Sea, emits mainly biogenic methane particularly at the centre of the mud volcano. Temperature gradients support the suggestion that Napoli is a cold mud volcano with moderate fluid flow rates. Biogeochemical and molecular genetic analyses were carried out to assess the methanogenic activity rates, pathways and diversity in the hypersaline sediments of the centre of the Napoli mud volcano. Methylotrophic methanogenesis was the only significant methanogenic pathway in the shallow sediments (0-40 cm) but was also measured throughout the sediment core, confirming that methylotrophic... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15426/18003.pdf |
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