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| Roussel, Erwan; Cragg, Barry A.; Webster, Gordon; Sass, Henrik; Tang, Xiaohong; Williams, Angharad S.; Gorra, Roberta; Weightman, Andrew J.; Parkes, R. John. |
| The impact of temperature (0 - 80°C) on anaerobic biogeochemical processes and prokaryotic communities in marine sediments (tidal flat) was investigated in slurries for up to 100 days. Temperature had a non-linear effect on biogeochemistry and prokaryotes with rapid changes over small temperature intervals. Some activities (e.g. methanogenesis) had multiple “windows” within a large temperature range (~10 - 80°C). Others, including acetate oxidation, had maximum activities within a temperature zone, which varied with electron acceptor (metal oxide [up to ~34°C] and sulphate [up to ~50°C]). Substrates for sulphate reduction changed from predominantly acetate below, and H2 above, a 43°C critical temperature; along with changes in activation energies and types... |
| Tipo: Text |
Palavras-chave: Sediment; Temperature; Anaerobic processes; Chemoorganotrophic; Chemolithotrophic; Mineralisation; Sulphate reduction; Methanogenesis; Acetogenesis. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00273/38464/36883.pdf |
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| Vigneron, Adrien; L Haridon, Stephane; Godfroy, Anne; Roussel, Erwan; Cragg, Barry A.; Parkes, R. John; Toffin, Laurent. |
| In the Sonora Margin cold seep ecosystems (Gulf of California), sediments underlying microbial mats harbor high biogenic methane concentrations, fueling various microbial communities, such as abundant lineages of anaerobic methanotrophs (ANME). However, the biodiversity, distribution, and metabolism of the microorganisms producing this methane remain poorly understood. In this study, measurements of methanogenesis using radiolabeled dimethylamine, bicarbonate, and acetate showed that biogenic methane production in these sediments was mainly dominated by methylotrophic methanogenesis, while the proportion of autotrophic methanogenesis increased with depth. Congruently, methane production and methanogenic Archaea were detected in culture enrichments amended... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00256/36737/35338.pdf |
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| 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 |
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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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| Vigneron, Adrien; Cruaud, Perrine; Roussel, Erwan; Pignet, Patricia; Caprais, Jean-claude; Callac, Nolwenn; Ciobanu, Maria Cristina; Godfroy, Anne; Cragg, Barry A.; Parkes, John R.; Van Nostrand, Joy D.; He, Zhili; Zhou, Jizhong; Toffin, Laurent. |
| Subsurface sediments of the Sonora Margin (Guaymas Basin), located in proximity of active cold seep sites were explored. The taxonomic and functional diversity of bacterial and archaeal communities were investigated from 1 to 10 meters below the seafloor. Microbial community structure and abundance and distribution of dominant populations were assessed using complementary molecular approaches (Ribosomal Intergenic Spacer Analysis, 16S rRNA libraries and quantitative PCR with an extensive primers set) and correlated to comprehensive geochemical data. Moreover the metabolic potentials and functional traits of the microbial community were also identified using the GeoChip functional gene microarray and metabolic rates. The active microbial community structure... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00203/31408/29801.pdf |
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