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| Dessandier, Pierre-antoine; Borrelli, Chiara; Kalenitchenko, Dimitri; Panieri, Giuliana. |
| Benthic foraminifera have been widely used as proxy for paleo-methane emissions, mainly based on their stable isotopic signature. In cold seeps, the ecology of these organisms remains uncertain, in particular their ability to thrive during active phases of seepage. In this study, we evaluate the benthic foraminiferal response to methane seepage in Arctic sediments. We do so by examining living and dead benthic foraminiferal assemblages (>63 mu m) of 11 push cores collected in two of the most active pockmarks (Lunde and Lomvi) along Vestnesa Ridge, offshore western Svalbard. Benthic foraminiferal assemblages are interpreted in the context of sediment geochemistry, seafloor images, and pore water analyses, which are used to characterize the different... |
| Tipo: Text |
Palavras-chave: Benthic foraminiferal assemblages; Methane advection; Methane diffusion; Arctic Ocean; Microbial mats. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00667/77894/80079.pdf |
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| Dessandier, Pierre-antoine; Borrelli, Chiara; Yao, Haoyi; Sauer, Simone; Hong, Wei-li; Panieri, Giuliana. |
| Paleoceanographic investigations in the Arctic and north Atlantic are crucial to understanding past and current climate change, in particular considering amounts of pressure-temperature sensitive gas stored in marine sediments of the region. Many paleoceanographic studies are based on foraminiferal oxygen and carbon stable isotope compositions (δ18O, δ13C) from either planktonic specimens, benthic specimens or both. However, in seafloor regions promixal to high upward methane fluxes, such as where seafloor gas emission and shallow gas hydrate-bearing sediment occur, foraminiferal δ18O and δ13C display a wide range of values. Our study focuses on foraminiferal stable isotope signatures in shallow sediment at core sites in the Arctic and North Atlantic... |
| Tipo: Text |
Palavras-chave: Foraminiferal stable isotopes; Gas hydrates; Authigenic carbonates Arctic Ocean; North Atlantic Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00610/72215/71338.pdf |
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| Carrier, Vincent; Svenning, Mette M.; Grundger, Friederike; Niemann, Helge; Dessandier, Pierre-antoine; Panieri, Giuliana; Kalenitchenko, Dimitri. |
| Cold seeps are characterized by high biomass, which is supported by the microbial oxidation of the available methane by capable microorganisms. The carbon is subsequently transferred to higher trophic levels. South of Svalbard, five geological mounds shaped by the formation of methane gas hydrates, have been recently located. Methane gas seeping activity has been observed on four of them, and flares were primarily concentrated at their summits. At three of these mounds, and along a distance gradient from their summit to their outskirt, we investigated the eukaryotic and prokaryotic biodiversity linked to 16S and 18S rDNA. Here we show that local methane seepage and other environmental conditions did affect the microbial community structure and composition.... |
| Tipo: Text |
Palavras-chave: Arctic; Methane seeps; Prokaryotes; Methanotrophs; ANME; Sulfate-reducing bacteria; Eukaryotes; Foraminifera. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00667/77893/80077.pdf |
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