|
|
|
| Registros recuperados: 10 | |
|
|
| Orvain, Francis; Le Hir, Pierre; Sauriau, Pierre-guy. |
| Previous studies have shown that the gastropod Hydrobia ulvae destabilizes the top layers of fine-grained sediments. This process is mediated by the formation of a "biogenic" fluff layer that includes tracks, faecal pellets and mucus. This fluff layer has been shown to be easily resuspended before general bed erosion. In order to examine how fluff layer and bed. erosion interact, flume experiments were performed with fluid sediments of varying water contents. Ten thousand snails were placed and allowed to crawl for 5 h on the sediment surface, and then the resuspended sediment mass was measured in response to step-wise shear stress increases. Two distinct erosion phases were observed: (1) initial resuspension of the fluff layer and (2) the subsequent bed... |
| Tipo: Text |
Palavras-chave: Gastropoda; Erosion sediment; Bioturbation; Cohesive sediment; Marine sediment. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-805.pdf |
| |
|
| |
|
|
| Mamindy-pajany, Yannick; Hurel, Charlotte; Geret, Florence; Galgani, Francois; Battaglia-brunet, Fabienne; Marmier, Nicolas; Romeo, Michele. |
| This work investigates arsenic mobility, bioavailability and toxicity in marine port sediments using chemical sequential extraction and laboratory toxicity tests. Sediment samples were collected from two different Mediterranean ports, one highly polluted with arsenic and other inorganic and organic pollutants (Estaque port (EST)), and the other one, less polluted, with a low arsenic content (Saint Mandrier port (SM)). Arsenic distribution in the solid phase was studied using a sequential extraction procedure specifically developed for appraising arsenic mobility in sediments. Toxicity assessment was performed on sediment elutriates, solid phases and aqueous arsenic species as single substance using the embryotoxicity test on oyster larvae (Crassostrea... |
| Tipo: Text |
Palavras-chave: Arsenic speciation; Chemical sequential extraction; Embryo-toxicity test; Marine sediment; Microtox toxicity test; Pollutant bioavailability. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00127/23820/22580.pdf |
| |
|
|
| Yanagawa, Katsunori; Tani, Atsushi; Yamamoto, Naoya; Hachikubo, Akihiro; Kano, Akihiro; Matsumoto, Ryo; Suzuki, Yohey. |
| The biological flux and lifetime of methanol in anoxic marine sediments are largely unknown. We herein reported, for the first time, quantitative methanol removal rates in subsurface sediments. Anaerobic incubation experiments with radiotracers showed high rates of microbial methanol consumption. Notably, methanol oxidation to CO2 surpassed methanol assimilation and methanogenesis from CO2/H2 and methanol. Nevertheless, a significant decrease in methanol was not observed after the incubation, and this was attributed to the microbial production of methanol in parallel with its consumption. These results suggest that microbial reactions play an important role in the sources and sinks of methanol in subseafloor sediments. |
| Tipo: Text |
Palavras-chave: Methanol consumption; Methanol production; Marine sediment. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00342/45319/44777.pdf |
| |
|
|
| Aoki, Kaori. |
| A tephra layer with normal grading in the sub‐bottom depth interval 119–122 cm in marine core SO202‐27‐6 was collected on Patton Seamount in the northeast North Pacific Ocean. Based on the geochemistry of volcanic glass shards determined by a wavelength dispersive electron probe micro‐analyser and an X‐ray fluorescence analyser, this layer is correlated to the Dawson tephra, a widespread late Pleistocene time marker tephra in Alaska and the Yukon. The age of the Dawson tephra in the core is 29.03 ± 0.178 ka (1 sigma) based on a published age model. The Dawson tephra is revealed to have been deposited in the transition from marine isotope stage 3 to 2, i.e. the last stage of Heinrich Stadial 3 derived from the ice‐rafted debris signal. According to the... |
| Tipo: Text |
Palavras-chave: Dawson tephra; Heinrich Stadial; Late Pleistocene; Marine sediment; MIS3; 2. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00598/71056/69371.pdf |
| |
|
| |
|
|
| Sultan, Nabil; Cochonat, Pierre; Bourillet, Jean-francois; Cayocca, Florence. |
| This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried... |
| Tipo: Text |
Palavras-chave: Shear strength; Slope stability; Safety factor; Marine sediment; Finite element; Finite difference; Failure. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-698.pdf |
| |
|
|
| Pommepuy, Monique; Hervio Heath, Dominique; Caprais, Marie-paule; Gourmelon, Michele; Le Saux, Jean-claude; Le Guyader, Soizick. |
| Introduction : "The occurrence of pathogenic microorganisms in seawater or in shellfish could exist anytime sewage from human or animal origin would be discharged to the coast" (Metcalf, 1982). According to the diseases occurring in the human population or in animals, pathogens might be present in recreational waters or in shellfish. Thus, the presence of human enteric viruses (norovirus, astrovirus, rotavirus, hepatitisAvirus (HAV)) and pathogenic bacteria (Salmonella, Listeria monocytogenes, Shiga-toxin-producing Escherichia coli (STEC), Vibrio cholerae, Vibrio parahaemolyticus, etc.) has been reported in coastal areas for a long time (Colwell, 1978; Metcalf, 1978; Melnick et al., 1979; Grimes, 1991; Bosch et al., 2001;Kong et al., 2002). These... |
| Tipo: Text |
Palavras-chave: Estimating model; Infection dose; Microorganisms; STEC; Bacteria; Virus; Fecal contamination; Pathogenic agent; Marine sediment; Estuarine water; Coastal area; Marine water. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1207.pdf |
| |
|
|
| Sultan, Nabil; Lafuerza, Sara. |
| L’excès de pression interstitielle a un effet significatif sur la stabilité des pentes sous-marines et sur la déformation des sédiments, alors sa mesure in-situ à l’équilibre est cruciale pour réaliser des évaluations exactes de la stabilité des pentes et pour dériver adéquatement les paramètres géotechniques de conception. La pression interstitielle in-situ à l’équilibre est généralement obtenue à partir de la diminution de la pression interstitielle lors d’essais en piézocône. Cependant, les plateaux et pentes sous-marins sont souvent caractérisés par l’existence de sédiments à faible perméabilité (à granulométrie fine) qui engendrent des tests de dissipation de longue durée, ce qui représente une problématique pour les coûts d’opération en mer. Ainsi,... |
| Tipo: Text |
Palavras-chave: Cavity expansion; Dissipation tests; Marine sediment; Piezoprobe; Pore-water pressure. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00198/30926/29346.pdf |
| |
|
| |
| Registros recuperados: 10 | |
|
|
|
