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Schmidt, Sabine; Gonzalez, Jean-louis; Lecroart, Pascal; Tronczynski, Jacek; Billy, Isabelle; Jouanneau, Jean-marie. |
Quantifier les processus de remaniement sédimentaire procure une vision nouvelle du fonctionnement des écosystèmes benthiques de l'étang de Thau, lieu d'une importante production ostréicole. Afin d'évaluer les taux de bioturbation des sédiments de surface, des profils de deux traceurs radioactifs, le béryllium 7Be (T1/2 = 53 jours) et le thorium 234Th (T1/2 = 24.1 jours) ont été mesurés à partir de carottes sédimentaires prélevées entre décembre 2001 et décembre 2006. La sélection de plusieurs sites a permis de couvrir la diversité de l'étang de Thau : C4, T10, et T11 dans le bassin central, C5, T7 et T8 au niveau des secteurs ostréicoles, T2 et T4 à l'ouest du bassin, et T12 à l'est près de la zone industrielle. Le 234Th en excès (234Thxs ; i.e. apporté... |
Tipo: Text |
Palavras-chave: Mediterranean Lagoon; Radionuclides; Biodeposition; Sedimentation. |
Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2584.pdf |
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Couturier, Christine; Rouault, Alice; Mckenzie, David; Galois, Robert; Robert, Serge; Joassard, Lucette; Claireaux, Guy. |
The French Atlantic coast contains large highly productive intertidal mudflats that are colonised by juveniles of numerous flatfish species, including the common sole (Solea solea, L.). These ecosystems are also heavily exploited by the shellfish farming industry. Intensive bivalve culture is associated with substantial biodeposition (1-6 t-dw ha(-1) day(-1)), which directly or indirectly contributes to increase exopolysaccharide (EPS) concentrations at the interface between water column and seabed. EPS are long-chain molecules organised into colloids, which influence rheological properties of water, particularly viscosity. Increased water viscosity had consequences for ventilatory activity of juvenile flatfish, whereby the minimal pressure required to... |
Tipo: Text |
Palavras-chave: EPS; Hypoxia; Metabolism; Water viscosity; Biodeposition; Solea solea. |
Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2801.pdf |
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Pouvreau, Stephane; Bodoy, Alain; Buestel, Dominique. |
In situ clearance rate (CR) and biodeposition of the black pearl oyster, Pinctada margaritifera, were followed during several field experiments from 1996 to 1998 in the lagoon of Takapoto. Serial measurements of total particulate matter (TPM, mg l(-1)), particulate inorganic matter (PLM, mg l(-1)), and particulate organic matter (POM, mg l(-1)) were related to meteorological conditions, especially wind speed. As a general case, POM and PLM increased with wind speed. Nevertheless, PLM increased faster than POM so that the organic content (OC, %) of the TPM decreased progressively when wind speed increased. These TPM variations induced direct changes in feeding processes of P. margaritifera. CR (l h(-1)) averaged 22 l h(-1) for a pearl oyster of 1 g dry... |
Tipo: Text |
Palavras-chave: Biodeposition; Clearance rate; Seston; Filter feedings behaviour; Tropical lagoon; Tropical bivalve. |
Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-382.pdf |
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