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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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Bernard, Guillaume; Duchene, Jean-claude; Romero-ramirez, Alicia; Lecroart, Pascal; Maire, Olivier; Ciutat, Aurelie; Deflandre, Bruno; Gremare, Antoine. |
The effects of temperature and food addition on particle mixing in the deposit-feeding bivalve Abra alba were assessed using an experimental approach allowing for the tracking of individual fluorescent particle (luminophore) displacements. This allowed for the computations of vertical profiles of a set of parameters describing particle mixing. The frequency of luminophore displacements (jumps) was assessed through the measurement of both waiting times (i.e., the time lapses between two consecutive jumps of the same luminophore) and normalized numbers of jumps (i.e., the numbers of jumps detected in a given area divided by the number of luminophores in this area). Jump characteristics included the direction, duration and length of each jump. Particle... |
Tipo: Text |
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Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00375/48615/49432.pdf |
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Deborde, Jonathan; Anschutz, Pierre; Chaillou, Gwenaelle; Etcheber, Henri; Commarieu, Marc-vincent; Lecroart, Pascal; Abril, Gwenael. |
Suspended particles and surface waters were collected in the Gironde estuary (southwestern France) along the salinity gradient. Dissolved inorganic phosphorus (DIP) was analyzed in the filtered surface waters. The suspended particles were sequentially leached to determine five fractions of phosphorus: exchangeable or loosely sorbed P, reactive Fe-bound P, refractory Fe oxide-bound P, P associated with apatite and carbonates, and organic P. Experiments were conducted to determine the effects of temperature, salinity, and DIP concentration on phosphorus sorption/desorption processes. The concentration and distribution of particulate phosphorus was homogeneous along the salinity gradient of the estuary, whereas it was variable in time and space in the... |
Tipo: Text |
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Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00603/71538/69943.pdf |
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