Data/hora: 07/06/2024 03:47:20

Provedor de dados: | 5
País: | France
Título: | Synthèse des données sédimentaires du banc de Lamouroux (baie de Marennes-Oléron). Travaux bathymétriques et sédimentologiques
Autores: | Robert, Serge; Geairon, Philippe.
Data: | 2013-03
Ano: | 2013
Resumo: | Because of its significant geographic position within the Bay of Marennes-Oleron and its economic interest due to the successful management of the settled oyster beds at a late stage prior to shellfish commercialization, the very productive Lamouroux bench was considered a decade as a workshop zone by Ifremer. Different works were run, among them two ones in sedimentary field whose the common goal was to better understand phenomena of silting of the oyster beds. The first study, consisting of annual or biennial bathymetric surveys during 2005-2011 period, was used to characterize : (i) the bathymetric evolution of the bench under oyster influence ; (ii) the resulting sediment budget and (iii) the consequences of the bottom raising for access to parks. The second study, composed of high frequency measures and sedimentological analyses of the bottom and the interface during 2007-2008 period, has led to different results concerning : (i) the characterization of elevation changes in the interface based on the local hydrodynamic factors and the presence of oyster tables; (ii) the highlighting of seasonal variations of the textural composition of surface sediment and the determination of these changes origin ; (iii), the assessment of the sediment budget from deposits generated by oysters and their part in overall sedimentation of bench.  The present synthesis establishes that the resultant sediment dynamics on the study area is multifactorial and characterized by phenomena of erosion and/or deposition of formations on the Lamouroux bench. The bottom elevation changes lead average rises of approximately threequarters of a meter height in 6 years. The dynamic processes are correlated with some complex sedimentological compositions and the deposits are characterized by their multi-year morphological change, showing that the sediment dynamic main cause is not oyster biodeposition, but local roughness : so, wave hydrodynamics has a function of freshly deposited sediments "hunting", especially in storm period, and controls the movements of the sandy interface, except operating times.  At last, this study provides professionals information on the oyster beds up/off covering state in function of geographical location of them, tidal coefficients and bottoms bathymetric changes.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/00118/22936/22162.pdf
Relação: | http://archimer.ifremer.fr/doc/00118/22936/
Formato: | application/pdf
Fonte: | 2013 Ifremer