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| Jacobs, Walter; Le Hir, Pierre; Van Kesteren, Walther; Cann, Philippe. |
| Results of a large number of erosion tests on artificially generated and relatively dense sand-mud mixtures are presented. Soil sample compositions are varied concerning clay-silt and sand-silt ratio, and clay mineralogy. The experimental set-up consists of a re-circulating small-scale rectangular erosion flume with unidirectional flow conditions. The erosion threshold and erosion rate are studied through step by step increasing the flow rate during a test. Results clearly indicate time-decreasing erosion during which individual flocs are randomly eroded, and time-independent (steady) erosion during which both sand and mud particles are continuously and uniformly eroded. These two erosion types appear to be floc and surface erosion, respectively... |
| Tipo: Text |
Palavras-chave: Erosion; Sand-mud mixtures; Clay; Sediment structure; Critical shear stress; Strength. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15252/12678.pdf |
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| Hamon, Dominique; Blanchard, Michel; Houlgatte, Eric; Blanchet, Aline; Gaffet, Jean-dominique; Cugier, Philippe; Menesguen, Alain; Bassoullet, Philippe; Cann, Philippe; Domalain, David; Haubois, Anne-gaelle. |
| La crépidule (Crepidula fornicata), mollusque gastéropode de la famille des Calyptraeidés, originaire de la côte atlantique d'Amérique du nord, a été introduite accidentellement sur le littoral français en plusieurs étapes (Blanchard, 1995, 1997). La plus importante d'entre elles, au début des années 70, est liée à l'importation massive de l'huître japonaise (Crassostrea gigas), en remplacement de l'huître portugaise (Crassostrea angulata) décimée par une épizootie. Cette espèce opportuniste a notamment proliféré au voisinage des principaux bassins ostréicoles de la Manche et de l'Atlantique. C'est en particulier le cas des zones conchylicoles infralittorales du golfe normano-breton où des évaluations de stocks font état de plusieurs centaines de milliers... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00032/14295/11574.pdf |
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| Loyer, Sophie; Lampert, Luis; Menesguen, Alain; Cann, Philippe; Labasque, Thierry. |
| The French Atlantic shelf is Subjected to strong anthropic influences (urban, industrial and agricultural discharges) of two main rivers (Loire and Gironde). The extension and consequences of these continental loadings for the nutrient and chlorophyll distribution have never been studied before oil the Bay of Biscay continental shelf as a whole. We present the first synoptic view of the nutrient distribution and evolution oil the French Atlantic shelf. Nutrient concentrations of the surface layer were Studied during four cruises in April, June, September 1999 and March 2000. Until June, the freshwater inputs induce a nitrate gradient from river months to offshore waters in the vicinity of the 100 m isobath. The Redfield's ratio Study highlights the nitrate... |
| Tipo: Text |
Palavras-chave: Nutrients; River inputs; Coastal water; Bay of Biscay. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3956.pdf |
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| Verney, Romaric; Jany, Cassandre; Thouvenin, Benedicte; Pairaud, Ivane; Vousdoukas, Michalis I.; Pinazo, Christel; Ardhuin, Fabrice; Cann, Philippe. |
| Human pressures on ecosystems have increased significantly over the last decades, and especially Mediterranean coasts are strongly impacted by the development of big cities and industrialized area, such as the Bay of Marseille. Prior to any investigations on ecological or contamination impacts, it was necessary to understand sediment dynamics and its response to natural extreme events such as storm or heavy rainfall events. In situ observations were dedicated to understand the behavior of bed sediments, and their spatial distribution. A benthic station was deployed for three months to observe the impact of extreme events on hydrodynamics and sediment dynamics in a critical zone of the study area. These measurementswere used to calibrate and validate the... |
| Tipo: Text |
Palavras-chave: Sediment dynamics; Large coastal cities; Urban pressure; Extreme events; Wave; Rainfall; Marseille. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00204/31515/29929.pdf |
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| Cayocca, Florence; Bassoullet, Philippe; Le Hir, Pierre; Jestin, Herve; Cann, Philippe. |
| Mont Saint Michel Bay is a 30 km wide bay located on the French side of the English Channel. The tidal range reaches 14 m during spring tides, which leads, along with the gentle slope of the bathymetry, to a tidal flat up to 11 km wide. The sedimentary coverage exhibits strong longshore and cross-shore gradients, with purely muddy environments to the west of the domain, and pure sands to the east, where the natural channels of three incoming rivers induce rapid morphological changes. The contributions of tides and waves to sedimentary processes are analysed by means of numerical modelling and results of field observations. Maximum tidal bottom shear stresses are shown to account for the sediment distribution throughout the bay, while the longshore gradient... |
| Tipo: Text |
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| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6278.pdf |
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| Orvain, Francis; Sauriau, Pierre-guy; Le Hir, Pierre; Guillou, Gael; Cann, Philippe; Paillard, Michel. |
| A portable erosion device (ERIS) was deployed in November 2000 and May 2001 to investigate the spatio-temporal variation of fine-grained sediment erosion over a transect on the intertidal mudflats of Marennes-Oleron Bay, western France. The objective was to relate changes in bed erodability over diurnal emersion periods to bioturbation, rapid changes in sediment characteristics, and microphytobenthos biomass. Macrofaunal assemblages were dominated by the bivalve, Scrobicularia plana, on the upper mudflat, and by the gastropod, Hydrobia ulvae. on the middle mudflat. A power relationship was obtained where tau(cr) was plotted as a function of sediment density. Results from the upper part of the mudflat deviated from this relationship due to bioturbation by... |
| Tipo: Text |
Palavras-chave: EPS; Microphytobenthos; Erodability; Intertidal mudflat; Sediment; Scrobicularia plana; Hydrobia ulvae; Bioturbation; Resuspension; Eris. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3779.pdf |
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