|
|
|
| Registros recuperados: 47 | |
|
|
| Piriou, Jean-yves; Coic, Daniel; Merceron, Michel. |
| The coastal marsh of Kervigen is located near by the bay of Douarnenez and its 22 hectares are almost entirely covered by reeds. An experiment was there carried out to assess the nitrogen flux depletion of a small stream, the Kerharo. That one has a 45 km 2 mostly agricultural drainage basin. Due to its nitrate loadings to the next sandy beach, it feeds a green algae (Ulva) proliferation. In order to control its nitrogen fluxes, the stream was partly diverted through a part of the marsh (9 ha), before it was allowed to go back to the main bed. Thus a collapsible weir was set up during several springs and summers, i.e. the growing period of Ulva. The nitrate stripping off the going through flux is within a 30 to 90 % range,that is important (175 kg N03... |
| Tipo: Text |
Palavras-chave: Algae; Nitrogen; Ulva; Nitrate depletion; Costal marsh; Algue; Azote; Ulva; Abattement de nitrate; Marais côtier. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/rapport-64.pdf |
| |
|
| |
|
|
| Sauriau, Pierre-guy; Merceron, Michel; Goulletquer, Philippe. |
| Marine fish farming is fairly recent in France and it is still in the process of being developed. On the Atlantic and Channel coasts, it deals mainly with Atlantic salmon (Salma salar), fario trout (Salmonella faria) with l,400 t in 1991, and turbot (Scophthalmus maximus) with 600 t. In Gravelmes a bass (Dicentrarchus labrax) and bream (Sparus auratus) farm (1,000 t) uses water which is heated (Mediterranean production for these two species is around 2,000 t). Although these figures are low compared to French shellfish farming (200,000 t) and foreign fish farms (150,000 t in Norway, for example), they are growing. |
| Tipo: Text |
Palavras-chave: Biocénoses; Conchyliculture; Algoculture; Mesure de Protection; Impact non trophiques; Impact; Aquaculture littorale; Aquaculture marine. |
| Ano: 1997 |
|
| |
|
|
| Merceron, Michel. |
| At the end of July 1982, a massive number of fish and benthic invertebrates died in Vilaine Bay. The mass of fish concerned has been estimated at several tens of tonnes. The analysis of the event's conditions indicates that it was asphyxiation caused by a very pronounced depletion of dissolved oxygen in the bay's bottom waters. The appearance of toxic phytoplankton in the years that followed (Dinophysis) is aseparate topic of research by IFREMER. The most likely mechanism of that anoxia is a succession of events: (1) a first flood of Vilaine River inducing a vertical stratification of waters in Vilaine Bay, (2) an intense and superficial bloom of marine phytoplankton, (3) a stormy weather breaking up the stratification and mixing superficial... |
| Tipo: Text |
|
| Ano: 1989 |
URL: http://archimer.ifremer.fr/doc/1989/publication-2833.pdf |
| |
|
| |
|
|
| Merceron, Michel. |
| The project to enlarge the port of Le Légué at St-Brieuc required conducting an environmental impact study. This took place in 1980 and 1981 (Merceron et al). In view of the project's importance and the almost complete absence of baseline ecological studies of this area, it has been necessary to proceed with a rather extensive investigation. In this way, the field studies focused on the following aspects: hydrobiology, benthos, contaminants in the water, the sediment and living matter, Yffiniac marsh, flat fish nurseries. Overall, the impact of the Le Légué port enlargement on the marine environment of the bottom of St-Brieuc's bay seemed to be relatively minor. However a qualification was made concerning the modes of discharge of the planned basin's... |
| Tipo: Text |
|
| Ano: 1983 |
URL: http://archimer.ifremer.fr/doc/1983/rapport-2842.pdf |
| |
|
|
| Merceron, Michel. |
| De l'agglomération de CAEN à la mer, le canal double le cours de l'Orne sur une distance d'environ 14 km. Au port de OUISTREHAM le canal cominunique avec la mer par deux écluses, et en aval des écluses se trouve la confluence avec l'orne, Jusqu'au niveau des basses mers, le chenal est commun et il est encadré par deux enrochements d'axe N.S. sur une distance de 2 Km (cf. carte n°1). Les débits de l'Orne seraient respectivement de 2 m3/s en étiage, d'environ 21 m3/s en débit moyen et de 70 m3/s en crue. Ce fleuve alimente la sédimentation en matières fines qui se produit à la fois dans le chenal commun a l'aval, et dans l'avant-port soit entre le point de confluence et les écluses. La présente étude (carte n°2) porte sur : - la zone de sédimentation... |
| Tipo: Text |
|
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/00106/21684/19263.pdf |
| |
|
|
| Merceron, Michel; Gaffet, Jean-dominique. |
| Current recordings were performed near the middle of the great breakwater of Cherbourg ("Grande Digue", inner side) during two months of the 1993 summer. The data show that, in this site, the currents drive mostly westwards. They are driving eastwards only during the first half of flood. In the tidal cycle, there is only one current slack, at law tide. The most important velocities are observed during the high tides : 0.5 to 0.6 m.s-1• The fish net pens, which are located there, tend to speed up the undemeath currents and, thus, contribute to scatter the farm effluents. The temperature and salinity records are also displayed. _ |
| Tipo: Text |
Palavras-chave: Courant; Cage; Élevage; Poisson; Cherbourg; Current; Net pen; Farm; Fish; Cherbourg. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00082/19330/16924.pdf |
| |
|
| |
|
| |
|
|
| Merceron, Michel; Manaud, Francois; Guillaud, Jean-francois; Monbet, Yves. |
| The commercial port of the city of St-Brieuc currently has a limited capacity. It is only accessible for low-tonnage ships, and for this reason, cargo is not allowed, which is a contributing factor to its current traffic being limited to 450,000 tonnes per year. A significant silting-up of the port is diminishing even more its potential for accepting ships. Its future seems, therefore, threatened. Several studies conducted by the Côtes-du-Nord Chamber of Commerce and Industry have concluded that it is necessary to develop a port with greater capacity, which would stimulate the regional economy. Cargo traffic would then reach 1 million tonnes per year, and St-Brieuc would be accessible to heavier-tonnage coasters and would then follow the current growth of... |
| Tipo: Text |
|
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/rapport-2835.pdf |
| |
|
|
| Merceron, Michel. |
| The Frêt Pond at Crozon (Finistère) occupies the southwest part of Frêt's cove in Brest's harbour (fig. 1). This 18-hectare pond was isolated from the harbour by the natural accumulation of a mound of pebbles, which was reinforced by rocks so that it could support the D 155 road. At the free end of this mound, a tide mill had been built in the past, and it is through its release channel that water exchanges currently take place between the Frêt pond and Brest's harbour. The pond's catchment area occupies a surface area of 2.70 km2, of which 1.8 km2 are being farmed and 0.5 are forest area (fig. 1). The average flow over the year is estimated at 58 l/s based on a specific flow of 21.4 l/s/km2. It is therefore about 1.8 million cubic metres of fresh water... |
| Tipo: Text |
|
| Ano: 1985 |
URL: http://archimer.ifremer.fr/doc/1985/rapport-2649.pdf |
| |
|
|
| Kempf, Marc; Jacq, E; Le Guellec, C; Merceron, Michel; Monfort, Patrick; Nezan, Elisabeth; Ryckaert, Mireille. |
| This document presents a year-long (1994) environmental study conducted on a site of intensive farming of salmonids (mainly fario trout) in Camaret Bay. A set of parameters were considered for the body of water and the sea bed (flow patterns, hydrology, sedimentology, biology, chemistry) and complemented by video observations. The study concluded that there was a measurable effect from the farm in its current configuration, but that the impact was of a very limited intensity and scope that did not affect the environment in a substantial way. It is recommended that production growth be accompanied by a minimum amount of environmental assessment. |
| Tipo: Text |
Palavras-chave: Bretagne; Truite fario; Salmonidés; Environnement; Pisciculture marine. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/1995/rapport-2834.pdf |
| |
|
| |
|
|
| Merceron, Michel; Bentley, Daniel; Le Grand, Jacqueline; Lamort-datin, Laure; Kempf, Marc. |
| The environmental impact of a brown trout farm located in the Grande Rade de Cherbourg (Normandy) is reported. During observations the fish stock evolved within the range of 140 to 350 metric tons. Farm influence was researched on water column through hydrochemistry, phytoplankton, faecal bacteria and, on bottom, through grain size, organic matter, metals, macrobenthos. This report only deals with water column. Except ammonia, no hydrological parameter seems to be affected, even near to the net pens. Phytoplankton and coliform bacteria were not altered. An extra concentration of ammonia was detected at some tens meters from the raft, with favourable conditions. But generally it was impossible to observe it unless close to the farming structure, downward... |
| Tipo: Text |
Palavras-chave: Channel; Current; Faecal bacteria; Phytoplankton; Hydrology; Impact; Salmonid; Fish farm; Manche; Courant; Bactéries fécales; Phytoplancton; Hydrologie; Impact; Salmonidé; Aquaculture. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/rapport-3342.pdf |
| |
|
|
| Kempf, Marc; Cadour, Gwenael; Jeanneret, Hélène; Mear, Yan; Miramand, Pierre; Merceron, Michel. |
| This document is a result of an environmental impact study carried out between 1993 and 1995 on the site of a marine trout culture located in the Harbour of Cherbourg, France. It deals with the solid waste of the farm and concems deposition rate, sediment analysis and chemistry (fine fraction < 63 ~m, organic matter, carbon, nitrogen, copper and zinc), bottom living organisms and underwater video monitoring. The impact observed is very moderate and localised. This is mainly due to the strong d)'TIamics and flushing rate of the site. A seperate volume of the same study deals with dissolved waste and concems the water mass (volume 1 : water and pelagos). (Not controlled OCR) |
| Tipo: Text |
Palavras-chave: Rade de Cherbourg; Étude biosédimentaire; Impact; Salmoniculture marine; France; Cherbourg; Benthos; Sediment; Environmental impact; Trout; Marine fish farming. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/rapport-3349.pdf |
| |
|
| |
|
| |
|
|
| Merceron, Michel; Antoine, Virginie; Auby, Isabelle; Morand, P. |
| Ulva spp., the algae most responsible for green tides in Brittany (France), are found on the foreshore and in the most beachward wave area (MBWA) of many bays during green tide phenomena. These algae have recently been seen drifting at greater depths (reaching -20 m). In view of the significant quantities of algae found at these depths, and the less favorable conditions for algal growth than in the intertidal zone, we attempted to determine if they could grow there. For that, during their maximum growth period (from May to July), algae were picked up at three stations located on the foreshore, in the MBWA and in the subtidal (deep) zones of the Bay of Douarnenez, and their nitrogen, carbon and chlorophyll a+b contents were determined, and their... |
| Tipo: Text |
Palavras-chave: Nutrients; Irradiance; Photosynthesis; Ulva sp.; Algal blooms; Eutrophication. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3527.pdf |
| |
|
| |
| Registros recuperados: 47 | |
|
|
|
