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| Merceron, Michel. |
| The 1998 survey of green tides on the Brittany coast was performed in the same way as that of 1997 in order to allow comparison. 11 includes an inventory ofail the concerned sites, and a precise assessment ofthirteen ofthem, the most loaded. On these ones, nitrogen fluxes were surveyed during the critical period, and the green seaweed stock on the beach and in the first waves was quantified. The climatic conditions were opposite between the two years, very dry in spring and summer 1997, and wet in 1998. The irradiance contrast was inverse, and less pronounced. The nitrate contents and mostly the flows were more important in 1998. They generated nitrogen fluxes about 3.3 times those of 1997. The total number of sites concerned in 1998 is clearly higher than... |
| Tipo: Text |
Palavras-chave: Bretagne; Nitrate; Prolifération; Ulve; Eutrophisation; Brittany; Nitrate; Proliferation; Ulva; Eutrophication. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/rapport-2665.pdf |
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| Merceron, Michel. |
| On tens of sandy beaches of Brittany, a green seaweed (Ulva) blooms during spring and summer. In the sites where the proliferation is the most important, the total biomass amounted to 20 000 t of wet weight in 1997, at the time of maximum. These "green tides" occur every year in nearly the same locations. They have a very harmful impact on local tourism. In many communes, beached and rotting algae are collected and dumped (43 000 m 3 as a whole in 1997). The main development of biomass takes place between the surf zone and the bare sand.The outbreak requires three coexisting conditions : 1) a sandy beach gently sloping, 2) a weak residual current (i.e. once the tidal back and forth movement has been filtered), 3) a nitrogen loading, even moderate (ammonium... |
| Tipo: Text |
Palavras-chave: Brittany; Eutrophication; Proliferation; Ulva; Marine algae; Bretagne; Eutrophisation; Prolifération; Ulves; Algues marines. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/acte-46.pdf |
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| Brienne, Henri. |
| Mytilicola intestinalis Steuer habite les moules du Pertuis Breton. Les premiers exemplaires ont été décelés en janvier 1960, dans un lot de moules provenant de bouchots construits sur les vases de Marsilly. Il semble que l'introduction de ce copépode soit récente, bien que la mortalité constatée aux environs de 1930 puisse être protée au compte de mytilicola. Nous avons pensé qu'il serait intéressant de publier les résultats des recherches effectuées depuis l'apparition du parasite et de faire connaître les dispositions qui ont été prises pour limiter sa propagation et assurer la production à venir des moules. Cette étude a porté sur les moules de culture-bouchots de la baie de l'Aiguillon et sur les moules des gisements naturels. |
| Tipo: Text |
Palavras-chave: Prolifération; Infestation; Elevage moules; Mytilus edulis; Mytilicola intestinalis; Pertuis Breton. |
| Ano: 1964 |
URL: http://archimer.ifremer.fr/doc/00135/24639/22668.pdf |
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| Merceron, Michel. |
| The yearly study of Ulva in Brittany aims at building a time series of its proliferations and corresponding nutrient loadings. The goal is to detect results of wilful loading reductions, and to distinguish them from natural variations. This first actually quantified study is the starting bench-mark of the process. Forty-five concerned sites were listed in 1997. They are nearly the same as in 1988, 1991 and 1994 (previous rough census). The Côtes d'Armor and then the Finistère are the most affected departments. The Morbihan is less and file et Vilaine not at all. Ulva biomass was precisely quantified in about fifteen locations during the growing season, along with nitrogen loadings of local streams (mostly nitrate). The fluxes of nitrogen - the limiting... |
| Tipo: Text |
Palavras-chave: Bretagne; Nitrate; Prolifération; Ulve; Eutrophisation; Brittany; Nitrate; Proliferation; Ulva; Eutrophication. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/1998/rapport-1580.pdf |
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