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| Gentilhomme, V; Raimbault, P. |
| The uptake and regeneration of four forms of nitrogen NO3-, NO2-, NH4+ and urea) have been studied, in the euphotic layer of a frontal area (Algerian current), in relation with hydrological, chemical and biological parameters. Ln this area vertical stratification is pronounced; a deep chlorophyll maximum at the bottom of the euphotic layer is present. Results show the importance of measuring urea uptake and regeneration in the study of nitrogen cycling, because this component can be regenerated as rapidly as ammonia, and is a source of nitrogen for phytoplankton. Other results show the oxidation of ammonia to nitrate in the euphotic layer, and particularly at the base of this layer. This nitrification is a source of in situ regenerated nitrate, and could... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00099/21012/18638.pdf |
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| Brylinski, J M; Lagadeuc, Y; Gentilhomme, V; Dupont, J P; Lafite, R; Dupeuble, P A; Huault, M F; Auger, Y. |
| The English Channel has a "megatidal" regime: in the Dover Strait, the tidal range varies between 3 and 9 m in neap-tide and spring-tide respectively. The tide currents are alternating and essentially parallel to the coast. Along the French coast, the fluvial supplies, distributed from the Bay of Seine to Cape Gris-Nez, generate a coastal water mass which drifts nearshore, separated from the open sea by a frontal area: this coastal flow is characterized by its freshness, turbidity, phytoplankton richness, and pollution content. Its width is only 3 to 5 miles, but because of the high concentrations of dissolved and suspended components, it is possible that the coastal flow plays an important role in the fluxes between the Eastern Channel and the North Sea. |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00268/37874/35955.pdf |
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| Boulart, C; Flament, Pierre; Gentilhomme, V; Deboudt, K; Migon, C; Lizon, F; Schapira, M; Lefebvre, Alain. |
| Wet atmospheric deposition of dissolved N, P and Si species is studied in well-mixed coastal ecosystem to evaluate its potential to stimulate photosynthetic activities in nutrient-depleted conditions. Our results show that, during spring, seawater is greatly depleted in major nutrients: Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP) and Silicic acid (Si), in parallel with an increase of phytoplanktonic biomass. In spring (March-May) and summer (June-September), wet atmospheric deposition is the predominant source (> 60%, relative to riverine contribution) for nitrates and ammonium inputs to this N-limited coastal ecosystem. During winter (October-February), riverine inputs of DIN predominate (> 80%) and are annually the most... |
| Tipo: Text |
Palavras-chave: Strait of Dover; Nutrient cycles; River plumes; Atmospheric deposition; Coastal zone; Primary production. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2007.pdf |
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