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| Fiala, M; Delille, B; Dubreuil, C; Kopczynska, E; Leblanc, K; Morvan, J; Queguiner, B; Blain, S; Cailliau, C; Conan, P; Corvaisier, R; Denis, M; Frankignoulle, M; Oriol, L; Roy, S. |
| A mesoscale study was conducted in January and February 1999 in the Crozet Basin frontal zones (43degrees50' to 45degrees20'S, 61degrees00' to 64degrees30'E) within the southernmost and easternmost convergence area of the Antarctic Circumpolar Current (ACC) and the Agulhas Return Current (ARC). Distribution of biogeochemical parameters was strongly linked to the merged Subtropical (STF) and Subantarctic (SAF) Fronts which mark the border between the cold and less saline subantarctic waters and the warm and more saline subtropical waters. This survey took place during a post-bloom period. Chlorophyll a concentrations were low throughout the study area ranging from 0.2 mug l(-1) in the Polar Frontal Zone (PFZ) to 0.4 mug l(-1) in the Subtropical Zone (STZ).... |
| Tipo: Text |
Palavras-chave: Frontal zones; Nutrients; Biogenic silica; Chlorophyll a; PCO(2); Phytoplankton; Bacteria. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00224/33557/31968.pdf |
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| Leblanc, K; Queguiner, B; Raimbault, P; Garcia, N. |
| A one-year survey of the sedimenting particulate material was conducted at the SOFi site located on the edge of the continental slope in the Gulf of Lions (Northwestern Mediterranean) between September 1999 and December 2000. The main focus of this paper was to establish an annual budget of biogenic silica export, to describe the seasonnal pattern of Si fluxes in relation to the organic and mineral C fluxes and to quantify the Si/C decoupling processes during sedimentation. The pattern of the downward flux of BSi was partly typical with increased daily sedimentation rates during spring followed by smaller peaks during summer. However, an unusual sedimentation event was recorded in the bottom trap in February before the spring thermal stratification... |
| Tipo: Text |
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| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00320/43091/42628.pdf |
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| Dauchez, S; Queguiner, B; Treguer, P; Zeyons, C. |
| Nitrogen (N-15) and carbon (C-14) uptake rates and hydrological, chemical and biological parameters were monitored at a single station during spring (March-April 1989) in a coastal eutrophic ecosystem of western Europe : the Bay of Brest. Before the spring growth of phytoplankton populations, total nitrogen and carbon uptake rates were low (almost-equal-to 0.3-mu-mol C.1(-1).h-1 and almost-equal-to 0.025-mu-mol N.l(-1).h-1). During the spring bloom, these uptake rates reached high values (0.5-mu-mol C.1(-1).h-1 and 0.28-mu-mol N.1(-1).h-1); at this time, nitrate was the main source of nitrogen production, although relative preference index (RPI) values showed that ammonium was the preferred nitrogen form for phytoplankton (RPI (NO3) < 1 ; RPI (NH4) >... |
| Tipo: Text |
Palavras-chave: CARBON UPTAKE; EUTROPHIC ECOSYSTEM; NITROGEN UPTAKE; PARTICULATE MATTER; PHYTOPLANKTON. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00102/21282/18891.pdf |
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| Delmas, R; Hafsaoui, M; Le Jehan, S; Queguiner, B; Treguer, P. |
| The fertilization of an eutrophic ecosystem of Western Europe (the Bay of Brest, 180 km super(2)) is observed from 1979 to 1982. Rich inputs in nutrients and dissolved organic matter flow into this semi-enclosed basin which waters are well mixed by the intensive action of tides. Natural and waste waters inputs are variable on a seasonal and annual scale; this induces large variations on the phytoplanktonic communities. This ecosystem presents high levels of primary production and low degree of maturity. By means of a model, the nitrate uptake by phytoplankton photosynthetic activity is simulated during spring 1980. |
| Tipo: Text |
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| Ano: 1983 |
URL: http://archimer.ifremer.fr/doc/00247/35802/34315.pdf |
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| Leblanc, K; Queguiner, B; Garcia, N; Rimmelin, P; Raimbault, P. |
| A study of the biogeochemical cycle of silicon has been conducted in the Gulf of Lion (NW Mediterranean) from September 1999 to September 2000. Most of the year the study site was under the influence of the NW Mediterranean Current, characterized by oligotrophic conditions. A seasonal pattern of silicon stocks was found, showing an inverse annual distribution of biogenic silica and lithogenic silica. Biogenic silica integrated stocks were higher during spring and summer (21.5 and 19.3 mmol m(-2)) due to siliceous phytoplankton Si uptake and build-up of biomass. By contrast lithogenic silica integrated stocks were highest during the fall and winter (61.8 and 45.0 mmol m(-2)), which may be explained by a higher degree of turbulence of the water column,... |
| Tipo: Text |
Palavras-chave: NW Mediterranean; Biogenic silica; Phytoplanktonic community; Limiting nutrient; Seasonal cycle. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00320/43092/42629.pdf |
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