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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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Naudin, Jj; Cauwet, G; Leveau, M; Lochet, F; Pauc, H; Romano, Jc; Sempere, R. |
Particulate matter from the bottom nepheloid layer, off the Rhone river mouth was sampled with a newly-designed frame code-named SYMPHY. Several spreading phases of the Rhodanian suspensions on the continental shelf were evidenced by currentmeter records, particulate matter analyses, CTD and nephelometric measurements. These data permitted the study of the mechanisms which control the aging of the suspensions during their transfer to a sea with very small amplitude tides. The bottom nepheloid layer can be defined as a vertical concentration gradient resulting from an equilibrium between the horizontal (Rhodanian inputs) and the vertical (surface nepheloid layer) components of the particulate flux. The variability of this equilibrium, controlled by... |
Tipo: Text |
Palavras-chave: BOTTOM NEPHELOID LAYER; PARTICULATE MATTER; CURRENT MEASUREMENTS; HYDROLOGY. |
Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00101/21230/18847.pdf |
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Compiano, Am; Romano, Jc; Delagiraudiere, I; Laborde, P. |
Samples of phytoplankton cultures and of suspended particulate matter from continental, brackish and marine waters were examined by HPLC for the monosaccharide content of their hydrolysable sugar fraction. Eight monosaccharides were currently assayed and their weight compared to HPLC-assayed chlorophyll a concentrations. With the exception of oligotrophic waters, these two variables are well correlated in the various prospected environments. Glucose was always the strongly dominant form, not only in fresh and brackish waters but also in marine samples with high phytoplanktonic biomass. If samples are compared on a salinity basis, only four monosaccharides showed significant differences in their relative concentrations, as a consequence of sampling... |
Tipo: Text |
Palavras-chave: MONOSACCHARIDE; HPLC; PARTICULATE MATTER; SEA WATER; BRACKISH WATER. |
Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21134/18754.pdf |
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Rabitti, S; Bianchi, F; Boldrin, A; Daros, L; Socal, G; Totti, C. |
Some results of a cruise carried out within the Project on the Physical Oceanography of the Eastern Mediterranean (POEM BC-091, October 1991) are reported and discussed. The major aim of this work was to study, in the upper layers of the Ionian basin the distribution of particulate matter, phytoplankton and bacteria, with emphasis on the influence of North Atlantic Water. Some tentative conclusions may be drawn from the results: the examined situation (October) is representative of the final stage of a probably annual cycle of production in an oligotrophic system; the well-developed Deep Chlorophyll Maximum between 75 and 100 m (mainly due to degradation products) does not match the biomass maximum. Possible explanations of this are: a) phytoplankton... |
Tipo: Text |
Palavras-chave: IONIAN SEA; PARTICULATE MATTER; CHLOROPHYLL; PHYTOPLANKTON; BACTERIA. |
Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20892/18506.pdf |
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