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| Registros recuperados: 26 | |
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| Baeyens, W.F.J.; Van Eck, B.T.M.; Lambert, C.; Wollast, R.; Goeyens, L.. |
| A general description of the Scheldt estuary, including the hydrology, the sediment transport, the productivity and the biodegradation with respect to their influence on the trace metal behaviour in the Scheldt estuary, is given. The river basin can be divided in several sections according to their morphological, hydrodynamical and sedimentary properties. The zone from km 78 to 55, which corresponds roughly with the salinity zone from 2 to 10 psu, is the zone of high turbidity, high sedimentation and of oxygen depletion, especially in the summer period. That area is called the geochemical filter because the solid/dissolved distribution of the trace metals is controlled by redox, adsorption/desorption, complexation and precipitation/coprecipitation... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: ANE; Netherlands; Westerschelde. |
| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7040 |
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| Baeyens, W.F.J.; Parmentier, K.; Goeyens, L.; Ducastel, G.; De Gieter, M.; Leermakers, M.. |
| Cd, Cu, Zn and Pb concentrations in both dissolved and particulate phase were assessed during 1995. Data Quality Assurance was an integral part of this study and involved all major steps of the analysis procedure such as sampling, sample handling, preconcentration and determination. Desorption and redox processes clearly control the dissolved Cu and Cd profiles. Mobilisation of dissolved Zn is small and essentially restricted to the low salinity area and the late spring survey. Dissolved Pb shows the clearest dilution pattern. The parameters representative of these processes (dissolved oxygen and salinity) also correlate very well with the particulate metal profiles. In addition, the plankton activity (expressed by the chlorophyll-<i>a</i>... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7046 |
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| Mengesha, S.; Dehairs, F.A.; Elskens, M.; Goeyens, L.. |
| The nitrogen nutrition of the phytoplankton community in the neritic and oceanic waters of the western Indian Ocean was investigated during the south-east monsoon (June-July) and intermonsoon periods (November-December). The region is very oligotrophic, characterized by very low nutrient concentrations (surface NO sub(3)<0.5 µM), low phytoplankton biomass (PON similar to 0.85 µmoll super(- 1)) and predominance of regenerated production (maximum f -ratio <0.47). Ammonium was the major nitrogen substrate during the two seasons, supplying 53-99% of the phytoplankton's nitrogen requirement. Nevertheless, both the uptake of nitrate and its relative contribution to total nitrogen removal (f -ratio) were significantly higher during the intermonsoon period... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=1951 |
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| Elskens, M.; Goeyens, L.; Dehairs, F.A.; Rees, A.; Joint, I.; Baeyens, J.. |
| Statistical properties in non-linear regression models of <i>f</i>-ratio versus nitrate relationships were investigated using a case study conducted at the European continental margin (Project OMEX). Although the OMEX data fit within the family of empirical models introduced by Platt and Harrison (1985) Nature 318, 55–58), it is shown that the discrepancy between experimental and fitted values is larger than expected, assuming that the data are accurate. Since the ambient ammonium concentration plays a leading role in regulating new production, the present analysis was extended to include explicitly the effect of ammonium on <i>f</i>-ratio versus nitrate plots. Experimental results based on controlled ammonium additions... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10269 |
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| Baeyens, W.F.J.; Elskens, M.; Gillain, G.; Goeyens, L.. |
| Cu, Zn, Cd and Pb have been analysed in suspended matter and water samples from the Scheldt estuary, collected during five cruises between May 1982 and May 1983. In order to evaluate the overall metal behaviour in the estuary, continuous longitudinal profiles of the total, the particulate and the dissolved metal concentrations are discussed in relation to various specific physico-chemical parameters. By means of correlation and multi-regression techniques, several estuarine processes could be identified which dominate and/or control the behaviour of the individual trace metals in three distinct areas of the Scheldt estuary. The behaviour of the four selected metals was found to show some common features, but is besides this also characterised by many... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7043 |
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| Stroobants, N.; Dehairs, F.A.; Goeyens, L.; Vanderheijden, N.; Van Grieken, R.. |
| The intensity of past biological activity can be correlated with the occurrence of suspended and sedimented barite (BaSO<sub>4</sub>). To date, there is a lack of information on the processes controlling the production of pelagic barite. During the EPOS-2 cruise (November-December 1988), situated in the Scotia Sea-Weddell Sea Confluence, suspended water samples were taken for analysis of total Ba by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and for scanning electron microscopy-electron microprobe (SEM-EMP).The vertical profiles of particulate barium generally show a Ba maximum between 200 and 500 m. SEM-EMP investigation on Scotia-Weddell Sea Confluence profiles provide a possible explanation for the origin of this... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Artemia. |
| Ano: 1992 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2865 |
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| Dehairs, F.A.; Kopczynska, E.; Nielsen, C.; Lancelot, C.; Bakker, D.; Koeve, W.; Goeyens, L.. |
| Observations are presented for stable carbon isotope abundance (δ<sup>13</sup>C) and organic carbon and nitrogen content of suspended organic matter from the Southern Ocean (Circumpolar Current and Polar Front) during spring and early summer. The Polar Front Zone was characterized by elevated plankton biomasses and phytoplankton activity, which also increased significantly over the one-month investigation period. From the beginning of the phytoplankton bloom δ<sup>13</sup>C values of suspended organic matter in the Polar Front were high, exceeding values predicted from the relationship with CO<sub>2(aq)</sub> concentration observed in other areas of the Southern Ocean. Later in the season... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10202 |
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| Semeneh, M.; Dehairs, F.A.; Elskens, M.; Baumann, M.E.M.; Kopczynska, E.E.; Lancelot, C.; Goeyens, L.. |
| Phytoplankton nitrogen uptake is studied in relation to the biomass and structure of phytoplankton community in the Atlantic and Indian sectors of the Southern Ocean. Two scenarios of seasonal evolution of uptake regime and phytoplankton community structure are described. The first scenario includes the Marginal Ice Zone areas of the Weddell Sea and adjacent areas where a predominantly nitrate based, diatom dominated assemblage, thriving in a stable water column at the beginning of the season was transformed into a mainly ammonium based, flagellate dominated assemblage, towards the end of the season. The change in phytoplankton community structure was caused by selective grazing by large grazers and reduced stability of the water column and the shift in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biogeochemical cycle Biomass Community composition Continental shelves Ice edge Nitrogen Pelagic environment Phytoplankton Size distribution Uptake PS; Southern Ocean PSE; Antarctic Ocean. |
| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10255 |
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| Registros recuperados: 26 | |
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