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| Registros recuperados: 37 | |
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| Dauby, P.; Baeyens, W.F.J.; Biondo, R.; Bouquegneau, J.-M.; Chou, L.; Collette, O.; Dehairs, F.A.; Elskens, M.; Frankignoulle, M.; Loijens, M.; Paucot, H.; Wollast, R.. |
| From 1989 to 1992, five cruises were conducted in an area covering the English Channel, the Celtic Sea and the Gulf of Biscay. During these campaigns, suspended matter was collected by different techniques in order to analyze the spatial and vertical distribution of several particulate trace elements in relation to the global biogeochemical cycle of carbon. It appears that horizontal distribution varies strongly from one element to another and is mainly influenced either by anthropogenic and terrigenous inputs or by scavenging processes. On the other hand, the vertical distribution seems mainly linked to the primary production. In parallel to these trace element measurements, experiments were carried out to estimate the transfer rates of these elements... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2680 |
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| Dehairs, F.A.; Dedeurwaerder, H.; Dejonghe, M.; Decadt, G.; Gillain, G.; Baeyens, W.F.J.; Elskens, I.. |
| During 1980 and 1981 the aerosol burden as well as the wet and dry atmospheric fall-out of Cu, Cd, Pb, Zn, Fe and Mn to the sea have been studied in the Belgian coastal area. Atmospheric Cu, Zn and Cd are observed to be introduced into the sea mainly by wet fall-out, while Fe, Mn and also Pb have a dry and wet fall-out of similar magnitude. Of these elements, Cu, Zn and Cd have the highest washout factors. Furthermore, for all elements, excepted Mn, discrepancies exist between washout factors above land and sea, with values up to 5 times larger above the sea.On the scale of the North Sea, atmospheric fall-out of Cu, Zn, Pb and Cd exceeds by one order of magnitude the combined input of the rivers Scheldt, Rhine and Meuse, while fall-out of Fe and Mn is of... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1982 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10065 |
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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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| Fagel, N.; André, L.; Dehairs, F.A.. |
| We report the results of a geochemical study of sediment and trap material. Major and trace elements (Zr, Ba, rare earth elements, and Th) were analyzed on bulk sedimentary material collected along the NE Atlantic margin. Our aim is to test the widespread use of Ba-barite as a proxy for paleoproductivity in a continental margin area. This environment is of great interest because atmospheric-oceanic exchanges are important. In sediments, the geochemical signatures remain close to an upper crust reference, with flat shale-normalized rare earth elements patterns and constant elementary ratios. The calculated biogenic fraction of Ba or excess Ba (20-45%) remains lower than the excess Ba record in trap material (80-99%). The evolution of the geochemical... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10270 |
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| Dehairs, F.A.; Chesselet, R.; Jedwab, J.. |
| Barite particles are a universal component of suspended matter in the Atlantic and Pacific Oceans. This is demonstrated by scanning electron microscope and electron microprobe analyses of samples collected during the GEOSECS program. These discrete particles, about 1 µm in diameter, account for by far the greatest part of the total particulate barium of most of the filters collected at different depths. Total particulate barium (mean value: 20 ng/kg seawater) was measured on the same filters by instrumental neutron activation analysis.Several observations indicate that biochemical, rather than purely chemical, processes are involved in the formation of the BaSO4 mineral in the water column. Sr/Ba molar ratios among the individual barite grains,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Barite; Barium. |
| Ano: 1980 |
URL: http://www.vliz.be/imisdocs/publications/228699.pdf |
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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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| 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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| Jeandel, C.; Ruiz-Pino, E.; Gjata, E.; Poisson, A.; Brunet, C.; Charriaud, E.; Dehairs, F.A.; Delille, D.; Fiala, M.; Fravalo, C.; Miquel, J.C.; Park, Y.-H.; Pondaven, P.; Quéguiner, B.; Razouls, S.; Shauer, B.; Tréguer, P.. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=10249 |
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| Registros recuperados: 37 | |
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