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| Lehoerff, Genevieve; Erard-le Denn, Evelyne; Arzul, Genevieve. |
| Four planktonic coastal ecosystems from the western Channel to the southern part of the North Sea have been compared. The characteristics of the south of the North Sea are a very high planktonic biomass with an annual maximum value of 45 mg C m-3 h-1 for primary production, a maximum of 11 mg m-3 for Chlorophyll a and 60 mg C m-3 for zooplanktonic biomass (expressed in term of carbon weight), linked with an oscillating ecosystem. In the western Channel primary production shows an annual maximum value of 8 mg C m-3 h-1, die chlorophyll a, a maximum of 2.5 mg m-3 and zooplanktonic carbon weight of 14 mg C m-3 linked to a greater inertia in the system. Turnover is faster in the north. Trophic efficiency ratios have been calculated and linked to hydrodynamic... |
| Tipo: Text |
Palavras-chave: CHANNEL; COASTAL WATER ECOSYSTEM; PLANKTONIC BIOMASS; TROPHIC EFFICIENCY; IMPACT. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21130/18750.pdf |
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| Hoch, Thierry; Menesguen, Alain; Bentley, D. |
| A simple model of the nitrogen cycle in the Channel is proposed. Based on the long-term circulation, this box-model permits the description of the spring phytoplankton bloom in the whole Channel. Spring western thermal stratification has not been taken into account; consequently, the earliest phytoplanktonic development is observed in the eastern Channel, followed by the western, deeper part. This model also shows the influence of nutrient supply from the rivers on the Channel ecosystem, and particularly the influence of the river Seine on the chlorophyll concentrations along the eastern French coast. Comparison of calculated data with measurements shows a fairly good agreement in the eastern Channel but discrepancies are encountered for the western part.... |
| Tipo: Text |
Palavras-chave: CHANNEL; BOX-MODEL; NITROGEN; PHYTOPLANKTON. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21128/18748.pdf |
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| Laane, Rwpm; Groeneveld, G; Devries, A; Vanbennekom, J; Sydow, S. |
| Recent measurements (1986-1988) of the distribution of the concentration of different nutrients (nitrogen, phosphorus and silicate) in the Dover Strait have been used, combined with older results, to calculate the total flux (dissolved and particulate) of nutrients into the North Sea. Special efforts are made to take into account in the fluxes the tidal, geographical and temporal variations in the concentrations of the different nutrients. No vertical gradients in the concentration of the different nutrients were found. Increased nutrient concentration was found in the coastal zones of England and France, compared to the Atlantic water in the central part of the Dover Strait The variation within a single year and between different years in the data... |
| Tipo: Text |
Palavras-chave: NUTRIENTS; FLUXES; NORTH SEA; CHANNEL; TRENDS. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21125/18745.pdf |
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