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| Dupont, Jp; Collins, Mb; Lafite, R; Nash, L; Huault, Mf; Shimwell, Sj; Chaddock, S; Brunet, C; Wartel, M; Lamboy, M. |
| During a survey at six stations in the Dover Strait, from July 1990 to November 1991, water samples were collected to measure : suspended sediment load and its organic content; particle characteristics; photosynthesis pigments; and heavy metals. In this contribution, particle measurements are interpreted in terms of hydrodynamical effects and seasonal evolution. Multi-modal grain size spectra are indicative of depth and cross-sectional variations, from die coastline to the central waters. Tidal variations, biological productivity and wind effects can be identified. Suspended particulate matter (SPM) components (determined using SEM, when combined with size spectra) illustrate hydrodynamical, geomorphological and biological effects on the composition of the... |
| Tipo: Text |
Palavras-chave: SUSPENDED MATTER; DIATOMS; DOVER STRAIT; ENGLISH CHANNEL. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21073/18698.pdf |
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| Bergeron, Jean-pierre. |
| In temperate neritic areas, meteorological conditions prevailing during winter and the following spring play a major role on the main features of the spring development pattern of pelagic ecosystems. Interannual fluctuations of this environment lead to qualitative and quantitative variations of secondary production which may strongly influence processes regulating the recruitment of many species. A method for assessing pelagic secondary production is based on measurement of the activity of an enzyme, aspartate transcarbamylase, and has been carried out during spring periods for six years in succession, in the southwestern part of the English Channel. These works have permitted the establishment of a close correlation between the quantitative variations of... |
| Tipo: Text |
Palavras-chave: ASPARTATE TRANSCARBAMYLASE; ENGLISH CHANNEL; RECRUITMENT; DOVER SOLE; ZOOPLANKTON. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00072/18303/15883.pdf |
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| Chou, L; Wollast, R. |
| The distribution of dissolved Al in the Channel along the English coast shows the existence of a strong gradient of this element extending over a distance of several hundred nautical miles. These profiles suggest that wind-driven export from the North Sea to the Channel is seasonally important. These findings confirm the predictions of the recent circulation models of Salomon and Breton (1991). A gross mass balance of dissolved Al in the Channel indicates that the input of the river Seine is insignificant and that the contribution of other minor fresh water sources cannot account for the observed values. The input of dissolved Al from the North Sea seems thus to be the most likely largest source of this element in the Channel. This could also be the case... |
| Tipo: Text |
Palavras-chave: ENGLISH CHANNEL; NORTH SEA; DISSOLVED AL; DISPERSION; SEINE. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21078/18703.pdf |
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| Lhelguen, S; Madec, C; Lecorre, P. |
| Uptake of nitrogenous nutrients (NO3-, NO2-, NH4+ and urea) by phytoplankton was measured over an annual cycle at a coastal station in the well-mixed waters of the western English Channel. Seasonal changes of nitrogen uptake showed a single, but spread-out, maximum in summer. The phytoplankton took up the various forms of nitrogen simultaneously. Ammonium uptake accounted for 48% of the total nitrogen uptake and was quantitatively important from the beginning of spring until early autumn. Nitrate uptake was relatively less important (32% of total nitrogen uptake) though nitrate was the major component of available inorganic nitrogen. Nitrate uptake rates were comparable to those of ammonium in winter and spring, but were much lower than the latter in... |
| Tipo: Text |
Palavras-chave: NITROGEN; UPTAKE; PHYTOPLANKTON; ENGLISH CHANNEL; SEASONAL CYCLE. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21129/18749.pdf |
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| Brylinski, Jm; Aelbrecht, D. |
| Zooplankton and current studies were carried out in the coastal front of the Dover Strait. We show that the maintenance of both offshore and inshore planktonic communities is due to two coupled phenomena: 1) the residual drift of water differs in the upper and in the deeper waters; and 2) the vertical distribution of plankton differs for inshore and offshore species. In the frontal area, the coastal species remain in the lower water layer where the residual drift is landward. Conversely, the offshore species remain in the upper water layer where the residual drift is seaward. |
| Tipo: Text |
Palavras-chave: ZOOPLANKTON; FRONT; VERTICAL MIGRATION; RECRUITMENT; ENGLISH CHANNEL. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21144/18763.pdf |
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| Grochowski, Ntl; Collins, Mb; Boxall, Sr; Salomon, Jc; Breton, M; Lafite, R. |
| Sand transport pathways are predicted, by combining outputs from an hydrodynamic numerical model with empirical sediment transport formulae. Tidal simulations, combined with various wind conditions, are compared with patterns presented in the literature. Results show that tides determine the long-term transport pattern in the area; this consists mainly of an ebb-dominated (North Sea towards Channel) mid-Strait region and flood-dominated pathways along the coastlines, which narrow towards the (Dover) Strait. Localised transport paths are identified; these are believed to be responsible partially for the presence of large sandbanks. Superimposed SW and NE wind activity overwhelms the tidally-induced pattern; this occurs infrequently and long-term pattern is... |
| Tipo: Text |
Palavras-chave: ENGLISH CHANNEL; DOVER STRAIT; SEDIMENT DYNAMICS; MODELING; SANDBANKS. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21075/18700.pdf |
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