MEPS 146:189-205 (1997)  -  doi:10.3354/meps146189

Modelling the biogeochemical cycles of elements limiting primary production in the English Channel. II. Sensitivity analyses

Hoch T, Ménesguen A

This paper presents the general framework of an ecological model of the English Channel. The model is a result of combining a physical sub-model with a biological one. In the physical sub-model, the Channel is divided into 71 boxes and water fluxes between them are calculated automatically. A 2-layer, vertical thermohaline model was then linked with the horizontal circulation scheme. This physical sub-model exhibits thermal stratification in the western Channel during spring and summer and haline stratification in the Bay of Seine due to high flow rates from the river. The biological sub-model takes 2 elements, nitrogen and silicon, into account and divides phytoplankton into diatoms and dinoflagellates. Results from this ecological model emphasize the influence of stratification on chlorophylla concentrations as well as on primary production. Stratified waters appear to be much less productive than well-mixed ones. Nevertheless, when simulated production values are compared with literature data, calculated production is shown to be underestimated. This could be attributed to a lack of refinement of the 2-layer box-model or processes omitted from the biological model, such as production by nanoplankton.

Ecological box-model · Thermohaline stratification · English Channel · Primary production

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