Biogeochemical modelling in the Bay of Seine (France): an improvement by introducing phosphorus in nutrient cycles

Type Article
Date 2000-07
Language English
Author(s) Guillaud Jean-Francois, Andrieux-Loyer Francoise, Menesguen Alain
Affiliation(s) IFREMER, Dept Ecol Cotiere, F-29280 Plouzane, France.
Source Journal of Marine Systems (0924-7963) (Elsevier), 2000-07 , Vol. 25 , N. 3-4 , P. 369-386
DOI 10.1016/S0924-7963(00)00028-2
WOS© Times Cited 42
Keyword(s) Bay of Seine, Phytoplankton, Phosphorus, River plume, Biological two layer box model
Abstract As part of the French National Programme for Coastal Oceanography, this paper focuses on improvement of biogeochemical modelling in the: Bay of Seine (Eastern Channel), by introducing phosphorus in nutrient cycles. The Bay of Seine receives the Seine river, which exhibits very high nutrient concentrations, and this coastal zone constitutes a typical case of eutrophication in a river plume area. In terms of analyses, sequential extraction and analysis of sedimentary phosphorus were used in order, to measure various forms of particulate phosphorus in suspended matter and sediment (calcium-bound phosphate, Fe/Al-bound phosphate, exchangeable phosphate and organic phosphorus). In the modelling approach, the Bay is divided into 42 boxes and a two-layer, vertical thermohaline model is linked with the horizontal circulation scheme to take vertical stratification into account. The previous biological sub-model, with only nitrogen and silicon as nutrients, was improved by taking account of (a) various forms of bioavailable phosphorus (dissolved phosphate, exchangeable phosphate and organic phosphorus) and (b) experimental parameters, which govern the adsorption/desorption of phosphate at the solid-water interface. The ecological model accurately reproduces dissolved nutrient behaviour in the river plume, and concentrations of diatoms, flagellates and zooplankton are consistent with observed values. Simulated exchangeable phosphate and organic phosphorus in suspended matter are in the range of measured concentrations, whereas these particulate variables are simulated with less accuracy in the sediment. After evaluating the respective roles of nitrogen, phosphorus and silicon as limiting factors for phytoplanktonic growth, the model was used to estimate consequences of reduced phosphorus or nitrogen input for phytoplanktonic production in the Bay of Seine.
Full Text
File Pages Size Access
publication-462.pdf 23 402 KB Open access
Top of the page