Toward a Mediterranean coupled model of the nitrogen cycle

The general circulation horizontal and vertical processes interact with the biogeochemical cycles at proper scales in this study the lower trophic level variability induced by physical forcings in the Mediterranean is investigated by means of a 3D coupled hydrodynamical ecological model. The trophic dynamics are described using an aggregated model based on inorganic nitrogen, phytoplankton and detritus. The seasonal cycle shows marked spatial differences according to the prevailing cyclonic and anticyclonic regime, creating zonal and meridional permanent trophic gradients. The open ocean ecosystem response is moreover influenced by coastal boundaries/open ocean exchanges and by Ekman suction enrichment. This leads to the tentative conclusion that the upper thermocline circulation determines directly or indirectly the distribution of the dissolved inorganic nitrogen concentration. This is supported by the comparison with CZCS images.