Since we could not calibrate the biological model parameters from observed data and the simulation was so short, it is very probable that the results of the biological model integration will be almost completely driven by the initial conditions. In so short a time, the dynamics of the model should still be hidden by the initial conditions' influence.
We will probably observe high primary production where the nutrients were abundant at the start of the integration, i.e. in the Gulf of Cadiz.
Moreover, in order to verify Van Geen's hypothesis of a shelf metal trap in the Gulf, the primary production should be high in the area for the whole year. Our short-term simulation will not enable us to validate or invalidate this hypothesis since it was only 21 days long.
Figure 5.12 shows the spatial distribution of the phytoplankton on the area covered by the coarse model and on the nested model. We can see that the production is relatively high in the Gulf of Cadiz, where we put high concentrations of nitrate at the start, and along the Costa Del Sol, which is the name of the Spanish coast on the Eastern side of the Straits.
This second production area exists mainly thanks to a rather strong and constant upwelling linked to the Western Alboran Gyre. The upwelling drives nutrients from the deep Mediterranean Sea up along the continental slope to the shelf and so enables primary production there.
The comparison between the nested model's results and the coarse model simulation shows that the spatial structure of phytoplankton is far more precise in the nested modeil, where the grid is refined. We can see the advantages of refining the grid for this kind of studies and so the remaining figures will be drawn only in the nested area.
The spatial repartition of ammonium, nitrate, zooplankton and organic matter is drawn at figures 5.13 to 5.16 for the nested area. We can see that production occurs on the Spanish shelf and that the organisms are driven towards the Straits of Gibraltar with the surface water in this area. This can so confirm that Van Geen's hypothesis could be valid for entrainment of organic-complexed metals to the Mediterranean.
Every following profiles are drawn at the depth of , since the water column is well mixed at the beginning of January and the profiles are almost homogeneous along the vertical.
Figure 5.12: Phytoplankton concentrations in the coarse model and the nested model
Figure 5.13: Nitrate concentrations in the nested model
Figure 5.14: Ammonium concentrations in the nested model
Figure 5.15: Zooplankton concentrations in the nested model
Figure 5.16: Organic matter concentrations in the nested model