Study of the Effect of Certain Physicochemical Parameters on the Distribution of Toxic Planktonic Taxa in Two Oceanic Sites Mehdia and Moulay Bousselham, Rabat Sale Kenitra Region, Morocco

The diversity of phytoplankton communities in marine waters depends on the environmental, physical, chemical and biological factors in which they occur. The aim of our work is to determine the effect of certain physicochemical parameters on the proliferation of five planktonic taxa (1: Alexandrium 2: Dinophysis 3: Gymnodinum; 4: Pseudonitzschia; 5: Proocentrum) identified on the sites of Mehdia and Moulay Bousselham, Gharb of Moroccobetween 2017 and 2018. The results confirm the presence of these toxic taxa in both sites but with different densities. The ACP has allowed separating two distinct groups with coefficients of determination of more than 70%. Indeed, the first group concerning the site of Mehdia, it is characterized by an abundance of the taxa of Gymnodium and Pseudoni, which prefers salt water and oxygenated, thus important phosphate and nitrate levels. Moreover, unlike the temperature factor. However, the second group concerning the Moulay Bousselham site is located on the positive side of the axis, essentially characterized by moderately high temperatures. These conditions are favorable for the Dinophysis, Alexandrum and Proocentrum taxa. This trend makes it possible to classify the Moulay Bousselham site as a risk zone. In light of these results, the authorities of all stakeholders in the sector must increase efforts to overcome this constraint.