Identification of Planktonic Genera/Species and Determination of the Physicochemical Factors Favoring the Growth of These Species in Cape 7 (Aftissat) Zone, South of Morocco

Abstract

The diversity of oceanic phytoplankton communities depends in part on environmental, physical, chemical and biological factors where they are. The study that we conducted in cape 7 (Aftissat) zone, south of Morocco, located 232 km south of Laayoune city and 62 km south of Boujdour city, aims at the identification of planktonic genera/species and determination of the physicochemical factors favoring the growth of these species. The study was carried out on 427 samples, distributed, therefore, as follows, 57.2% (n = 245) of the samples during the year 2016 and 42.5% (n = 182) in the year 2017. In addition, 32.8% and 27.6% of the samples were taken, respectively, in winter and autumn, 24.4% of the samples in summer and 15.2% of all samples taken in the spring. We have identified 30 phytoplankton species, of which 70% (n = 21) are diatoms, 26.67% are dinoflagellates and one species is silicoflagellates . Moreover, the most abundant species in the diatoms are Navicula sp. (69), Licmophora (47), Nitzschia sp. (35), Pseudo nitzschia spp. (31) and in the class Dinoflagellates , Scrippsiella spp. (24), Protoperidinium spp. (11). The physicochemical parameters show very significant associations with density, so they favor a very high abundance species, especially those belonging to the diatom class. Some toxic species have also been identified, but with very low frequencies, below the norm. The cape d’Afissat has a very important role in the economic life of the region, so we must increase efforts to preserve it and if it is possible to improve the quality of water.