Phytoplankton composition and distribution in the bandama river (Côte d’Ivoire) in relation to physico-chemical parameters

The Bandama river basin offers a highly diversified range of environments: lacustrine environments and lotic environments respectively upstream of Lake Kossou, downstream of Lake Taabo and between the two lakes. It is exposed to various types of anthropogenic pressure that can disrupt its ecological functioning. Conservation of its biodiversity in order to ensure effective and sustainable management of its resources requires a better understanding of one of the primary biological compartments of the food web, which is made up of micro-algae. The aim of this study is to determine the population and distribution of phytoplankton in the waters of the Bandama River. The physico-chemical parameters (pH, Temperature, Conductivity and Dissolved Oxygen) were measured in situ using a portable multiparameter HANNA model HI9828. Samples were taken using a plankton net with a mesh size of 20 µm. The various sampling campaigns took place each season throughout 2013. Out of a total of 170 phytoplankton taxa, the Chlorophyta phylum had the highest number of taxa with 75 species, or 44.11%. Next come the Euglenophyta (44 taxa or 25.88 %), the Heterokontophyta (36 taxa or 21.17 %), the Cyanoprokaryota (12 taxa or 7.05 %) and finally the Dinophyta (3 taxa or 1.76 %). The results of the Redundancy Analysis showed that Chlorophyta and Cyanoprokaryota have a preference for nutrient-rich environments. pH and temperature had a much greater influence on the distribution of Chlorophyta. This study assesses the influence of physico-chemical parameters on the population and distribution of phytoplankton in the waters of the Bandama river basin.