Studies on the Composition and Abundance of phytoplankton assemblages in the Adiabo River were carried out for six (6) months. Twenty litres (20L) of Adiabo River water samples were collected in each month throughout the study period at high tide. Phytoplankton sample were collected by filtration using bolting preserved in formalin. Phytoplankton analysis was carried out using numerical counts with compound microscope and identification. A total of Forty two (42) species of phytoplankton belonging to six (6) families were identified. Chlorophyceae (Green algae) and Bacillariophyceae (Diatom) were the most abundant phytoplankton family, followed by Cyanophyceae (Blue-green algae), Cryptophyceae and Euglenophyceae (Green flagellates), of the total phytoplankton abundance respectively. Chlorophyceae and Bacillariophyceae showed progressive and abundance across all months while Cyanophyceae, Cryptophyceae and Euglenophyceae however, showed no spatial bias. Chlorophyceae was also the most dominant family, while Bacillariophyceae was observed to be subdominant groups. Similarity of species occurrence was generally observed across all months. This study indicates high productivity of phytoplankton, also the presence of certain Cyanophyceae taxa indicates environmental degradation in Adiabo River.
