Diversity of bloom forming harmful algal species in the central Bonny Estuary, Niger delta, Nigeria

This study was carried out from December 2018 to November 2019 examine the distribution and abundance of harmful algal species (HAS) in central Bonny estuary. Seven sampling stations were established with ArcGIS tool. Microalgae sampled 20 mm mesh plankton net. Nutrients analyzed laboratory using APHA 4500 Method, while physicochemical characteristics determined situ. Results revealed that environmental gradients adequate support life part estuary except for phosphate (2.90 ± 0.22-9.48 1.06 mg l-1). A total 31 HASs categorized into 17 genera three classes determined: Bacillariophyceae (29 species), Chlorophyceae Cyanophyceae (one each). Navicula amphibola had highest density (4.713 103 cells l-1) Pinnularia divergens recorded lowest (0.00049 Total values decreased across seasons 9.157 l-1 dry season 8.907 wet season. Checklist showed five distributed seven stations, two found only Station 2 7. Diversity indices Shannon’s index ranged between 3.17 3.25 evenness 0.78 0.88, Margalef range value (3.09-3.31) considered moderately stable. Therefore, there is a need proper management practices which could help reduce level nutrient discharge