Assessment of Physiochemical Characteristics and Phytoplankton Diversity of Chanchaga-Gbarako River Minna, Niger State

ABSTRACT Aquatic ecosystems are vital for environmental sustainability, yet they are increasingly vulnerable to anthropogenic pressures and seasonal changes. This study focuses on assessing the physicochemical parameters and phytoplankton community composition in the Chanchaga Barako River, Nigeria, over a four-month period (May to August). The aim was to evaluate the river's water quality and biodiversity by examining key variables such as air and water temperature, dissolved oxygen (DO), biological oxygen demand (BOD), pH, alkalinity, total dissolved solids (TDS), conductivity, nitrates, and phosphates. These parameters exhibited significant seasonal variations, with June recording the highest DO levels (8.60 ± 0.35 mg/L) and August showing the peak BOD (4.60 ± 1.44 mg/L), indicative of fluctuating organic pollution levels. Phytoplankton diversity was led by Chlorophyceae (green algae), which constituted the majority of the population, followed by Bacillariophyceae (diatoms) and Cyanophyceae (blue-green algae). The highest phytoplankton abundance was observed in June, suggesting optimal environmental conditions for algal growth. However, the increasing presence of Cyanophyceae in later months signals potential risks of eutrophication. Biodiversity indices indicated high species richness within Chlorophyceae and Bacillariophyceae, while Euglenophyceae showed limited diversity, underscoring ecological instability. The study highlights that seasonal shifts significantly affect both water quality and phytoplankton dynamics in the Chanchaga Barako River. These findings are critical for informing future water management strategies aimed at preserving aquatic ecosystems in tropical river systems, where seasonal changes can have profound ecological impacts.