BIODIVERSITY ASSESSMENT OF ALGAE AS BIO INDICATOR OF WATER QUALITY IN RIVER GALMA ZARIA KADUNA STATE

ABSTRACT Water pollution poses a significant threat to freshwater ecosystems in developing regions. River Galma in Zaria, Kaduna State, Nigeria, is increasingly exposed to pollution from agricultural, domestic, and industrial sources. This study assessed the biodiversity of algae in River Galma as a tool for evaluating water quality. Samples were collected from three locations—upstream, midstream, and downstream—and analyzed for physico-chemical parameters including pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrate, phosphate, and turbidity. Algal species were identified microscopically and quantified to determine their diversity and composition. Results showed that the upstream site, with lower nutrient levels and turbidity, supported diverse algal communities including Navicula, Nitzschia, and Scenedesmus, indicating good water quality. In contrast, downstream sites with higher concentrations of pollutants were dominated by pollution-tolerant species such as Oscillatoria and Microcystis aeruginosa, and showed reduced diversity. There was a clear inverse relationship between water quality and algal diversity. These findings confirm that algae serve as effective bioindicators of water quality, capable of signaling ecological changes in polluted aquatic systems. Algal assessment provides a reliable, low-cost approach to environmental monitoring, especially in regions with limited resources. The study recommends the integration of algal monitoring into routine water quality assessments and calls for stronger pollution control measures to safeguard River Galma.