Physicochemical Properties and Microalgal Diversity of Sabon Gari and Rimaye Fish Ponds, Nasarawa State, Nigeria

Abstract

Despite the growing interest in microalgae for their ecological and biotechnological value, there is a lack of detailed studies on the diversity and physicochemical dynamics of microalgae in fish ponds within underexplored regions like Nasarawa State, Nigeria. This study examines the isolation, identification, and physicochemical properties of microalgae in Sabon Gari and Rimaye fish ponds in Nasarawa State, Nigeria, an unexplored area for microalgal resources. Water samples from the ponds were cultured in Blue-green 11 Medium and analyzed for microalgae composition and environmental factors affecting pond health and productivity. Morphological identification revealed the presence of Chlorella sp., Microcystis sp., Scenedesmus sp., and Coelastrum sp. in Sabon Gari Pond, and Euglena sp., Chlamydomonas sp., Scenedesmus sp., Chlorella sp., and Oscillatoria sp. in Rimaye Pond. These species have significant biotechnological applications in biofuel production, renewable energy, water quality management, and pharmaceuticals. The physicochemical analysis revealed significant differences between the ponds in parameters such as pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, turbidity, water hardness, and chloride ions. However, electrical conductivity, total dissolved solids, temperature, nitrate, phosphate, copper, and zinc levels were not significantly different. Nitrate (2.11 mg/L) and phosphate (4.34 mg/L) levels in Sabon Gari Pond were higher, promoting microalgae proliferation, while lower dissolved oxygen (9.19 ± 0.64 mg/L in Sabon Gari and 11.17 ± 0.88 mg/L in Rimaye) indicates early eutrophication, potentially reducing fish yield. Zinc and copper levels were within WHO limits, and no lead was detected. These findings highlight the environmental factors influencing aquaculture productivity in the ponds and emphasize the potential of microalgae for biofuel production, water treatment, and other applications, while also identifying risks posed by eutrophication. It is recommended that regular monitoring and management of nutrient levels be implemented to avert eutrophication. Furthermore, the identified microalgae should be investigated further for their biotechnological applications in renewable energy and water treatment, aiming to boost both environmental sustainability and economic benefits in the region.