ABSTRACT
Aquatic nitrogen and phosphorus pollution, responsible for eutrophication, has significantly increased due to agricultural, urban, and industrial activities, posing a threat to water quality, including Ikpe River. The growth response of the natural algae, Scenedesmus arcuatus, and Chlorella vulgaris in the river was studied using 0.4 mg/L nitrogen and 0.2 mg/L phosphorus and 3.5 mg/L of Nitrogen and Phosphorus concentrations to analyse the maximum growth of Scenedesmus arcuatus which was obtained in day 8 while the indigenous phytoplankton and that of Chlorella was obtained in day 10 and 12 respectively. The physicochemical parameters were observed, including air temperature, colour, conductivity, dissolved oxygen, phosphate, pH, nitrate, sulphate, total dissolved solid, total alkalinity, total hardness, turbidity, water temperature. The respective results were 30.3 ˚C, 5 PtCoU, 24 µS/cm, 6.0, 0.02mg/L, 6.42, 0.3 mg/L, 7mg/L, 12ppm, 25 mg/L, 15 mg/L, 8 NTU, and 29 ˚C. Periphyton composition consisted of various species such as Mougeotia genuflexa, Eunotia filiformis, Gomphonema pervulum, Navicula sp, Frustulia crassinvervia, Coscinodiscus sp, Navicola notha, Gomphonema lagenula, and Pinularia sp. These results indicate the impact of nutrients on the river, emphasizing the need to regulate input into the river to preserve its ecological balance.
