Measures of Biodiversity Index of Algal Communities in a Freshwater Ecosystem in Northern Nigeria

Abstract

The study of the diversity, species richness, and abundance of algae was under taken for the period of eight months (February – September 2007) in Shadawanka River, Bauchi State. Assessment of physicochemical characteristics of the river was also attempted to find out the state of the water quality of the river. Four hundred and eighty one species of phytoplankton were recorded. This consisted of 276 species of diatoms, which was made up of 237 species of Pennales and 39 species of Centrales. 123 species of desmids (green algae), 41 species of Euglenophyceae, 34 species of Cyanophyceae, 3 species of Phaeophyceae and Xanthophyceae having 4 species from a single order Heterococcales. Two hundred ad twenty-one algal species in the Epiphytic were identified, 122 species belonged to the Bacillariophyceae. This consisted of 97 species of Pennales and 25 species of Centrales. There were 58 species of Chlorophyceae, 14 species of Cyanophyceae, 7 species of Euglenophyceae, and 3 species of Xanthophyceae respectively. Seventy one species of Epilithic were observed, which included 33 species of Bacillariophyceae consisted of 22 species of Pennales and 11 species of Centrales, 23 species of Chlorophyceae and 9 species of Cyanophyceae and 6 species of Euglenophyceae. The highest species richness (16.50) was obtained in the phytoplankton and the lowest (3.82) was in the Epilithic whilst Epiphytic was an average (10.51). The similarities between phytoplankton and Epiphytic and that between Epiphytic and Epilithic were same (0.17), whilst the similarities obtained between the phytoplankton and Epilithic communities was lower (0.14). The River is well oxygenated (DO>9.8mg/L) and is Characterised by moderate nutrient levels, high electrical conductivity (>204 µmScm^-1) and low BOD (2.1-6.4mg/L). pH was circumneutral, having three regimes, this attest that the water is not polluted and can support other forms of aquatic life

Keywords: Centrales, Pennales, Physicochemical, Phytoplankton, Epilithic, Epiphytic