Taxa Composition, Abundance, Distribution And Diversity Of The Planktonic Organisms Of River Ogunpa, Ibadan, Nigeria
The plankton of a polluted river in Ibadan city, Nigeria was studied during the early rainy season to assess spatial variation in taxa composition, abundance, distribution and diversity. Five sampling stations were established along the course of the river spanning a distance of about 10 kilometers. Forty-eight genera of plankton were recorded; nine of Cyanophyceae, thirteen each of Chlorophyceae and Bacillariophyceae, seven of Protozoa and three each of Rotifera and Crustacea. Members of Cyanophyceae dominated the assemblage accounting for 91.77% of the total plankton abundance. All the major plankton groups except Rotifera and Crustacea were represented at the five stations. Shannon-Wiener diversity index and evenness followed the same pattern for phytoplankton: Bacillariophyceae>Chlorophyceaea>Cyanophyceae. Shannon-Wiener diversity and evenness followed different patterns for zooplankton: Protozoa>Rotifera>Crustacea and Rotifera>Protozoa>Crustacea respectively. High relative abundance of Cyanophyceae and their presence either mostly in the colonial or filamentous form may be indicative of the influence of organic pollution on the plankton community of River Ogunpa.
Keywords: : plankton, composition, abundance, distribution, diversity
IFE Journal of Science Vol. 9 (1) 2007 pp. 17-22