Planktonic Biodiversity and Physico-Chemical Parameters of Awba Reservoir, University of Ibadan, Ibadan, Nigeria

Abstract

Knowledge of the physical, chemical and biological conditions of a water body is not only useful in assessing its productivity but would also permit a better understanding of the population of organisms within the water. Awba reservoir is a major source of water for the University of Ibadan. This study determines the physcio-chemical parameters as well as the biodiversity of the planktons in relation to these parameters. Water samples were collected twice in a week for physico-chemical parameters determination and estimation of planktons in the water. Temperature, pH, Conductivity, Transparency, and Dissolved oxygen were the physcio chemical parameters assessed. The different organisms in the sub-sample were identified using plankton guides. Mean temperature, conductivity, transparency and dissolved oxygen values in the four sites were significantly different (P< 0.05). The mean pH value ranged from 7.94 in Site A to 8.109 in site B, there was no significant difference in pH values of the four sites. A total of 31 plankton genera belonging to 7 plankton groups were encountered in the reservoir, cyanophycae group are the prominent phytoplanktons, with microcystis ranking highest. Crustaceans make up the largest part of zooplankton group followed by rotifers. Among the crustaceans group, daphnia is the most prominent. The least plankton group, rotifers was represented most by notholca. The range of ammonia concentration at the time of study was between 1.22mg/l and 4.62mg/l. this is a little higher than the concentration specified by the United State Environmental Protection Agency which is 0.02mg/l which indicates that the reservoir is under pollution stress.