Water quality and zooplankton community of the Eme River, Umuahia, Southeast Nigeria

Abstract. Aquatic ecosystems and biota are often adversely affected by anthropogenic activities. Consequently, zooplanktons have been used to monitor anthropogenic impacts because of their sensitivity to their environment. Water quality and zooplankton community of the Eme River, Umuahia, was assessed between December 2017 and November 2018. The study was carried out in six stations in relation to human activities. Human activities in the watershed were dominated by sand mining. A quantitative filtration method was used for the zooplankton sample collection while standard sample collection and analytical methods were used for the water samples. The zooplankton species recorded were 27 while the most abundant zooplankton group was Rotifera. A known pollution indicator, Daphnia pulex, had the highest number of individuals. The effects of human activities in the watershed were reflected in the results of some of the physicochemical parameters of the river. The zooplankton assemblage and community structure also reflected the effects of human activities in the river. Combined effects of human activities and season contributed to the relatively low zooplankton abundance recorded particularly in some downstream stations. The impacts of sand mining on water quality and zooplankton were more remarkable in the downstream stations (4 6) where the activity was intense while a large number of children swimming and related activities during the dry season had some impacts in station 1. The dominance of indicator and tolerant species indicated that the river was undergoing eutrophication. Sand mining among other observed anthropogenic activities was a major contributor to the nutrient enrichment in the river. The major water quality parameters influencing the zooplankton community structure was revealed by canonical correspondence analysis.