Physicochemical characteristics and phytoplankton abundance of nkisi river, anambra state

An assessment of Physico-chemical parameters and phytoplankton diversity in Nkisi River in Anambra State was conducted for a period of eight months from February 2021-September 2021. Water samples were collected from three sampling stations of the river every month in sterilized containers during the course of the study. The study stations are Trans Nkisi (S4), Omaga Phase II (S5), and Ozalla Layout (S6). The samples were analysed for both physicochemical attributes and phytoplankton diversity. Phytoplankton species were determined following standard procedures. A total of twenty three species of phytoplankton were encountered in Nkisi River. Chlorophyceae was the dominant group of phytoplanktons in the river, accounting for 38.3% in Nkisi River. The most abundant phytoplankton species in Nkisi River was Navicula spp accounting for 6.67 %. A total of 127, 144 and 119 phytoplanktons were recorded for Station 1 (S1), Station 2 (S2) and Station 3 (S3) respectively in Nkisi River. 20 phytoplankton species cut across the 3 stations in Nkisi River while none was entirely unique to the 3 stations. Nkisi River recorded high diversity indices value for Chlorophyceae = 2.24 and least value for Cyanophyceae = 1.557. The physico-chemical attributes of the river were investigated by measuring the degree of correlation with the phytoplankton diversity. The phytoplankton diversity of the river correlated positively with physico-chemical parameters. The result revealed a deterioration of water quality of the river due to industrial, commercial and anthropogenic activities. The status of phytoplankton diversity of Nkisi River was low indicating that the river is polluted and that the water chemistry has direct effect on plankton diversity. Cyanophyceae have shown less number of phytoplankton abundance in most of the sites in the river. The discharge of industrial effluents, domestic wastes and other anthropogenic activities has altered the structure of phytoplankton community of the river. There is need for legislation and conservation strategies to restore the water quality and protect the river from further degradation.