The Study of Phytoplankton and Limnological Variables as Water Quality Indicators of River Rima, Sokoto, Nigeria

Abstract

Water quality is neither a static condition of a system nor can it be defined by the measurement of only one parameter rather, it is variable in both time and space hence it requires routine monitoring to detect the fertile pattern and changes over time. Water quality in the present study was measured using various methods. The biological analysis (i.e., phytoplankton communities) was carried out with the support of the interpretation of the results obtained from the physicochemical analysis of the water. The climatic factors such as the temperature fluctuated from 18.500c to 23.500c to 20.500c then 23.500c respectively from January to April. Phytoplankton composition, Chlorophyceae was the highest with 8 species and 6870mg/l in total, followed by Bacillariophyceae with 4 species and 2310mg/l in number then Cyanophyceae with 3 species and 1920mg/l in number. In general, the overall average phytoplankton abundance in the study area was 11,100cells/l. On the other hand, the phytoplankton abundance was low in the first two months as a consequence of relatively low temperatures, even though nutrient levels, especially nitrate levels were high during this period. Phytoplankton reflects water quality through changes in its community structure, patterns of distribution and the proportion of sensitive species. Water quality was evaluated using water quality index, which was 55.05 for January, 46.43 for February, 54.58 for March, and 48.16 for April. The average for limnological variables was taken and used to evaluate the water quality, and the result was 50.45. There were no high nutrient concentrations measured during the study period nor was there any dominance of harmful phytoplankton species