Assessment of planktonic diversity in river Chenab as affected by sewage of Multan city

A study was carried out to investigate the monthly variations in planktonic life of river chenab as affected by sewage of multan city by analyzing frequency of occurrence,relative abundance and diversity index of plankton life. density and diversity of plankton was used as a measure of water quality. phytoplankton were abundant as compared to zooplankton. of the 86 phytoplankton genera recorded,13 were of cyanophyta,34 of chlorophyta,28 of chrysophyta,3 of cryptophyta,5 of euglenophyta and 3 genera of pyrrhophyta. eighteen genera of zooplankton were observed including 12 of protozoan,5 of rotifers and one genus of cladoceran. total number of organisms was 1835,out of which 1733 were phytoplankton and 102 were zooplankton. diversity index of phytoplankton ranged from 3.34 to 6.79 and diversity index of zooplankton ranged from 0.51 to 2.58. it may be concluded that the quality of chenab water is marginally fit as the diversity index of zooplankton was less than three throughout the study period.