author(s)
Sarbjeet Kaur and Prabjeet Singh

abstract
The present study on river Sutlej deals with the seasonal variations in the diversity of phytoplankton and zooplankton population at two different sites of the river (one is River Sutlej before the confluence of the Buddha nallah (S-1) and second is River Sutlej after the confluence of the Buddha nallah (S-2)). Studies revealed that phytoplankton population was dominated by members of Bacillariophyceae, Chlorophycea, Cyanophycea and Euglenophycea and Zooplanktons population was dominated by Protozoan, Rotifer and Crustacea. Relative abundance of Bacillariophycea and Euglenophycea was higher at S-2 as compared to S-1 whereas that of Chlorophycea and Cyanophycea was higher at S-1 as compared to S-2. Relative abundance of Crustacea and Protozoa was higher at S-2 as compared to S-1 whereas that of Rotifera was higher at S-1 as compared to S-2 during the monsoon period.