Water quality studies of the Danube river in Belgrade region (Serbia and Montenegro) were performed at five locations, in June and September, 2003. Results of the qualitative, quantitative and saprobiological analyses of plankton and macrozoobenthic communities were used for the water quality assessment and the categorization of the watercourse examined. The bioindicator analysis points to the presence of mild organic pollution, water quality varying between the 2nd and 3rd class.

The paper presents the results of the water quality studies of the Sava river in Belgrade region (Serbia and Montenegro). The investigations were performed in June and September, 2003. The sampling area covered five locations along the 61.5 km of the river course. Studies included the qualitative, quantitative and saprobiological investigations of plankton and macrozoobenthic communities. The bioindicator analysis points to the presence of mild organic pollution indicating thus 2nd and 3rd-2nd class of water quality.

Studies of the plankton copepods also included the area of continental shelf and the Southern Adriatic deep valley with pronounced ocean characteristics. The deep waters of Southern Adriatic are inhabited by numerous species of all depth zones, with a pronounced domination of ocean forms, similar to the Mediterranean. The quantity of copepods in the area of open surface waters shows a pronounced spring maximum of abundance. The abundance of overall copepod population decreases from the shore toward the open sea of Southern Adriatic valley, with an increase of species abundance in plankton. That area is governed by stenothermal and stenohaline conditions. The Copepoda community is characterized by stenothermic and stenohaline species. Ranges of many of these are not increased horizontally toward the northern parts of Adriatic, and the individuals carried north by water currents quickly die.