A great floristic variety has been noted according to qualitative analysis of phytoplankton. The presence of 187 taxa from 7 divisions of algae has been noted. The results of quantitative analysis show the dominance of centric diatoms. The high values of biomass that point out on the trophicity increase are noted on the strech from Nestin to Zemun (Serbia) with the maximum at Centa (Serbia) with 15,885 mg/cubic dm. Downstream Zemun, it has been noted gradual decrease of biomass up to Pancevo (Serbia), and afterwards downstream the considerable reduction all the way up to Brnjica (Serbia), where the value of algal biomass was 1,697 mg/cubic dm.

This paper presents the results of the examinations of phytoplankton community of the Tamis river from March 2003 till December 2004. During the investigation it was determined 136 algal taxa from 6 divisions: Cyanophyta (10 taxa), Chrysophyta (1 taxa), Bacillariophyta (66 taxa), Pyrhophyta (4 taxa), Euglenophyta (14 taxa) and Chlorophyta (41 taxa). The contents and the structure analysis of phytoplankton as well as saprobiological valorization of water quality, has been carried out in the Republic Hydrometeorological Service of Serbia. Results of quality and quantitative analysis point to domination of Bacillariophyta and Chlorophyta. The index of saprobity given on the basis of Pantle-Buck method indicated that the quality of water of Tamis river on Jasa Tomic border locality belonged to beta and beta-alfa mesosaprobic category.

In this paper the results of the application of WQI method on Vojvodina main rivers and canals are shown. There were investigated 41 localities, from April 2002 to May 2003. There was observed high degree of correlation between the WQI values and the qualitative composition of the desmid community. Exceptions to that rule were noticed, since that WQI is not sufficient parameter of the water quality.

Recent surveys of river Tisza (Serbia) have shown that class Oligochaeta is commonly present as dominant member of benthic macroinvertebrate community. Knowing the fact that this class is very good indicator of organic upload in aquatic ecosystem, in this paper it is used for saprobiological water quality assessment of middle and lower stream of river Tisza in summer of 2002, 2004 and 2005. Results presented as saprobiological indices, showed that water quality of river Tisza (Serbia) was alfa-mesosaprobioc (the third class) during research period.