Algoflora of the Zarafshan River middle stream and its relationship with indicator-saprobic species

The author studies taxonomic, floristic, comparative, ecological and indicator-saprobiс features of algoflora of the Zarafshan River middle stream. The study was conducted at 10 observation points located along the river. These points are selected by location of such polluting sources as river channels, large reservoirs, sewage domestic, industrial areas and major cities. It is revealed that in the river there are 331 species and varieties of algae. They belong to 81 genus, 38 families, 16 orders, 11 classes and 5 departments. 97 species and varieties of these are an indicator-saprobic algae. The first three points of the environmental conditions are almost the same. In these areas 119 species and varieties are defined, 37 species of them are indicator-saprobic species. The middle saprobic index is 1.27; alpha-oligosaprob, class 2, category – 2b; the water is cleaner in 4–7 observation points of the river. Here 200 species are identified, 56 species of them are considered to be indicator-saprobic species. The middle saprobic index is 1.61; .beta.1-mezosaprob, class 3, category – 3a, the water is clean enough. In 8–10 observation posts only 125 species were found, 44 species of them are indicator-saprobic species. Middle saprobic index reached 1.84; beta.1-mezosaprob, class 3, category – 3a, the water is clean enough. Down the river stream the saprobic index, saprobic Educastional level of algae and water pollution gradually increases.