Environmental features formation of algoflora middle flow zarafshan river (Uzbekistan)

Abstract

Algoflora of the Zarafshan River was formed by the integrated influence of environmental factors. The river is divided into 3 parts and this part is distinguished by a number of environmental factors such as the chemical composition of water, water temperature, transparency, flow rate, pH, etc. 331 species were identified in the river algoflora and within the species taxon. The groups of algae are analyzed by the ratio of water temperature, by mineralization of water, by the habitat of algae, and indicator-saprobic species. Water temperatures are crucial for the distribution and development of algae. In the spring, 169 algal flora were identified, in the summer of 210, in the autumn of 13 and in the winter of 88 of algae. In the river algoflora, 16 eurythermal and 315 stenothermal algae species were established. Mineralization of river water varies from beta-oligagaline to alpha-oligogaline. The river waters are mainly freshwater and in some places less often fresh-brackish. This ensures the distribution of fresh-salt-water algae in the middle and lower parts of the river. The river algocenoses are distributed as follows: phytoplankton 62, phytobenthos 134, phytoplankton-phytobenthos 66, periphyton 62 and epiphyte 7 int. From the river algoflora, 97 species and varieties of saprobic-indicator algae were identified. Using these species, the ecological and sanitary state of the river was determined. Indicator-saprobic algae is not evenly distributed over the seasons of the year. Keywords. Environmental factors, taxa, eurytherm, stenotherm, freshwater, freshwater-salt-water, salt-water species, indicator-saprobic species, algocenoses. DOI: 10.7176/JSTR/6-07-09