Caravan Y. The hydrochemical regime and ecological state the Upper Siret river.

The thesis is devoted to investigation of hydrochemical regime and ecological state of the Upper Siret river and its tributaries. Hydrochemical regime of Siret river was established on the basis of data provided by hydro-meteorological service on the period 1961-2006. The own research in the period 2007-2011 was based on the data of hydrochemical regim and contained the determination of concentration of toxic elements and organic toxicants in water of Siret river and its tributaries. The next bloc of the research was the estimation of hydromorphological parameters of the bed and floodplain of the Siret and its tributaries. On the basis on these results the coefficients of anthropogenic interference on the water body were calculated. The third part of the own research included the determination of the species composition, saprobity, species diversity, abundance, biomass of phytobenthos and phytoperyphiton communities of Siret river and its tributaries. The formation of aquatic ecosystems is caused as a result of processes occurring in the catchment basin and throughout the river. We cannot fully assess the condition of aquatic ecosystem by means of chemical analysis of water quality. That is why the biological parameters are very important to know. Based on these parameters a comprehensive assessment of the ecological condition of the Siret river and its tributaries has been done.