StatusThe thesis was presented on the 16 December, 2005
Approved by NCAA on the 23 February, 2006
Abstract– 0.31 Mb / in romanian
The paper deals with generalizing a long-term research on the zooplankton communities in the major ecosystems of the Dniester River basin – the Middle and Lower Dniester, the Dubasari Reservoir and the Cuciurgan Cooling Reservoir of the Moldovan Power Station.
Data for the past five decades were brought together to analyze the successions of the diversity and quantitative parameters of the zooplankton communities – the taxonomic diversity, dominant species, and abundance, under human impacts. The major factors that brought about the decrease in the diversity and abundance of the community were highlighted. The values of organic matter produced and mineralized by zooplankton were calculated for its major groups.
On the basis of Rotschein’s saprobity index, additional data were drawn regarding to the pollution levels in the ecosystems having been studied. Long-term dynamics of Shannon’s diversity index (ISh) was traced for the zooplankton in different types of ecosystems and the major factors that influence ISh were put forward. Shannon’s diversity index calculated on the basis of zooplankton was analyzed in terms of its usability in indicating the saprobiological state of aquatic ecosystems.
Some hydrochemical factors – content of suspended mineral matter, dissolved organic matter, levels of NH4+ and NO2- ions were researched for their effects on the zooplankton in the Dniester River’s main course.
A complex of trace elements (Mn, Zn, Cu, Co, Mo, and Ni) was tested as a stimulator of the zooplankton in a pond ecosystem. Bioaccumulation coefficients of the aforementioned trace elements were assessed for the water flea Daphnia magna.
An original computer-based application was developed using the modern information technologies. It supports standard operations with databases and allows calculating some aut- and synecological indices.