Monitoring the ecological diversity of the aquatic Danube Delta systems in terms of spatial- temporal relationship

The paper proposed the characterization of a comparative biological analysis of aquatic ecosystems of the Danube delta in 7 sampling sites: Mahmudia, Murighiol, Saint George branch, artificial channel, Uzlina downstream, pontoon Uzlina and Uzlina upstream for the samplings period (February 2009 – June 2010). The preliminary results of analysis for the biotic communities determined from all 7 locations demonstrated the following aspects: in the Mahmudia, Murighiol, Saint George branch, artificial channel, Uzlina downstream, pontoon Uzlina and Uzlina upstream control sections from the phytoplanktonic, zooplanktonic and benthic macroinvertebrates components view point, the Danube water system is an eutrophic system equilibrated for class II according to the Norm concerning the reference objectives for the surface water quality classification (Order MMGA No 161/2006); in the Uzlina control section, the phytoplankton is better represented than in the Murighiol control section for numerical density and remanent biomass. Also, dominant species of phytoplankton and zooplankton – for numerical density and remanent biomass – are oligo-betamesosaprobic species; concerning the benthic macroinvertebrates there is a quite high diversity, represented by gastropods and lamelibranhiates species, association of the oligocheta together with chironomidae organisms. The researches will be continued in order to assess the seasonal variations and to estimate the value of the trophic basis, in the 7 control sections of the Danube delta biosphere, because the main actions that must be achieved in this areas in order to accomplish a sustainable management are represented by: the reduction of the nutrient charge in the Danube, especially the Danube delta inputs, controlling the punctiform and diffuse pollution sources and the restoration of wetlands, this being the only way to prove the capacity to support and productivity of the entire Danubian system.