QUANTITATIVE AND QUALITATIVE EVALUATION OF PHYTOPLANKTON IN THE SITE ROSCI0066 DANUBE DELTA - THE MARIN AREA - A CASE STUDY IN SEPTEMBER 2012

The phytoplankton is a fundamental link in the trophic chain and is one of the indicators to assess the status aquatic ecosystem. To assess the qualitative and quantitative structure of Phytoplankton in September 2012 has been used samples collected from marine area of Danube Delta Biosphere Reserve with plastic water sampler (Niskin type). The qualitative structure of phytoplankton was characterized by the presence of 53 species belonging to six algal taxonomic groups (Bacillariophyta, Dinoflagellata, Chlorophyta, Cyanobacteria, Chrysophyta and Euglenophyta). The diatoms have dominated the number of qualitative structure of phytoplankton species in most areas, their share ranging between 39% and 54%. The dinoflagellates were the second group that diversity, the proportion ranging from 27% and 44%. September 2012 was characterized by values of densities between 67 - 453?103 cel?l -1 and for biomasses between 0.22 ? 1.08 g?m-3 . The diatoms have dominated for more than 70% in density and 50% in biomass. The conclusion of this case study, confirmed by previous researches, is that the phytoplankton is not presented as an integral whole viable, but is rather the appearance of a heterogeneous floating tanatocenosis. The site ROSCI0066 Danube Delta - the Marin Area does not have a specific phytoplankton, because the mixed waters from here are always pushed by winds and currents in all directions, especially towards South.