engleski

Dynamics of phytoplankton and periphytic algae in a Danubian floodplain lake : a comparative study under altered hydrological conditions

The changes in composition and abundance of phytoplankton and periphytic algae during the successions of dry and flood phases were investigated in a eutrophic, Danubian floodplain lake during the summer-autumn period. The in-lake conditions (high nutrient concentration, high water temperature) during the dry phase in summer, stimulated an increase of phytoplankton abundance and supported cyanobacterial bloom development. An extremely high flood pulse altered the physical and chemical environment of the lake. Consequently, phytoplankton abundance was low with dominance of species characteristic for a mixed environment. Contrary to phytoplankton, abundance of periphytic algae reached the peak value in the conditions of flooding with the predominance of diatoms with low to medium resistance to physical disturbance. Periphytic algal abundance was reduced during the dry phase in the conditions of high grazing pressure. The rapid increase in abundance of prostrate diatoms indicated the periphyton recovery. Altogether, flooding dynamic appeared as the most influential cause of dominance and abundance changes of phytoplankton. In the same time, periphytic algae were found to benefit from the environmental changes caused by flooding. Further investigations are necessary to elucidate a variety of factors important in controlling periphytic algal development in complex and dynamic ecosystems like temperate floodplains.

flooding; floodplain; algae; C-R-S concept

nije evidentirano