Chlorophyll-a and hydro-chemical dynamics in a backwater system of the Danube, controlled by hydrology
Hein, T.; Schagerl, M.; Heiler, G.; Schiemer, F.
A gradient of hydrological connections between backwaters and the main river was investigated along a lateral transect of a floodplain in the free-flowing section of the Danube downstream of Vienna. Increasing distance from the Danube generally correlated with decreasing influence. Connected backwaters show an increased nutrient concentration via surface-inflows or seepage supply. Nitrate is a key factor indicating river influence. Phytoplankton biomass, measured as chlorophyll-a, shows higher concentrations at mean water than at times of spates. The nutrient pulse by river seepage leads to a biomass increase according to the gradient of connections with the river.