Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The nutrient turnover and the resulting development of phytoplankton biomass were investigated during four river surveys in the free‐flowing reach of the river Elbe under almost constant hydrological and meteorological conditions taking into account the transport time and the time of day. The chlorophyll‐a concentration was found to increase by a factor of between 3 and 6 depending on the season, while the biomass load increased by a factor of up to 18. The concentrations of dissolved silicate and dissolved total phosphate behaved oppositely to this development, while the levels of particulate bound nutrients rose accordingly. Depending on the season, 6…23% of the total bound nitrogen was found to be removed from the river by denitrification. The river Saale contains the highest load of nutrients of all the tributaries. At the end of the investigated reach, algae biomass accounts for as much as 75% of the POC.</jats:p>