Dynamics of the cyanobacterial water bloom with focus to Microcystis and its relationship with environmental factors in Brno reservoir

Abstract

Our paper brings new information about long-term changes of the phytoplankton communities in the Brno reservoir with the focus on the Microcystis abundance using the semi-monthly monitoring data covering the period 2006–2012. The main aim is to extract from this long-term data set differences in number of Microcystis cells depending on environmental factors. The development of cyanobacteria in Brno reservoir is caused by excessive phosphate loading from wastewater treatment facilities upstream and from non–point sources along the Svratka river. It focuses management effort on upstream controls of reservoir condition. High abundance in millions of cyanobacteria cells in 1ml observed in Brno reservoir before was reduced to values in the order of thousands cells in 1ml in last two years through a combination of measures (liming, precipitation of phosphorus on inflow, aeration and destratification). Phytoplankton composition was also changed and at the expense of cyanobacteria promoted the development of green algae and diatoms.