Seasonal Changes of Bacterioplankton in a Reservoir Related to Algae. I. Numbers and Biomass

A reservoir for drinking water supply was studied at 10 day intervals for one season. Changes in bacterial microscopic counts and chlorophyll and algal biomass showed a similar pattern. Bacterial peaks usually lagged slightly behind the algal maxima. Average volumes of bacterial cells, corrected for shrinkage, were mostly lower than 0.2 μm³. The average concentration of bacterial C in water was estimated to be 18 μg μg 1 ⁻¹ (from a volume biomass of 0.09 mm³ per litre). Several years' fluctuations in bacterial numbers were compared with hydrological data and phyto- and zooplankton changes.