The effect of "top down" regulation on the bacterioplankton structure and metabolic activity

The aim of the study is to explain the effect of the "top down" regulation of the trophic pyramid on the bacterioplankton structure and metabolic activity. The "microcosm" type study included experimental arrangements in which lacustrine water was pre-filtered in three variants. A high dynamics of bacterioplankton count was observed in the system without the pressure from flagellate, while the stability of the system for the parameter was typical of water pre-filtered through a 30 μm pre-filter. The highest proportion of CTC+ metabolically active bacteria in the total number of bacterioplankton was observed in the variant with the preserved flagellate fraction.