Effect of preliminary filtration on the functional characteristics of bacterioplankton from Lake Khanka

The dependence of the functional characteristics of bacterioplankton from t he loess of Lake Khanka on the pore size of filtering materials was investi gated. Soluble organic matter (SOM), bacteria, and bacterial consumers adso rbed on particles suspended in the lake water were found to filter differen tly depending on the pore size of the filtering material. Filters with pore size 4.5 mum (filters II) retained up to 20% of SOM and 20-30% of bacteria l cells. Filters III with pore size 2.87 mum retained almost 50% of SOM and about 40% of bacteria. The double layer of gauze no. 72 (referred to as fi lter I) with pores size 40 mum was unable to completely retain bacterial co nsumers. In the case of filtrates I and LT, the generation time of bacterio plankton decreased with its increasing average daily concentration. In the case of filtrate III, the generation time of bacterioplankton was minimum a nd did not depend on its concentration. Oxygen consumption rates per one ba cterial cell and per unit biomass in filtrates increased with decreasing po re size of the filters through which they had passed. The bacterial biomass and oxygen consumption rate increased exponentially in filtrates LU and lo garithmically in filtrates I.