Viral lysis, flagellate grazing potential, and bacterial production in Lake Pavin.

Abundances of different compartments of the microbial loop (i.e., viruses, heterotrophic bacteria, nonpigmented nanoflagellates, and pigmented nanoflagellates), bacterial heterotrophic production (BHP), viral lysis, and potential flagellate grazing impacts on the bacterial assemblages were estimated during a short-term study (24 h) conducted in June 1998 in the epilimnion (5 m) and metalimnion (10 m) of a moderate-altitude oligomesotrophic lake (Lake Pavin, France).

Does storage affect epifluorescence microscopic counts of total bacteria in freshwater samples?

Preservation with formalin and storage at 4 degrees C of freshwater samples, associated with sonication before counting, proved to be efficient for a few days of storage (no differences with the initial cell count within 7 d of storage); after 8 months, 95% of the initial count was preserved. This procedure always gave higher counts than those obtained from the freezing technique of filter storage at -18 degrees C after sample filtration.