Viral Lysis, Flagellate Grazing Potential, and Bacterial Production in Lake Pavin

• Published in: Microbial ecology Vol. 45; no. 2; pp. 119 - 127
• Main Authors: BETTAREL, Y, AMBLARD, C, SIME-NGANDO, T, CARRIAS, J.-F, SARGOS, D, GARABETIAN, F, LAVANDIER, P
• Format: Journal Article
• Language: English
• Published: New York, NY Springer-Verlag New York Inc 01.02.2003; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Animal, plant and microbial ecology; Animals; Bacteria; Bacteria - growth & development; Bacteria - virology; Bacteriophages; Bacterioplankton; Biodiversity and Ecology; Biological and medical sciences; Biotechnology; Cell Count; Ecosystem; Environmental Sciences; Epilimnion; Eukaryota - growth & development; France; Fresh Water; Freshwater; Fundamental and applied biological sciences. Psychology; Grazing; Lakes; Metalimnion; Microbial ecology; Microscopy, Electron; Mission oriented research; Mortality; Plankton; Predation; Prospectives; T tests; Various environments (extraatmospheric space, air, water); Viruses; Viruses - growth & development; Water Microbiology; France; Europe; France, Auvergne, Pavin L; Short term; Biotope; Mortality; Loss; Transmission; Freshwater environment; Lysis; Lakes; Pigments; Bacteria; Infected cell; Predation; Ecological abundance; Altitude; Europe; France
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-002-1016-1

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). Viral and bacterial abundances were higher in the metalimnion than in the epilimnion, whereas pigmented and nonpigmented nanoflagellates were more numerous in the epilimnion. The control of the BHP due to viral lysis (determined by examination of viral-containing bacteria using a transmission electron microscope) was significantly higher in the meta- (range = 6.0-33.7%, mean = 15.6%) than in the epilimnion (3.5-10.3%, 6.4%). The same was for the losses of BHP from the potential predation by nanoflagellates which ranged from 0.5 to 115.4% (mean = 38.7%) in the epilimnion, and from 0.7 to 97.5% (mean = 66.7%) in the metalimnion. Finally, estimated viral mediated mortality rates from the percentage of visibly infected cells and potential nanoflagellate grazing rates based on assumed clearance rates suggest that flagellates consumed a larger proportion of bacterial production than was lost to viral lysis.