A dilution technique for the direct measurement of viral production: a comparison in stratified and tidally mixed coastal waters.
The abundance of heterotrophic bacteria and viruses, as well as rates of viral production and virus-mediated mortality, were measured in Discovery Passage and the Strait of Georgia (British Columbia, Canada) along a gradient of tidal mixing ranging from well mixed to stratified. The abundances of bacteria and viruses were approximately 10(6) and 10(7) mL(-1), respectively, independent of mixing regime. Viral production estimates, monitored by a dilution technique, demonstrated that new viruses were produced at rates of 10(6) and 10(7) mL(-1)h(-1) across the different mixing regimes. Using an estimated burst size of 50 viruses per lytic event, ca. 19 to 27% of the standing stock of bacteria at the stratified stations and 46 to 137% at the deep-mixed stations were removed by viruses. The results suggest that mixing of stratified waters during tidal exchange enhances virus-mediated bacterial lysis. Consequently, viral lysis recycled a greater proportion of the organic carbon required for bacterial growth under non-steady-state compared to steady-state conditions.
Wilhelm
S W
SW
Department of Microbiology, The University of Tennessee, Knoxville, TN, USA.
Brigden
S M
SM
Suttle
C A
CA
D001419:Bacteria; D011157:Population Dynamics; D014780:Viruses; D014871:Water Microbiology; D014872:Water Movements