Influence of environmental conditions, bacterial activity and viability on the viral component in 10 Antarctic lakes.
The influence of biotic and environmental variables on the abundance of virus-like particles (VLP) and lysogeny was investigated by examining 10 Antarctic lakes in the Vestfold Hills, Antarctica, in the Austral Spring. Abundances of viruses and bacteria and bacterial metabolic activity were estimated using SYBR Gold (Molecular Probes), Baclight (Molecular Probes) and 6-carboxy fluorescein diacetate (6CFDA). Total bacterial abundances among the lakes ranged between 0.12 and 0.47 x 10(9) cells L(-1). The proportion of intact bacteria (SYTO 9-stained cells) ranged from 13.5% to 83.5% of the total while active (6CFDA-stained) bacteria ranged from 33% to 116%. Lysogeny, as determined with Mitomycin C, was only detected in one of the lakes surveyed, indicating that viral replication was occurring predominantly via the lytic cycle. Principal component analysis and confirmatory correlation analysis of individual variables showed that high abundances of VLP occurred in lakes of high conductivity with high concentrations of soluble reactive phosphorus and dissolved organic carbon. These lakes supported high concentrations of chlorophyll a, intact bacteria, rates of bacterial production and virus to bacteria ratios. Thus, it was suggested that viral abundance in the Antarctic lakes was determined by the trophic status of the lake and the resultant abundance of intact bacterial hosts.
Säwström
Christin
C
Department of Ecology and Environmental Science, Climate Impacts Research Centre (CIRC), Umeå University, Abisko, Sweden. christin.sawstrom@emg.umu.se
Pearce
Imojen
I
Davidson
Andrew T
AT
Rosén
Peter
P
Laybourn-Parry
Johanna
J
D000864:Antarctic Regions; D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism / Q000821:virology; D001435:Bacteriophages / Q000254:growth & development* / Q000302:isolation & purification / Q000502:physiology; D005452:Fluoresceins / Q000378:metabolism; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology* / Q000821:virology*; D008242:Lysogeny; D015335:Molecular Probes; D009930:Organic Chemicals / Q000378:metabolism; D025341:Principal Component Analysis; D014771:Virion / Q000254:growth & development
D005452:Fluoresceins; D015335:Molecular Probes; D009930:Organic Chemicals; C103389:SYTO 9