Viral Diversity and Mortality of Phyto- and Bacterioplankton in the Arctic Ocean

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Proposal No: OPP-9623130 Principal Investigator: Azam, Farooq ABSTRACT Viral Diversity and Mortality of Phyto-and Bacterioplankton in the Arctic Ocean This proposal requests funding to investigate the magnitude and variability of bacteria and phytoplankton mortality due to viral attack in the Arctic Ocean. Viral distribution, abundance and variations in composition and diversity of viruses in the study area will also be investigated. In addition to the examination of natural viral communities, samples will be screened for the presence of sewage-derived bacterial viruses as an indicator of the penetration of terrestrial biological pollutants into the Arctic Ocean. Collection, fixation and concentration of sea water samples will be accomplished at sampling sites by deployment from a U.S. Navy submarine. Subsequent analyses will be conducted in the laboratory. Total counts of viruses and the frequency of viral infection in phytoplankton and bacteria will be determined by electron microscopy on fixed samples. To examine natural community diversity, concentrates of viruses will be purified and subjected to pulsed-field gel electrophoresis to separate viral DNA based on genome size. From the number, positions, and staining intensity of different bands, the diversity, genome sizes, and abundance of viruses in each sample will be estimated. Sewage derived viruses will be detected by amplification of target DNA sequences using the polymerase chain reaction and by plaque assay. Through coordination with other researchers, viral abundance, the frequency of viral infections, and viral community diversity will be related to hydrographic and biological variables in order to determine those which may be important in regulating viral propagation.