THE EFFECT OF AN UPWELLING EDDY ON MARINE VIRUSES

picture of Sarah Schwenck presenting his/her poster: THE EFFECT OF AN UPWELLING EDDY ON MARINE VIRUSES

Sarah Schwenck , Jennifer R. Brum, Matthew B. Sullivan

THE EFFECT OF AN UPWELLING EDDY ON MARINE VIRUSES

At 107 per milliliter, viruses are the most abundant biological entities in the ocean. These viruses can kill their hosts, transfer genetic material between hosts, and express genes during infection that alter their host’s metabolism. Marine viruses predominantly infect the most abundant living organisms in the ocean: bacteria and phytoplankton. Upwelling eddies are oceanographic features that mix deep nutrient rich seawater into sunlit surface waters, promoting primary production, increasing phytoplankton and bacterial concentrations, and altering community structure. Thus, we predicted that an upwelling eddy would concomitantly increase viral abundance and alter the structure of the viral community. To test this hypothesis, we collected samples at both the surface and deep chlorophyll maximum (DCM) from four stations along a transect that followed the course of an upwelling eddy spun off southern Africa as it dissipated traversing the Atlantic Ocean. Virus concentrations were determined with epifluorescence microscopy while viral morphological characteristics such as morphotype, capsid width, and tail length were examined using transmission electron microscopy. Virus concentrations increased in the latter portion of the transect, but were not correlated with changes in chlorophyll concentration. Morphologically, there was a slight increase in myoviruses along the transect, but non-tailed viruses remained steadily dominant. There were also significant differences in average viral capsid width, but they were not correlated with chlorophyll concentrations. Additionally, comparison of viral capsid width distributions showed that the viral assemblage was highly similar along the transect. Together these results suggest that upwelling eddy waters did not significantly affect ocean viral assemblages; however, a more detailed follow-up metagenomic analysis of these same viral assemblages may reveal differences not seen at the morphological level.

 

Funding was provided by the Gordon and Betty Moore Foundation (grant #4560900) and Howard Hughes Medical Institute (grant #52006942).

Conference Home | List of Abstracts | Photo Gallery