Name: Dawn Goldsmith

Email: dawn.goldsmith@gmail.com

Author: Dawn B. Goldsmith1*, Rachel Parsons2, Kimberly Pause Tucker1, Craig Carlson3, Mya Breitbart1

Author affiliation: 1. University of South Florida, College of Marine Science, St. Petersburg, FL 2. Bermuda Institute of Ocean Sciences, St. George?s, Bermuda 3. University of California at Santa Barbara, Santa Barbara, CA

Abstract title: Abundance and Diversity of Viruses Throughout the Water Column in the Northwestern Sargasso Sea

Absstract:

Viruses play a key role in the marine environment because they regulate the transfer of energy between trophic levels and influence global carbon and nutrient cycles. Studies have revealed tremendous diversity of marine viruses, but most previous studies take a snapshot of the viral community, rather than examining how viral communities change either in time or in space. The goal of this project is to gain a better understanding of the abundance and diversity of viruses in the Northwestern Sargasso Sea. The study site chosen for this project is the Bermuda Atlantic Time Series site, approximately 80 km southeast of Bermuda. Integrating with the Bermuda Atlantic Time Series allows us to analyze the viral parameters in the context of a long history of chemical and biological measurements at this site. This study examines viral abundance throughout the water column on a monthly basis using epifluorescent microscopy. A recurring seasonal pattern of viral abundance is seen: virus concentrations are low and uniformly distributed in the mixed layer during the winter, but a strong subsurface maximum in viral abundance develops at 80-100 meters each spring/summer. Diversity analyses have focused on determining whether the viral community composition is constant throughout the water column or viruses have depth-specific distributions. Viral diversity was examined through analysis of the T4-like myophage, the T7-like podophage, and a single-stranded DNA phage recently discovered to be abundant in the Sargasso Sea. Myophage and Podophage are present both at the surface and at 100 meters depth, with significant overlap in the diversity of each group between the two depths. In contrast, the single-stranded DNA phage are much more narrowly distributed, and can only be detected between 80 and 120 meters depth. Future work will determine whether these patterns in viral diversity are maintained throughout repeated seasonal cycles.