SPATIOTEMPORAL VARIABILITY AND VERTICAL TRANSPORT OF GIANT VIRUSES IN THE NORTH PACIFIC SUBTROPICAL GYRE

Nucleocytoplasmic large DNA viruses (giant viruses) are widespread in marine environments, infecting a broad range of eukaryotes and regulating microbial population dynamics and biogeochemical cycling. This study is the first to integrate metagenomic datasets from both the water column and seafloor sediment to assess the vertical transport of giant viruses and their association with carbon export. We analyzed metagenomic samples from the Hawaii Ocean Time-series (HOT), focusing on long-term metagenomic datasets (n=861) collected over six years across 15 depths from 5-4000m, with sediment trap samples also collected at 4000m seafloor. We report for the first time the vertical transport of several giant virus species, including algae infecting Phaeocystis globosa virus and Chlorella virus XW01, and their correlation with carbon export from the water column to abyssal depth. Furthermore, we postulate depth-specific adaptations in giant viruses to influence host cell metabolic processes, such as photosynthesis, carbon, sulfur, and nitrogen metabolism. Phylogenetic analysis of 38 metagenome-assembled genomes revealed the presence of three different families of giant viruses, dominated by the protist-infecting Mimiviridae. Spatiotemporal analysis of these genomes uncovered distinct distributions unique to their taxonomic group. Overall, our findings identified key giant viruses associated with vertical transport and carbon export flux in the oligotrophic ocean. Additionally, we observed notable metabolic capacities and a unique spatiotemporal distribution of these viruses.

Presentation Preference: Oral

Primary Presenter: Md Moinuddin Sheam, University of North Carolina at Charlotte (msheam@uncc.edu)

Authors:

Md Moinuddin Sheam, University of North Carolina at Charlotte  (msheam@uncc.edu)

Elaine Luo, University of North Carolina at Charlotte  (elaine.luo@charlotte.edu)