Viral metagenomes from the Sargasso Sea (BIOS-SCOPE cruise AE1712)

In the summer months, the waters of the Sargasso Sea are nutrient-limited and strongly stratified, serving as a model system for the predicted warmer and nutrient limited oceans of the Anthropocene. The dominant microorganisms of surface waters are key drivers of the global carbon cycle. However, the viruses of the Sargasso Sea that shape these host communities and influence host biogeochemical function are not well understood. Here, we apply a hybrid sequencing approach that combines short- and long reads to survey Sargasso Sea phages via viral metagenomics at the viral maximum (80m) and mesopelagic (200m) depths. Taxonomically, we identified 2,301 Sargasso Sea phage populations (~species-level taxonomy), and co-analysis with Global Ocean viral metagenomes indicated that approximately a quarter of were only identifiable in this subtropical ocean gyre, whilst 177 Sargasso Sea phage genera were not represented in phage isolate databases.