Bacteriophage Distributions and Temporal Variability in the Ocean's Interior

Area of Science:

• Marine microbiology
• Virology
• Oceanography

Background:

• Bacteriophages are abundant in the ocean, but their temporal and spatial dynamics are not fully understood.
• Understanding marine viruses is crucial for comprehending microbial community dynamics and biogeochemical cycles.

Purpose of the Study:

• To investigate the spatiotemporal distribution and characteristics of double-stranded DNA (dsDNA) phages in the North Pacific Subtropical Gyre.
• To explore viral life histories and host-environment interactions in the open ocean water column.

Main Methods:

• Conducted a 1.5-year metagenomic time-series survey of dsDNA phages.
• Collected samples from depths of 25 to 1,000 meters in the North Pacific Subtropical Gyre.
• Identified viral gene families and assembled viral genomes from metagenomic data.

Main Results:

• Identified an estimated 172,385 viral gene families and 129 abundant viral genotypes.
• Observed distinct phage population structures with strong depth-specific distributions.
• Found mesopelagic phages differed from surface phages in diversity, gene content, and temporal persistence.

Conclusions:

• Phage populations exhibit significant temporal persistence and strong depth structuring, mirroring bacterial distributions.
• Lysogeny appears more prevalent in mesopelagic waters compared to surface waters.
• Depth-dependent differences in host and phage strategies shape marine virus ecology.