Dataset: ETNP Viral Morphology

Detailed protocols, including suggestions from the scientific community, are published on the lab website at https://u.osu.edu/viruslab/protocols/ and maintained on protocols.io at https://www.protocols.io/workspaces/sullivan-lab.

Samples were collected from the Eastern Tropical North Pacific oxygen minimum zone region (ETNP OMZ) during the OMZ Microbial Biogeochemistry Expedition cruise (R/V NewHorizon,13-28 June 2013). Seawater was collected from 16 depths spanning the mixed layer, oxycline, OMZ core, and below the OMZ. Collections were made using Niskin bottles on a rosette. Samples were preserved with EM-grade glutaraldehyde (2% final concentration), flash-frozen in liquid nitrogen and stored between -72 °C and -80 °C until analysis.

Viruses were deposited onto TEM grids with an air-driven ultracentrifuge (Airfuge CLS, Beckman Coulter, Brea, CA, USA) and positively stained by immersion in 2% uranyl acetate (Ted Pella, Redding, CA, USA). Prepared grids were examined using a transmission electron microscope (Phillips CM12, FEI, Hilsboro, OR, USA) with 100 kV accelerating voltage. Micrographs of 100 viruses per sample were collected using a Macrofire Monochrome CCD camera (Optronics, Goleta, CA, USA). Viruses were classified as myoviruses, podoviruses, siphoviruses or non-tailed viruses based on their morphology. Viral capsid diameters and tail lengths were measured using ImageJ software (US National Institutes of Health, Bethesda, MD, USA).