Viral community of basalt-hosted crustal fluids from the Juan de Fuca Ridge flank

Viral metagenomes generated from pristine, geothermally-heated crustal fluid, collected at Circulation Obviation Retrofit Kit (CORK) sites installed in IODP borehole U1362A at the Juan de Fuca Ridge Flank. Samples were collected with a large viral in-situ sampler, consisting of two filters in tandem, a 0.2 micron capsule filter upstream of a 100 kDa nominal molecular weight cutoff filter. Samples were physically fractionated into buoyant density fractions using a continuous cesium chloride (CsCl) gradient.