design: Shotgun metagenomic sequencing was conducted on environmental water samples from the Eastern North Pacific to investigate microbial functional diversity, with a focus on archaeal and bacterial vitamin B1 cycling in oxygen minimum zones. DNA was extracted using phenol:chloroform:isoamyl alcohol and purified with AMICON-4 columns (Millipore). Libraries were prepared with the Kapa HyperPrep kit (Roche) and sequenced on an Illumina NovaSeq 6000 S2 platform using 2  150 bp paired-end reads.