Viruses are an important top-down control on microbial communities, yet their direct 11 study in natural environments has been hindered by culture limitations [1][2][3] . The advance of 12 sequencing and bioinformatics over the last decade enabled the cultivation independent 13 study of viruses. Many studies focus on assembling new viral genomes 4-6 and studying viral 14 diversity using marker genes amplified from free viruses with POLA being the most impacted and SPOT resembling open ocean conditions. In all of these 33 sites free virus-like particles outnumber bacteria and archaea roughly 10:1 (sup. fig. 1). We 34 examined only the 0.2-1 µm size-fraction, which includes most bacteria, archaea and some 35 picoeukaryotes. Via assembly of metatranscriptomes, we obtained 1455 contigs longer than 5 kb 36 of which 57 (3.9%) were characterized as viral using virSorter and virFinder (see methods). 37Additionally, a cross-assembly of the metatranscriptomic viral contigs with metagenomes of the 38 same samples (N=12) yielded 9 more contigs (mean length 26,563 bp) characterized as viral. 39Most of the contigs represent dsDNA viruses (N= 65) as apparent from their presence in 40 metagenomes, but one appears to be an RNA virus possibly infecting a eukaryotic host. This 41 contig contained an RNA-dependent-RNA-polymerase whose nearest match in NCBI non-42 redundant database was marine Antarctic phytoplankton RNA virus PAL_E4 9 . These 66 viral 43 contigs revealed varied patterns of presence (in metagenomes) and activity (in 44 metatranscriptomes) in the three sites over a year (fig.
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