Fig. 1.

Assessment of viral community structure and activity after a ¹⁸O-water incubation in Arctic peat soils. A Viral sequences were identified from 23 samples grouped by two treatments (natural abundance water “H₂¹⁶O,” and heavy water “H₂¹⁸O”) and two time points: 184 days and 370 days. The number of replicates is indicated in parentheses. Relative abundances of all 332 vOTUs identified in the peat soils, clustered by abundances in each treatment/timepoint. B Relative abundances of 243 vOTUs considered “active” due to DNA ¹⁸O enrichment patterns. Relative abundance for each vOTU (illustrated by blue gradient) was normalized by metagenome size (total base pairs) and contig length, and reads were mapped to the contig if they shared ≥90% average nucleotide identity and covered ≥75% of the contig. C Diversity metrics for the 243 active vOTUs. Box plots show the median, upper, and lower quartile range, and the variance among the samples. Difference between midyear and full-year samples was determined with a t test and significance denoted by an asterix (p <0.05)