Surface water sample (10 L) concentrated by dead-end hollow fibre ultrafiltration (R180 Inuvai), followed by secondary concentration using Amicon Plus-15 centrifugal ultrafiltration units (10 kDa cutoff). Total DNA/RNA extracted from 1 mL of concentrate using the Quick-RNA Viral Kit (Zymo Research). Strand-specific total RNA libraries prepared using Illumina TruSeq Stranded Total RNA library preparation. Paired-end sequencing performed on an Illumina NovaSeq 6000.