Viruses in the sediments around the trenches harbor diverse survival mechanisms.

Deep-sea trenches are the deepest and most isolated environments in the global ocean but the diversity and adaptation of the viral communities remain poorly characterized. In this study, 5563 viral operational taxonomic units (vOTUs) were identified from sediments of the Yap Trench and Western Caroline Basin. More than 99% of these vOTUs could not be assigned to known viral families and showed limited similarity to sequences in current global viral databases, indicating substantial novelty. Viral community composition and diversity were found to significantly vary with water depth. The vOTUs also encoded a diverse range of functional genes possibly related to their ability to survive in extreme deep-sea sediments, including genes involved in lipid metabolism, DNA modification, and immune evasion. The results show that deep-sea trench sediments contain highly distinct viral communities structured by depth-associated environmental variations.