Marine Viruses and Their Role in Marine Ecosystems and Carbon Cycling.

Marine viral ecology emerged as a distinct discipline approximately 25 years ago. Despite significant progress, direct assessments of viral impacts on carbon flux remain scarce. Here, we integrate recent advances and knowledge gaps in marine viral ecology and a comprehensive conceptual viral-engine framework, highlighting the various ways in which viruses play a fundamental role in shaping marine ecosystem dynamics. Moreover, we present a meta-analysis of virus-mediated microbial mortality rates to examine the role of viruses in driving seasonal and global patterns in microbial biomass. We illustrate how viruses fundamentally shape marine ecosystem dynamics and serve as key drivers of microbial turnover, nutrient recycling, and global carbon cycling, positioning them as an engine driving oceanic biogeochemical processes.