Faculty of 1000 review:
This thorough study of viral dynamics in marine sediments constitutes a major advancement in understanding the roles of viruses in microbial communities and ecosystems. The picture emerging from more than 200 sediment samples taken in four distinct sea basins is that viral production and virus-mediated bacterial mortality are extraordinarily high and increase with water depth, thus extending the now well established significance of virioplankton to marine sediments, especially in the deep sea, where a very large fraction of the Earth’s prokaryotes resides. Similar observations have been made in smaller-scale studies of other marine sediments; however, the results contrast sharply with the lack of significant directly detectable viral infection in freshwater benthic habitats, which had fostered speculation that the roles of viruses in benthic systems could be far less important than in pelagic environments.