Marine viruses

With an estimated global abundance of 10³⁰, viruses represent the most abundant biological entities in the ocean. There is emergent awareness that viruses represent a driving force not only for the genetic evolution of the microbial world but also the functioning marine ecosystems. Culture studies advance our understanding how viruses regulate host population dynamics, but retrieving virus and host in pure culture can be difficult. Recent developments in high-throughput sequencing provide insights into the diversity and complexity of viral populations. This chapter describes current milestones in the burgeoning field of marine viral ecology, including the different aspects of marine viral action, viral diversity, ecological and biogeochemical implications of marine viruses, the cultivation of virus-host systems, and biotechnological applications of these astonishing microorganisms.