Viruses never cease to fascinate and frigthen us because of their pathogenic nature for plants and animals. In seas and oceans, they are major players in the functioning of ecosystems. Viruses are the smallest, most abundant, and most diverse biological entities known to date in marine environments, where they perform multiple functions. In addition to their role in cellular mortality and the redistribution of matter, viruses are also powerful drivers of the evolution of their hosts and represent a major source of genetic diversity, offering rich opportunities for discoveries in both fundamental and applied research. The aim of this book is to highlight an invisible biological community that is essential for understanding and explaining how the oceans function. The authors, specialists in the ecology and evolution of aquatic viruses, show how viruses regulate microbial ecosystems—the foundation of oceanic food webs—and how their activity could, under certain circumstances, influence the climate.

This book is intended for students in life and earth sciences, teachers, researchers, and academics, as well as for the general public interested in the subject of viruses and the oceans.