Viral lysis of marine bacterioplankton: Implications for organic matter cycling and bacterial clonal composition

Viruses are responsible for a large part of bacterio-plankton mortality in marine waters. They regulate population dynamics and diversity of the bacterial community and influence carbon dynamics via the release of bacterial cell contents. A large fraction of viral lysates is rapidly consumed by bacteria making the transfer of matter from bacteria via dissolved organic matter (DOM) and back to bacteria (the “Viral loop”) an efficient pathway. Viral infection has extensive and complex effects on bacterial species and clonal composition. The general perception of virus-bacteria interactions as a simple predator — prey interplay between lyric viruses and their specific hosts is a crude simplification. For instance, acquisition of resistance to viral infection is a common defense mechanism. In addition, lysogenic bacteria and broad-host range viruses are occasionally important; illustrating that lytic infection of a specific host is one of many viral effects on the bacterial community. In this minireview, ideas emerging from the most recent literature concerning virus-bacteria dynamics in marine plankton are synthesized. The significance of bioavailable and refractory lysis products for the DOM dynamics in marine waters is discussed along with the potential effects of viruses on bacterioplankton clonal composition (resistant vs. sensitive bacteria), diversity, and distributional patchiness.