Metavirome analysis of virus removal during Oikopleura dioica feeding

We have previously demonstrated that the planktonic tunicate Oikopleura dioica is able to efficiently remove the Emiliania huxleyi virus (EhV) from seawater during normal filter feeding activity in controlled laboratory incubations. In this study, we expand our findings to show that O. dioica efficiently removes EhV from complex assemblages of naturally co-occurring viruses that arise during an induced E. huxleyi bloom in seawater mesocosms. Furthermore, metavirome analysis of control and O. dioica-exposed virus assemblages indicate that the clearance effect provided by O. dioica feeding applies to large dsDNA viruses in general and is not specific to EhV. These results strengthen our conceptual model that filter-feeding mesozooplankton such as O. dioica play important but poorly understood roles in mediating marine virus ecology.