About the project
Appendicularians (Chordata:Tunicata) are cosmopolitan pelagic gelatinous zooplankton in Norwegian coastal and offshore marine ecosystems. These small animals acquire food through the production of filter houses that function by both trapping and concentrating food particles. The effective pore size of these houses can be as small as 0.1-0.2 µm, making these animals very efficient at capturing sufficient nutrition in low productivity environments. Marine viruses are critical components of the marine microbial food web, whose lysis activity drives global elemental cycles in addition to regulating the diversity of marine microbial assemblages. We conducted a pilot experiment in order to determine whether the appendicularian O. dioica is able to remove the marine microalgal viruse Emiliania huxleyi virus (EhV, 160-180 nm in diameter) from seawater. Our results show that O. dioica can efficiently reduce EhV titres in seawater, and that these viruses can be "trapped" in O. dioica houses and faecal pellets that sink to the sea floor. This vertical transport of virus particles may have significant consequenes for microbial diversity in the ocean by altering the size and/or diversity of virus assemblages. Furthermore, the interaction between O. dioica and EhV represents a mechanism by which virus particle survival may be enhanced through the "protection" of viruses in bottom sediments. Our ongoing research on this topic seeks to describe all aspects of this interaction in order to better understand this unique link between the classical food web and the marine microbial food web.