Phytoplankton diversity, abundance, and community composition change through the seasons, driven by variations in environmental conditions and biological processes. Haptophytes are an important component of this community, contributing to 30-50 % of the photosynthetic standing stock (biomass) in the photic layer of the world’s oceans. To this date, only viruses infecting nine marine haptophyte species has been isolated and characterized. Of these, cultured viruses are only described to infect members of Prymnesiophyceae, whereas no viruses have been described infecting members of the class Pavlovophyceae. This group is both of economical but also ecological importance as they are abundant in coastal marine-brackish water but also in intensive use in aquaculture. In this Aurora project we will aim to obtain cultures of Pavlovophycea AC35 and viruses, through exchange of knowledge by shorter visits between the two groups Unicaen and UiB. A preliminary characterisation of the virus- host systems will be performed as a part of a master project at Unicaen. The master student will have a long visit (5-6 months) at UiB to learn working with algal viruses and their hosts. If success we will have a short visit in the fall 2023 to plan for future grant applications where our ultimate goal is to gain novel information about the ecology and evolution of this newly isolated host virus system.