Isolation of a Cohort of Giant Viruses From Above the Arctic Circle in Northern Norway

Viruses are the most abundant biological entities on Earth. Metagenomic data indicates a higher viral abundance of viruses of unicellular eukaryotes in the polar regions, information still not matched by broad isolation efforts using samples collected in these regions. Here we describe a prospection effort using diverse samples collected above the Arctic circle, including freshwater and marine samples from urban areas, deep-sea hydrothermal vents and sea ice samples from the Nansen Basin. We isolated 10 giant viruses capable of infecting Acanthamoeba spp., five representing the Marseilleviridae family and five representing the Mimiviridae family. These viruses are the northernmost isolates found so far in the Nordic countries and consist of a unique cohort of Arctic viruses that differs geographically and temporarily from a cohort already described from the Siberian permafrost. Despite an apparent viral diversity in the samples, the uniqueness of the samples themselves and the use of additional non-amebozoan strains as hosts, our viruses are still representatives of known viral families. In conclusion, here we show the isolation of giant viruses in Northern Norway and highlight the potential host bias towards Acanthamoeba in giant virus prospection, indicating the need to break this bias to diversify the isolation of environmental viruses.