Previously collected ice cores taken from a Tibetan glacier have revealed 28 new genera of viruses [phys.org] according to researchers from Ohio State University and Lawrence Berkeley National Laboratory.
A genus (plural genera) in biology encompasses multiple species. For example Lions and Tigers (not bears) belong to the genus Panthera
The ice cores had not been protected from surface contamination when collected from the from the Guliya ice cap (northwestern Tibetan Plateau, China), so it was first necessary to establish "ultra-clean microbial and viral sampling procedures for glacier ice."
To ensure a pristine sample, the researchers, working in a freezer, first cut off some of the outer layer of each core sample. Each of the samples was then washed with ethanol to melt off approximately 0.2 inches of ice. Each was then washed again with sterile water to melt off another 0.2 inches of ice. The team also created test samples by repeating the same cleaning procedure on ice cores that had first been covered with known viruses and bacteria. The samples that remained were then deemed pristine and ready for study.
The study of the cores revealed a total of 33 groups of viruses with the majority previously unseen. The researchers note the importance of the work exposing the potential of melting glaciers to unleash deadly viruses.
Zhi-Ping Zhong et al. Glacier ice archives fifteen-thousand-year-old viruses, bioRxiv (2020). DOI: 10.1101/2020.01.03.894675 [doi.org]