Researchers have collected ocean water samples from around the world and discovered a huge number of unknown RNA viruses: this will help expand ecological research and change our knowledge of how these viruses evolved.

The authors of the new work combined the analysis of machine learning with traditional methods of studying evolution and identified 5,500 new types of RNA viruses. They represent all five known types of RNA viruses. During the work, the researchers examined 35,000 water samples.

The most extensive collection of RNA viruses belongs to the type that the authors proposed to call Taraviricota. Its representatives are found in almost all samples.

RNA viruses are certainly important, but we usually study only a tiny fraction of them – a few hundred – that harm people, plants and animals. We would like to systematically study them on a large scale.

Matthew Sullivan is professor of microbiology at The Ohio State University.
Microbes make a significant contribution to the development of all life on the planet, and the viruses that infect or interact with them have a different effect on the functions of microorganisms. These types of viruses are believed to have three main functions: kill cells, change how infected cells manage resources, and transfer genes from one host to another.

It is important to study the diversity and abundance of viruses in the oceans, the researchers say, to help explain how marine microbes influence ocean adaptation to climate change. The oceans absorb half of the carbon dioxide that humans produce from the atmosphere, and previous research by this group has shown that marine viruses are the “regulator” that is responsible for how carbon accumulates in the ocean.

During the new work, the group found hundreds of new RNA viruses that belong to existing types. But the analysis also revealed thousands more species, which they grouped into five new phyla: Taraviricota, Pomiviricota, Paraxenoviricota, Wamoviricota, and Arctiviricota.