Scientists have reported that thousands of mysterious viruses recently discovered are lurking in the world’s oceans. Among these, the focus is on RNA viruses that infect other marine organisms.
A new study published in the journal Science concentrates on RNA viruses, a molecule that is a “relative” of DNA.
RNA viruses are abundant in the ocean. (Image: The Economic Times/iStock)
RNA viruses are prevalent in human diseases. For instance, coronaviruses and influenza viruses are both based on RNA. However, when it comes to RNA viruses in the ocean, scientists are just beginning to explore the diversity that can be found and the range of hosts they can infect.
Dr. Guillermo Dominguez-Huerta, a viral ecology scholar at Ohio State University (OSU) and a co-author of the study, told Live Science: “Based on our new research, we are confident that most RNA viruses in the ocean are infecting eukaryotic organisms.”
Eukaryotic organisms are those with complex cells that contain their genetic material within a nucleus.
The viral hosts – specifically fungi and protists, including algae and amoebae – pull carbon dioxide from the atmosphere and thus affect the amount of carbon stored in the ocean.
Image of RNA viruses – (Image: ALPES HOLIDAY)
According to Steven Wilhelm, the principal investigator of the Aquatic Microbial Ecology Research Group at the University of Tennessee Knoxville, “By infecting these organisms, RNA viruses can influence how carbon flows through the ocean.”
In early 2022, Dominguez-Huerta and his colleagues reported discovering over 5,500 previously unidentified RNA viruses in the world’s oceans.
The research team analyzed 35,000 water samples collected from 121 locations across the five oceans as part of the Tara Oceans Consortium, a global ongoing study aimed at examining the impact of climate change on the oceans.
These water samples were filled with plankton – tiny organisms that drift with the currents and often serve as hosts for RNA viruses.
To detect the viruses in these plankton, researchers screened all RNA in the cells of the plankton for a specific genetic code known as the RdRp gene.
Scientists identified virus communities that could be categorized into four main regions: Arctic, Antarctic, Temperate, and Tropical. Interestingly, the diversity of viruses appears to be highest in polar regions, despite having a greater variety of hosts to infect in warmer waters.
Co-author Ahmed Zayed, a research scientist in the microbiology department at OSU, stated: “When it comes to diversity, viruses don’t really care how cold the water is. This finding suggests that near the poles, many types of viruses are competing for the same host.”
After identifying potential hosts for ocean-infecting viruses, the research team determined that approximately 1,200 viruses could be involved in the process of “exporting” carbon. This is the process where carbon is extracted from the atmosphere, taken up by marine organisms, and then “exported” to the deep sea when those organisms sink to the ocean floor after death.
