Viruses are ubiquitous and found in seawater, atmosphere, and soil. An estimated 10 nonillion (10 to the 31st power) individual viruses exist on our planet—enough to assign one to every star in the universe 100 million times over. Generally not considered as living entities, viruses can only replicate with the help of a living host, and they are capable of hijacking organisms from every branch of the tree of life. Over the course of her third COOP placement and the realization of her honors project, Audrée Lemieux developed a new metagenomics approach to evaluate the diversity of viruses found in the sediments of the largest arctic freshwater body, Lake Hazen.
Audrée first used DNA and RNA extracted from soil and silt samples from Lake Hazen, which allowed her to identify the presence of viruses as well as potential animal, plant and fungal hosts. With increased Arctic glacier melts induced by rising temperatures, there is a risk for these previously trapped viruses to infect new hosts. This is called viral ‘spillover’, which is when a virus infects a new host for the first time.
Audrée subsequently applied an algorithm developed by Professor Stéphane Aris-Brosou’s group to determine the risk of viral spillover. Her results suggest that this risk was greater for lake samples taken closer to the point where larger waterways, which contain more meltwater from glaciers, flow into Lake Hazen, linking a consequence of climate change to viral spillover.
This project received significant media attention, which gave Audrée the opportunity to hone her skills in speaking to journalists. In an interview given to the English magazine NewScientist, she explained that for the moment, the risk of viral spillover into animal hosts leading to infectious disease spreading is minimal because there are fewer ‘bridge vectors’ like mosquitoes in the Arctic. However, animal species are likely to increase their range limits and migrate towards the poles due to climate change, which could eventually lead to these areas of the globe becoming a prime site for such spillover.
Over the course of this project, Audrée also gained several new skills in bioinformatics and learned to use tools such as R, Unix, Trinity, SPAdes and high-performance computing. With further work on bacteriophages already planned for the next year, Audrée already submitted her findings to a peer-reviewed journal. Audrée encourages undergraduate students to explore their options with COOP programs. There is great value in being proactive, seeking out projects you are interested in, and communicating with the professors leading these projects.