PermAVirThaw · Ancient viruses in thawing permafrost: who are they and how do they impact present-day ecosystems?

Around 17% of the Earth’s terrestrial surface is composed of permafrost, characterized by frozen ground for at least two consecutive years. Humanity has left Pandora's freezer door open⁠. With the poles warming 3-times faster than the rest of the world, permafrost is being rapidly lost, potentially releasing ancient microbes locked in frozen soil. Accumulated evidences show that microbes, including viruses, locked in ancient permafrost can stay viable over millennia. However, little is known about viruses that froze alongside many of these microbial communities, and their release due to permafrost thaw may directly affect the population dynamics of present-day hosts. To understand these impacts, we need to determine which viruses are archived in permafrost and which hosts they can infect. Viruses infecting plants and animals might pose major economic and human health threats whereas viruses infecting microbes can transform ecological systems on which we rely. Therefore, the Fellowship goals are i) to determine how the virosphere varies with permafrost age and type across the Arctic; ii) to quantify the capacity of virions extracted from permafrost to infect present-day microbes; and iii) to measure the impact of permafrost extracted virions on present-day microbial community diversity and carbon cycling. The main outcomes will be large-scale knowledge on the composition of the ancient permafrost virosphere and the influence of age (including palaeoenvironment) on virus persistence and diversity, as well as their capacity to infect present-day microbes and change biogeochemical cycles.