PhD in Geographical and Earth Sciences - Viruses in fractured basalt aquifers: terrestrial analog for a potential Martian subsurface microbiome?

Start Date: 01 October 2025

Motivation: On Earth, viruses are the most abundant microorganism in seawater (Suttle 2007). The relative abundance of viruses in terrestrial groundwaters is not yet known, but recent studies point towards a large and highly novel subsurface virome (Wu et al. 2024). Given the widespread distribution of basalt in both the terrestrial and Martian geospheres (Hauber et al. 2011), and the hypothetical existence of a past or extant Martian subsurface biosphere strongly dependent on groundwater (e.g., Michalski et al. 2013), a study of terrestrial viruses and virus-like particles (VLPs), and their structural or biogeochemical biosignatures, from basalt aquifers would provide valuable analog data for potential future astrobiological investigations of the Martian subsurface. 

Aims and Methods: In this project, we will first study viral structural biosignatures in   groundwater samples collected from terrestrial basalt aquifers. We will perform this work with cryo-transmission electron microscopy, using both natural groundwater samples and samples “spiked” with bacteriophage cultures (viruses that only infect bacteria; i.e., non-pathogenic towards humans) in various states of structural degradation. We will also sequence viral genomic DNA from a suite of basalt-derived groundwaters to characterize the virome of basalts, and test for amplifiable artificially degraded viral DNA with next-generation sequencing technology. 

Research outputs: the results from this project will provide a baseline of information against which to investigate possible Martian virus-like structural and genomic biosignatures in future sample returns. The project will also inevitably make new discoveries about the abundance of viruses in terrestrial groundwaters, their potential to influence biogeochemical cycling, and their genome capacities. This interdisciplinary project will combine microbiology and earth science to create new knowledge in the field of astrobiology. 

References: 

Hauber, E., Brož, P., Jagert, F., Jodłowski, P. and Platz, T., 2011. Very recent and wide‐spread basaltic volcanism on Mars. Geophysical Research Letters, 38(10). 

Michalski, J.R., Cuadros, J., Niles, P.B., Parnell, J., Deanne Rogers, A. and Wright, S.P., 2013. Groundwater activity on Mars and implications for a deep biosphere. Nature Geoscience, 6(2), pp.133-138. 

Suttle, C.A., 2007. Marine viruses—major players in the global ecosystem. Nature reviews microbiology, 5(10), pp.801-812. 

Wu, Z., Liu, T., Chen, Q., Chen, T., Hu, J., Sun, L., Wang, B., Li, W. and Ni, J., 2024. Unveiling the unknown viral world in groundwater. Nature Communications, 15(1), p.6788. 

Eligibility:

The project is suitable for a UK or international graduate with a 2:1 honours degree or above (or international equivalent) in Geology or Earth Science, Chemistry, Microbiology or a related subject.  

The ideal candidate will have an interest in microbiology, virology, astrobiology, chemistry, evolution of life in the solar system. 

Applications should include a 2-page CV and 1-page cover letter (pdf format required for both), explaining why you are interested in this research project. Applications not submitted in this format will be rejected. Applications should be emailed to Leenah Khan (Leenah.Khan@glasgow.ac.uk) by 5pm on the 7th of March 2025, with the email subject ‘GES STFC PhD studentship 2025’. Late applications will not be considered.  

We expect to hold interviews the week beginning 24th March.