"The following work was performed using a variety of field, lab, analytical and numerical techniques:
1. The fossil record of Earth's subsurface ""deep biosphere"" was surveyed and reviewed, showing it to be extensive but poorly understood.
2. New samples were collected from sites of ancient subsurface fluid flow in Italy and the UK and analysed with a variety of methods for the presence of signatures of ancient subsurface life.
3. Quantitative reasoning was used to investigate the size of the ancient deep biosphere on Earth.
4. Abiotic processes capable of mimicking fossils of subsurface-dwelling microbes were discovered and investigated.
5. Implications for the search for ancient life on Mars were drawn out using Mars-analogue sample materials and mission-analogue analytical techniques.
6. Minerals formed by microbial activity in sediment were found in association with fossils of early soft-bodied animals, helping to explain their preservation.
At the end of the fellowship period, the work had resulted in 11 articles in scientific journals (of which 1 was in review and 1 was in press); further articles based on the work are anticipated.
Results were also disseminated at international conferences and meetings: the Scottish Planetary Science Research Network meeting 2017, the European Geosciences Union meeting 2018, the European Astrobiology Network Association meeting 2019, the Palaeontological Association meeting 2018, and seminars at the Universities of Leeds, Oxford, Cambridge, and Uppsala.
Non-academic audiences were engaged through 3 articles for popular magazines (of which 2 were for children), widespread media coverage of several papers, and public talks."
