UK Centre for Astrobiology


Meet the group

Principal Investigator: Sean McMahon, Reader in Astrobiology


I am a palaeobiologist and astrobiologist: a geoscientist interested in the co-evolution of life and planetary environments across very large spans of space and time. As a tenured Chancellor’s Fellow at the University of Edinburgh and co-director (with Charles Cockell and Rosa Santomartino) of the UK Centre for Astrobiology, I focus on the study of biosignatures in ancient materials relevant to the early Earth, Mars, and beyond. My work has been published in a wide range of journals and reported with varying degrees of accuracy by diverse TV, radio, online and printed media. I am a Fellow of the Royal Astronomical Society and of the Geological Society of London, a member of the Palaeontological Association and the Astrobiology Society of Britain, and an Associate Editor of the International Journal of Astrobiology, published by Cambridge University Press. I am also a STEM Ambassador.

Background: I studied for an MEarthSci (Earth Sciences) at St Edmund Hall, University of Oxford (2006–2010) and developed an interest in early life and astrobiology under the tutelage of the late Martin Brasier (and, briefly, Lynn Margulis). This interest led me to the University of Aberdeen for my STFC-funded doctoral research (2010–2014) on the habitability of subsurface environments on Earth and Mars (supervisors: John Parnell, Gail Ferguson, and Graeme Nicol). I also undertook a NASA Planetary Biology Internship in the laboratory of Rocco Mancinelli at NASA Ames Research Center in California. After my PhD, I joined Derek Briggs' lab at Yale University for postdoctoral research on fossilization processes (2014-2017) funded by the NASA Astrobiology Institute, before returning to Scotland as a Marie Skłodowska-Curie Fellow at Edinburgh's UK Centre for Astrobiology (2017-2019). Except for a brief visit to Durham University as a visiting fellow at the Institute for Advanced Study, I have remained in Edinburgh since 2019, first as a Chancellor's Fellow and then (from 2023) as a Reader in the School of Physics and Astronomy and the School of GeoSciences. I also hold a BA in Philosophy from Birkbeck College, University of London.


Postdoctoral scientists

Corentin Loron, Royal Society Newton International Fellow


Corentin Loron (BSc Lille 1, MSc Uppsala-Lille-1, PhD Liège) is investigating the oldest fossil fungi and their pathways of fossilization.

Pamela Knoll, Human Frontiers Science Programme Postdoctoral Fellow

Pam Knoll

Pam Knoll (BS, PhD Florida State) is a physical chemist investigating biomineral selection by extremophile microorganisms.

PhD students

Edwin Rodriguez Dzul

Edwin (BSc Autonomous University of Yucatan, MScR University of Edinburgh) is researching the application of experimental taphonomy to microbial eukaryotes. He previously completed an MScR project in the group focused on the morphological and molecular preservation of fossil microbes in the ~407-million-year-old Rhynie Chert, Scotland.


Master's students

Mia Frothingham (MScR Palaeontology and Geobiology)


Mia (BA Harvard) is investigating the astrobiology of simulated exoplanet reflectance spectra. By merging the two seemingly distant fields of exoplanetary astronomy and laboratory microbiology, this research will provide a unique perspective of life on exoplanets and contribute to developing next-generation space-based instruments.

Susie Seddon-Cowell (MScR Palaeontology and Geobiology)


Susie (BSc University of York) is investigating the fossilization of bacteria under extreme conditions.


External members

Sigrid Huld (PhD candidate, Uppsala University)


Lead supervisor: Anna Neubeck

Sigrid (BSc Pavia, MSc Uppsala) is researching the biogeochemistry of manganese and the production of self-organized pseudofossils on early Earth and Mars.

Phil Vixseboxse (PhD candidate, University of Cambridge)

Lead supervisor: Alex Liu

Phil is an experimental palaeobiologist interested in the preservation of Ediacaran soft-bodied macrofossils.


Cat Gillen (PhD candidate, Durham University)


Lead supervisor: Peter Vickers

Cat Gillen (BSc Durham, MA LMU) is a philosopher of science working on biosignature uncertainty in astrobiology.



Melanie Podbielski (MScR Palaeontology and Geobiology, 2022)


Melanie (BS Appalachian State University) investigated the fossilization of iron-oxidizing bacteria and compared them with iron-mineralized pseudofossils produced in the laboratory.

She then moved to NASA's Space Life Sciences Lab at the Kennedy Space Center for further research in space biology. Her project there investigated how microgravity impacts the immune response of plants in preparation for a flight experiment onboard the International Space Station. This work was part of a collaboration between NASA and the University of Florida.

In 2023 Melanie returned to Edinburgh to begin a PhD investigating the potential of sulfate reducing bacteria for the production of metal nanoparticles (Ni and potentially Pd and Pt nanoparticles too). This process could be used to remove contamination from lithium ion battery leachates and make battery recycling more sustainable, and may have applications for in situ resource utilization and biomining in space.

Elisha de Mello (Physics MPhys project student, 2019)

Elisha completed an MPhys research project entitled, "Hydrodynamic Forcing of Stromatolite Morphology" based on numerical modeling of the growth of organosedimentary structures. Elisha is now a PhD student at the University of Sheffield.

Sam Johnson (Theoretical Physics BSc project student, 2020)


Sam completed a Senior Honours Project entitled, "Numerical approaches to self-organization in agates" based on the numerical modeling of diffusive and layered growth structures in agates. Sam then moved to Gonville and Caius College, Cambridge to complete the MASt in Applied Mathematics (Part III of the Mathematical Tripos), before beginning doctoral work at the University of Oxford.


 Lab mascot



Violet is researching the possible existence of squirrels in that tree. She is not allowed in the laboratories.