Combining molecular modeling and experiments to build an understanding of weathering of minerals on ancient Earth and extraterrestrial environments, and its effect on the evolution of carbon-cycles and habitability of planets.
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Earth’s atmosphere, water and biological activity can lead to weathering of rocks, creating new minerals and releasing nutrients into the environment. This process has been changing through the history of Earth, playing a role in compositions of soils, affecting the current biosphere and likely creating conditions for the origin of life and its evolution. Weathering is not unique to Earth and also occurs on other planets.
Molecular modelling is a powerful tool, allowing us to travel back in time and space and gain atomistic-resolution insights into the effects of ancient conditions or processes involving unattainable or rare extra-terrestrial minerals. Through modeling we can test hypotheses, explain and guide experiments.
In this project, we aim to understand the behaviour of clay minerals present on Earth and Mars under various, often extreme, environmental conditions. To this end, we will use molecular modeling to study ion exchange between range of clays under a variety of temperatures, pressures, salinities and acidities. Computational studies will be coupled with laboratory weathering experiments. Together, the results will be used to inform and predict the effects on the habitability for life and evolution of carbon-cycles.
The project is extremely timely with current space missions, aimed at getting insights into history of our planet and highlighting possibilities of the existence of life beyond Earth. It 1) bridges the gap in understanding how minerals influence the physical and biological environments, 2) promotes and develops molecular modeling of clays, as a non-destructive methodology for the study of sparse samples, and 3) brings the fundamental understanding of physicochemical weathering process at any/extreme conditions.
- What are the physicochemical factors driving ion release from clay minerals on Earth and Mars?
- How different environmental conditions, for example, extremes of temperature, pressure and acidity, affect ion exchanges?
- Would solutions formed from clays under these weathering conditions, favourable to life and what factors control habitability?
This project combines computational chemistry and laboratory work, allowing to cross validate results, feed information between the methodologies, rationalise observables, and guide experiments within the project.
Laboratory experiments will involve making solutions with given conditions and testing bacterial growth (habitability studies) in the Cockell lab. Solutions will involve selected clays and reconstructed solutions based on modelled ion exchange.
Molecular modeling will combine molecular dynamics (MD) and quantum mechanics calculations of ion exchange within the interlayer of the clay, mobility of the adsorbed ions, charge transfer between hydrated ions and structural clay ions, edge-site reformation under various conditions. The computational work will be carried out in Erastova group, using GROMACS engine for MD simulations and CASTEP for DFT on high-performance computers.
The project is interdisciplinary, combining molecular modeling, mineral sciences, microbiology and astrobiology. Through the duration of the project the student will be able to learn and apply numerous experimental and computational techniques. The student will also be able to acquire skills in software development and usage of high-performance computing resources. Overall, the student will develop a unique and highly desirable profile in these growing and influential research areas, make the graduate competitive on the job market at both industrial and academic level.
Example activities: Microbiology and geochemistry laboratory techniques; molecular modelling (such as CCP5 summer school and/or CECAM); high-performance computing and software development in Python/Bash (courses offered through ARCHER).
- A motivated student with interest in Astrobiology and Life at Extreme Conditions.
- Background in any of Chemistry, Physics, Biology or Geosciences subjects would be of great benefit to the project.
- Experience either in molecular modelling, or coding (Bash/Python), or usage of high-performance computing will allow a fast start on the project. Nevertheless, all the necessary training will be provided.
More information about research in the group, see http://www.erastova.xyz
For more details on the project, contact Dr Valentina Erastova valentina.erastova [ at ] ed.ac.uk
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