Astrobiology is a field that brings together the disciplines of Earth and planetary science, biology, chemistry, physics, and astronomy to explore for the presence of life beyond Earth.
Understanding the environmental controls and geochemical processes that make a habitat suitable to microorganisms on Earth is a crucial step to guiding astrobiological exploration of our solar system. At the EEGL, our research focuses on investigating how microorganisms can leverage mineralogy to make otherwise hostile, arid and toxic environments habitable. We are studying environments that, at first glance, seem hostile compared to classical “best case scenario” habitats (e.g., freshwater lakes). In these harsh settings, microorganisms can use mineral behaviour to scavenge water and nutrients, to regulate pH, and to fuel their metabolisms. Using mineral behaviour as a guide, our approach allows us to identify new materials that could preserve signs of extant or extinct life beyond Earth.
One of the most significant challenges in the field of astrobiology, especially in relation to the search for life on Mars, is the ambiguity in identifying putative biosignatures. We have been using stony meteorites as a naturally occurring geochemical standard that could be used for biomarker detection throughout our solar system. Stony meteorites are sterile when they fall to a planet’s surface and – given their narrow ranges in mineralogical, elemental and stable isotopic compositions – they interact with Earth’s biosphere in a consistent and unambiguous manner.
You can learn more about our work on first colonization of meteorites by environmental microorganisms under the harsh conditions of Australia’s Nullarbor Plain, and the biomarkers they produce, in three recently published studies: (1) Tait et al. (2017) Frontiers in Microbiology, (2) Tait et al. (2017) Geochimica et Cosmochimica Acta, (3) Tait et al. (2020) Astrobiology.