Astrobiological studies of volcano-ice interactions on Earth and Mars
Dr Ian Crawford and Dr Claire Cousins
The science of astrobiology aims to understand the origin, evolution, and distribution of life in the Universe. One of the drivers of astrobiological research is the realisation that terrestrial life is able to thrive in environments that would once have been considered completely inimical to life, and that some of these ‘extreme’ environments are similar to those that have been identified on other planets, Mars in particular. The recognition of Mars as an important target for astrobiology has led to a number of recent and forthcoming missions to the planet, including the European Space Agency’s ExoMars mission. Although we do not yet know whether life exists, or has existed, on Mars, we can start to identify potentially habitable environments where future searches might be made.
An example of a terrestrial environment that is analogous to environments that could have existed on Mars occurs at the interface between active volcanism and overlying glacial ice. This interaction produces hot springs, hydrothermal pools, and hot mineral soils, which all have the potential to support well adapted and diverse microbial communities. Given the evidence for past volcanic activity on Mars, and the seemingly ubiquitous presence of crustal ice (especially at high latitudes), it seems unavoidable that volcano-ice interactions will have been a common feature of Mars’ geological history. The Leverhulme Trust has funded our project to explore the microbiology and biosignatures of terrestrial volcano-ice interaction environments, with a view to assessing the past or present habitability of similar localities on Mars.
Our research area is centred around the Kverkfjoll volcano in central Iceland, where we aim to conduct two expeditions during the project. Kverkfjoll is a partially subglacial volcano situated above the Icelandic hot spot. Here, hydrothermal fields near the summit consist of small, acidic (pH 2–3) meltwater pools, iron-rich springs, and subglacial drainage streams. The geomicrobiology of these environments has not previously been explored, and it provides an excellent focus for the research proposed here. We will also study the spectral properties of these environments, to assist in the detection of similar, past environments on Mars using remote-sensing observations. Last, but not least, we will subject samples collected from these environments to simulated Martian conditions in the laboratory, to determine whether the evolutionary adaptations that have enabled life to colonise these environments on Earth could allow for their survival on Mars.
Our ultimate aim is to explore volcano-ice interaction environments using a multi-disciplinary approach, the results of which will characterise these unusual habitats from a combined biological, geological, and planetary science perspective. In addition to extending our knowledge of the adaptability of life to extreme environments on Earth, our work will feed directly into the planning of future Mars exploration. In this respect, the timing of the present study is well suited to provide scientific input into the European Space Agency’s ExoMars rover and other future Mars missions.
