Viable metabolisms in a simulated martian environments

Microbes have multiple ways of producing energy. Which of these methods are possible depends on the chemistry of the environment the microbes are in (e.g. not enough of a metal or too much salt), with only specific methods working in certain environments. The same would be true of any waters that might continue to exist on Mars. To narrow down which methods of producing energy would be theoretically possible we simulated martian waters using a collection of minerals that are chemically similar to the chemistry measured by the Mars rover Curiosity in a crater on Mars. We added mud from an estuary to the simulated martian water and identified which microbes were able to grow. We then repeatedly transferred the growing microbes to fresh “martian” water to dilute out the nutrients from the mud. Over time we observed that most of the microbes from the mud have been lost but a few specific microbes were growing well. From this we hope to investigate changes in the chemistry of the water that happen because of these microbes, to try and identify specific chemistries that can be looked for by the future rover missions on Mars seeking evidence of life