On Earth, some of the most hardy microbes use minerals as protection against ultraviolet radiation. Maybe Martian microbes used our strategy?
Life on Mars is hard anyway. The conditions can be so severe that scientists doubt whether microbes could survive. The atmosphere is thin, the surface is scorched by radiation, and the planet itself resembles a desert with winds and dust.
But perhaps there are places where life flourished in the distant past when there was a thick atmosphere and moisture on Mars. So, when scientist Janice Bishop looked at carbonate rocks in the Mojave Desert a few years ago, she immediately noticed a perspective for Mars.
Bishop in 2006 published an article in the “International Journal of Astrobiology,” calling iron oxide “ultraviolet sunscreen” for ancient photosynthesis on Earth. The results showed that the Mojave rocks also contained iron oxide coatings, under which carbonates were hidden.
“They all huddled under a red mineral at the top called hematite,” Bishop said. Hematite is also a common element on Mars. In addition, Senior Researcher and Chairman of the Astrobiology Group at the SETI Institute, Bishop is known for creating the CRISM (Compact Reconnaissance Imaging Spectrometer) tool for the Mars Reconnaissance Orbiter. The spacecraft did high-resolution imagery and also received spectroscopic inventions of Mars for more than ten years. This gave a whole mountain of useful information about the appearance of the surface.
Bishop is one of several scientists involved in the idea of “sunscreen”. For example, Gosen Ertem from the University of Maryland tracks how biomolecules can hide from ultraviolet radiation in various mixtures. She will present her results next month at the American Association for the Advancement of Science.
It is not clear yet how well Martian microbes (if they existed) lived in their environment. But iron oxide research, at least, brings valuable information about how our lives have evolved. In turn, this will help to better understand the mechanisms of development in other environments of the Solar System and on exoplanets.
The glandular formations (pictured is Karijini National Park in Western Australia) can occur in part from iron metabolized by microorganisms. Some are trying to figure out how microbes developed when there was no protective ozone layer on Earth, which is so much like today's Mars. In 2015, Tina Gauter from the University of Tübingen suggested that some strains of bacteria could create layers of iron oxide in their environment for protection.
The role of iron oxide microbes has also been studied by Kurt Conhauser from the Department of Earth and Atmospheric Sciences at the University of Alberta. He tracked the ancient iron cycle, studying how quickly microbes could generate iron oxide in various environments, as well as the role of protoplankton, which transports phosphorus on the seabed.
But is this process enough to save the Martian microbes today? Bishop believes that they existed in the distant past. “But what awaits us now?”.
However, she added that other researchers believe that life can be saved in the salt water of the planet, which accumulates in crankcases and other tilted places of Mars.