Researchers Just Found a Lichen Species That Can Live and Thrive on Mars. This Is Why It’s an Incredibly Fascinating Discovery

In the mid-2010s, a group of European researchers ascended to the highest, driest, and most inhospitable part of the Sierra de Gredos in Central Spain to collect lichens. Other scientists did the same in the Alps and in the McDurdo Dry Valleys in Antarctica. The intention was to send these lichens into space and observe what would happen to them.

The specimens spent 18 months on the exterior of the International Space Station (ISS). Notably, they survived the vacuum of space, lack of water, extreme temperatures, and radiation. This outcome was excellent news, but there was even better news to come.

An experiment on Earth. In addition to sending half of the samples to the ISS, the other half was preserved in a laboratory on Earth under conditions closely simulating the surface of Mars. This included temperature fluctuations ranging from -6.5 to 139 degrees Fahrenheit, exposure to cosmic-galactic radiation up to 190 megagrays, and a vacuum of between 10-7 to 10-4 pascals.

After the year-and-a-half experiment, comparisons between the samples revealed that those exposed to the Martian conditions exhibited twice as much metabolic activity as those in space. Notably, the Alps lichen (Xanthoria elegans) showed an 80% increase in metabolic activity. While this was intriguing, it was still not enough.

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Do these organisms merely survive, or do they thrive? A Polish research team recently made strides in uncovering this question. The goal was to study the physiological and biochemical responses of specific lichen species in real-time.

In the end, the 2010s study was unable to determine precisely what happened during those 18 months. It focused on examining the aftermath of the exposure, while Polish researchers paid particular attention to the processes involved.

Mixed results. One of the two lichen varieties the Polish team tested, called Cetraria aculeata, couldn’t withstand oxidative stress and associated damage. This was despite containing high levels of melatonin. However, another variety (Diploschistes muscorum) successfully activated its defense mechanisms, which included crystalline deposits.

Positive news. The study results provide intriguing insights into the challenges of survival and habitability on Mars. Additionally, they enhance scientists’ understanding of biological processes under simulated Martian conditions. The Polish study also illustrates how hydrated organisms respond to ionizing radiation.

Experts still don’t know if it’s wise to risk contaminating Mars with terrestrial life forms. However, it’s becoming increasingly apparent that this may be inevitable. In fact, it might already be happening with NASA’s Curiosity rover.

Images | Nicolas Lobos

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