How extreme conditions on Mars could support life

Credit: Joseph Heili, Tanner Hoog, and Aaron Engelhart.

Many people might think that the search for life on Mars ended when NASA’s first rovers sent back images of the planet’s barren, harsh landscape.

However, scientists have continued to explore the possibility of life on Mars, inspired by the discovery that life on Earth can survive in extreme conditions.

This ongoing research broadens our understanding of what extraterrestrial life might look like and where it could exist.

Recent NASA missions have discovered large amounts of perchlorate salts on Mars. These salts can absorb water from the atmosphere, creating concentrated solutions known as brines.

Since liquid water is essential for life, NASA’s strategy in searching for life on Mars has been to “follow the water,” leading scientists to pay close attention to these perchlorate brines.

In a new study published in the journal Nature Communications, researchers from the College of Biological Sciences investigated how Mars’s unique geochemical environment could support life, either in the past or present.

The team, led by Assistant Professor Aaron Engelhart, tested two types of ribonucleic acids (RNAs) and protein enzymes from Earth to see how they functioned in perchlorate brines.

Their findings revealed that:

  • All the RNAs performed surprisingly well in perchlorate brines.
  • Protein enzymes did not work as well as RNAs in these brines. Only proteins from organisms that live in extreme environments on Earth, such as high temperatures or high salt, could function properly.
  • In perchlorate brines, RNA enzymes were capable of unusual reactions, such as generating new molecules with chlorine atoms—a reaction not previously observed by scientists.

“These results show that RNA is uniquely well-suited to the very salty environments found on Mars and could be present on other celestial bodies,” said Engelhart.

“This extreme salt tolerance could influence how life may have formed on Mars in the past or how it might be forming in the current conditions on Mars.”

The team is continuing to explore the chlorination chemistry they discovered, as well as other reactions that RNA can perform in high-salt environments. This research not only sheds light on the potential for life on Mars but also expands our understanding of the adaptability and resilience of life in extreme conditions.

By investigating how life might survive in the harsh environments on Mars, scientists are gaining valuable insights that could guide future missions in the search for extraterrestrial life. This ongoing research keeps the hope alive that we might one day discover life beyond Earth.