The new study suggests focusing on the use of time-resolved analogs, which are dynamic analogous terrestrial environments where changes can be analyzed over many years.
The study was led by Professor Alberto J. Feiren, a scientist in the Department of Astronomy at the College of Arts and Sciences. It was co-authored by José L. Sanz of the Autonomous University of Madrid (UAM).
Scientists have been studying the extremely salty Tires Lagoon in central Spain. For two decades, the lagoon experienced alternating dry and wet periods before reaching full dry-out in 2015.
The key findings of the researchers: if life existed on Mars when there was liquid water on the surface of the planet, its drying up would not necessarily mean that life disappeared forever.
In addition, lipids – such as fatty acids or their derivatives – are more resistant to decay and should be preferred targets when looking for life in an arid world.
Feiren began studying Mars analogs during his Ph.D. at UAM.
“At that time,” Feiren said, “my co-author’s team was already interested in Tires, mainly as an analogue of Jupiter’s moon Europa, because of the high salt concentration in the waters of Tires.”
Now scientists have turned their attention to Mars, especially to the places where there were bodies of water before drying up during the Noachian (about 4 billion years ago) and Hesperian (3.7-3 billion years ago) periods.
The research team closely followed the gradual drying of Tires over the course of 25 years, using it to study the evolution of microbial communities in small, dry lagoons.
Samples from Tires were collected and analyzed in 2002, in the early stages of drying up, and again in 2021 when the lagoon completely dried up.
“We conclude that any possible early ecosystems on Mars likely collapsed when liquid water disappeared,” Feiren said, “but environmental change would have caused global ecological succession when hypothetical microorganisms evolved strategies similar to those currently being used. micro-organisms living in Tires, adapting to thrive in the very low water activity of the desiccated sediments.”
The group will continue to monitor Tires as any changes in water content will be of great interest.
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