Spanish Lake proposed as ‘astronomical analogue of time’

The ongoing search for signs of life on Mars relies in part on terrestrial analogues – places on Earth that are very similar in geology and climate to the Red Planet in the past or present and that are easily explored.

A new study suggests focusing on another method: “time-resolved isotopes,” similarly dynamic Earth environments where changes over many years can be analyzed. Ferrin, a visiting scientist in the College of Arts and Sciences’ Department of Astronomy, led this inaugural study in his native Spain.

Ferrin is co-author of “Environmental succession during the draining of the supersaline Lake Therese (Spain) as an astronomical analogue of the time for the wet-to-dry transition on early Mars,” which was published February 8 in the journal Nature. Scientific reports. The other co-lead author is José L. Sanz of the Autonomous University of Madrid (UAM).

Their investigation took place in the hypersaline Lake Tirez in central Spain, which experienced alternating periods of dryness and wetness over two decades, before reaching complete desiccation in 2015.

Their main findings: If life existed on Mars when there was liquid water on the planet’s surface, drought wouldn’t necessarily mean that life disappeared forever. In addition, fat – like fatty acids or their derivatives – have a higher resistance to degradation and should be preferred targets in the search for life on a world without water.

Verín, who is a member of the Cornell Center for Astrophysics and Planetary Sciences and a research professor at the Center for Astrobiology (CAB) in Madrid, began studies on Martian isotopes while pursuing his Ph.D. in UAM.

“At the time, my advisors team was already interested in images of Tirez, mostly as an analogue of Jupiter’s moon Europa, because of the high concentration of salts in Tirez’s water,” said Ferrin.

They’ve since turned their attention to Mars, particularly sites that contained pools of water before they dried up during the Noachian (about 4 billion years ago) and Hesperian (3.7 to 3 billion years ago) periods. Ferrin’s research group—which included scientists from CAB and UAM—closely monitored the gradual desiccation of Tirez over a 25-year period, and used it as an opportunity to better understand the evolution of microbial communities in the small, dry lakes.

Sur samples were collected and analyzed in 2002, during the early stages of the drought, and again in 2021, when the lake has completely dried up.

“We conclude that any potential early ecosystems on Mars might have collapsed when the liquid water disappeared,” Viren said, but the changing environment would have set off a global ecological succession, with hypothetical microorganisms evolving strategies similar to those of the microorganisms now inhabiting Tire. , which are adapted to thrive in very low water activity in dried sediments.”

Viren said that the group will continue to monitor the city of Tyre, noting that any changes in its status regarding water content It will be of great importance.

“It would be particularly interesting if the ongoing dry decade in central Spain saw some mitigation and we could see at least a partial return of the water table,” he said. “This will allow us to expand our understanding of the astronomical symmetry of time for Mars, because the desiccation of Mars was a gradual process.”

Analysis of the response of microorganisms in pictures to presence liquid water Once again, after years of complete desiccation, it will provide new insights into understanding the evolution of potentially ancient ecosystems on Mars.”