In just over a decade, samples of Martian soil taken by the Mars Perseverance rover are expected to return to Earth, after being recovered by the first humans to set foot on Mars.
While scientists are excited to see what the scientific findings await, they may need to temper their expectations.
That is the reason that the acidic fluids, – which once flowed across the surface of the Red Planet, – may have destroyed biological evidence hidden in the iron-rich clays of Mars.
A new article, written by researchers at Cornell University and Centro de Astrobiología in Spain, explains how they came to this conclusion.
Is there life on Mars?
In order to conclude that there was likely degradation of biological material on the red clay surface of Mars, the researchers performed simulations involving clay and amino acids.
Their discovery was published in, “Constraining Preservation of Organic Compounds in Analog Nonronites of Mars, After Exposure to Acidic and, Alkaline Fluids,” in Nature’s Scientific Reports.
We know that acidic fluids have flowed on the surface of Mars in the past, altering the clays and its ability to protect organic material said Alberto G. Fairén, the corresponding author of the article, explained in a press release.
Glycine, the ‘perfect informer’.
The researchers explain that the internal structure of clay is organized in layers, in which we would usually find well-preserved evidence of biological life, such as lipids, nucleic acids, peptides, and other biopolymers.
The team made simulated Martian surface conditions, by trying to preserve an amino acid called glycine, in a piece of clay that had previously been exposed to acidic fluids.
We used glycine because it could degrade quickly under the environmental conditions of the planet, said Fairén. It is a perfect informant to tell us what was going on in our experiences.
The difficulty to find organic compounds on Mars.
The researchers exposed the glycine-impregnated clay to ultraviolet radiation similar to that of Mars. The study finds out substantial photodegradation of the glycine molecules embedded in the clay.
Essentially, exposure to acidic fluids erased the interlayer space, turning it into gelatinous silica.
When clays are exposed to acidic fluids, the layers collapse, and organic matter cannot be preserved. Fairén said that the results in this article explain why the research for organic compounds on Mars is so difficult.
NASA’s Perseverance rover launched on July 30 and is expected to land at Jezero de Mars crater next February.
The rover will collect soil samples from the Red Planet, which will be collected and returned to Earth by the 2030s.
The results of the new study could prove to be a setback for our ability to detect the presence of all ancient life on Mars.