A study from researchers at Cornell University and Spain’s Centro de Astrobiología using simulations involving clays and amino acids has given us pessimistic results. The study found that acidic fluids, like those that once flowed on Mars’ surface, may have destroyed evidence for life hidden within the iron-rich clays of the red planet.
Here’s what we are hoping: the clays on Mars, like on Earth, are organized into layers. Within those layers, again like on Earth, is where the evidence of biological life can become trapped and well preserved. These markers can include lipids and proteins and such. I’m not a biologist or a paleontologist, so I won’t mess up the details.
The issue is that acidic fluids can destroy this biological evidence. The researchers tried to preserve an amino acid called glycine within a clay. The clay had already been exposed to those acidic fluids. They then exposed the clay, with its preserved glycine, to ultraviolet radiation similar to that of Mars, and found gel-like silica afterward. Co-author Alberto G. Fairén summarized, “When clays are exposed to acidic fluids, the layers collapse and the organic matter can’t be preserved. They are destroyed. Our results in this paper explain why searching for organic compounds on Mars is so sorely difficult.”
“Constraining the Preservation of Organic Compounds in Mars Analog Nontronites After Exposure to Acid and Alkaline Fluids,” Carolina Gil-Lozano (Centro de Astrobiología, Madrid, and Universidad de Vigo, Spain) et al., 2020 Sep. 15, Scientific Reports