According to researchers, volcanic gases could have created an atmosphere almost devoid of oxygen. And while oxygen is believed to be one of key factors that enable life in general, this low-oxygen environment could have been perfect for the emergence of life.
"Reducing anoxic conditions are potentially conducive to the synthesis of prebiotic organic compounds, such as amino acids, and are therefore relevant to the possibility of life on Mars," the paper reads.
The paper points to another study, performed by Stanley Miller and Harold Urey in 1950, that showed that electrical pulses in an low-oxygen environment in presence of liquid water produced complex organic molecules. Oxygen in that environment would have oxidized the newborn organics, therefore inhibiting the creation of life.
"This is important from an astrobiology standpoint because these reducing anoxic conditions have been hypothesized as being important to the origin of life on the early Earth," said lead author Stephen Sholes, a Ph.D. candidate in earth and space sciences and astrobiology at the University of Washington.
"Yes, you need liquid water, but you also need appropriate conditions for life, and here we are finding that the volcanoes should have changed the atmosphere enough to be more conducive to forming complex bio-important molecules," he said.
There are two missions currently underway to investigate Mars at the moment — NASA's MAVEN (Mars Atmosphere and Volatile Evolution), which primarily examines atmospheric loss, and the European Space Agency's TGO (Trace Gas Orbiter), which looks at minority molecules in the Martian atmosphere.
However, a different mission that will probe the martian soil is needed, the scientists say, since anoxic conditions cause changes in soil that are detectable even billions of years later.
In the end, the team aims to create a model that will allow them to "learn how big of an eruption would be required to switch the atmosphere anoxic, and how long that atmosphere would last before it would switch back," Sholes said.