A new study published this week in Nature-Astronomy shows that if life had existed on Mars billions of years ago, Mars could be the host of underground microorganisms that produce methane as a by-product, known as methane-producing microorganisms. Scientists say that because meth

A new study published this week in Nature-Astronomy shows that if life had existed on Mars billions of years ago, Mars could be the host of underground microorganisms that produce methane as a by-product, known as methane-producing microorganisms.

Scientists say that because methane is the driver of climate change, these microorganisms may have irreversibly destroyed the Martian atmosphere, killing themselves in the process.

Today, this red planet is a cold and barren desert, but extensive observations and exploration have long revealed that the planet once had rivers, lakes, and perhaps even oceans, and therefore was once inhabited.

According to this study, the rich hydrogen in the Martian atmosphere may have maintained the existence of methane-producing organisms 4 billion years ago, and that is when the Martian climate is most suitable for life to survive. There, the study’s senior author, Regis Ferrière, professor of evolutionary biology at the University of Arizona, and his team applied several models to predict temperatures on the surface and crust, and how hypothetical ecosystems survived in it. "Our goal is to create a Martian crust model with a mix of rock and salt water, allowing the atmosphere to spread to the ground and see if methanogens can survive there," Ferrière said in a press release. "The answer is, generally speaking, yes, these microorganisms may survive in the Earth's crust," he added.

Ferrière said that because the surface of Mars is too cold, microorganisms are most suitable for survival “a few hundred meters above” of Mars’ crust. "Based on our findings, Mars' atmosphere may have been rapidly completely changed by biological activities over tens of thousands or hundreds of thousands of years," said Boris Schotry, the first author of the study and a postdoctoral fellow at the University of Paris, in a press release. "By removing hydrogen from the atmosphere, microorganisms will significantly reduce the climate of the Earth."

This is an attractive theory that illustrates how much we still need to know about Martian history, but our exploration of ancient life is far from over.