Never-before-seen lagoons created by recent freak storms in Chile’s Atacama Desert have killed a majority of its soils’ microbial life. This photo was taken after rains in 2017. All images courtesy of Armando Azua-Bustos.

When rain in the desert brings death instead of life

A mass extinction of bacteria in the Atacama Desert after unusual rains has surprising implications for the possibility of life on Mars.

Here’s a paradox to ponder: Rain falling on a permanently arid landscape refreshes and encourages life, right? Not always. Until three years ago, the hyperarid core of Chile’s Atacama desert — the location of the driest point on Earth and an important analog for Mars research — had not seen substantial rainfalls in 500 years.

Now sudden precipitation thought to be caused by global climate change has done unexpected damage to the microbes that live in this rare ecosystem, which are uniquely adapted to the hyperarid environment. What does this mean, and why is it important? We asked TED Fellow and astrobiologist Armando Azua-Bustos of the Centre for Astrobiology in Madrid, Spain, to fill us in on his findings.

First, fill us in about the characteristics of the Atacama, and why it’s associated with Mars?

The Atacama Desert, located in northern Chile, is the driest and oldest desert on Earth. It has been an arid place for the last 150 million years, and an extremely dry place for the last 15 million years.