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The Most Inhospitable Place on Earth May Still Support Life

If you’re looking for proof that life could exist even on planets with extremely hostile environments, a good place to start is in the Danakil Depression in Ethiopia – a place that many experts consider to be the most extreme and inhospitable place on Earth. Is it? Does it support life? For the first time, a research team has investigated the site and found not one, not two, but three different severe ecosystems and some surprising answers.

A multicolored hydrothermal system - the yellow is sulfates, the red is iron oxide and the green is copper salts

A multicolored hydrothermal system – the yellow is sulfates, the red is iron oxide and the green is copper salts

The Danakil Depression is part of the Afar Triangle on the Horn of Africa at the intersection of three tectonic plates – the Afro-Arabian Rift System comprised of the Nubian, Somalian, and Arabian plates. The depression, between the Dallol Volcano and Lake Assal, bottoms out at 100 meters (330 feet) below sea level, making it one of the lowest places on Earth. It’s also has the hottest average annual temperature on Earth, and that’s before you stand next to the water, which is near boiling and spewing chlorine and sulfur vapors.

Sulfur and chlorine vapors over a hot pool in the Danakil Depression

Sulfur and chlorine vapors over a hot pool in the Danakil Depression

This depression sounds depressing. Why would anyone – or anything – want to live in the Danakil Depression, let alone visit there?

Any microorganisms living here will be extremophilic microbes of a major interest to astrobiologists.

That’s why Dr Felipe Gómez Gómez of Madrid’s Centro de Astrobiologia (INTA-CAB) led an expedition there this past April for the Europlanet 2020 Research Infrastructure, a multi-national, multi-corporate group active in planetary research. What they found were multicolored, boiling pools that comprised three distinct ecosystems – the yellow contained sulfur, the yellowish-brown was sulfate minerals and the red was loaded with iron oxide.

 

One of the pools containing sulfate deposits.

One of the pools containing sulfate deposits.

In two of them, they also found thermal chimneys of extremely hot water where different types of thermophilic bacteria could live. They collected samples of bacteria and are analyzing them with a new technique for DNA extraction.

Gomez says these areas match places in the solar system where life could be found.

In the case of this iron-rich ecosystem, there are several places on Mars which are also very iron-rich. Going farther, in Jupiter’s Europa moon, we are expecting very clear sulfate-associated minerals.

Can life be found in the Danakil Depression? It already has – and not just any life. This is near where the 3.2 million-year-old Lucy Australopithecus fossil was discovered, earning it the nickname “the cradle of hominids.”

If the extreme primordial soup kitchen known as the Danakil Depression can support life that may have evolved into the first hominids, can the same recipe exist on other the inhospitable planets and moons? Gomez and his team are heading back there to help find out.