It might look like a drug-induced vision of hell, but for astrobiologists, the Danakil Depression in Ethiopia is heaven. With chlorine and sulfur vapor fogs hanging above its near-boiling, bubbling salty lakes, it is one of the least hospitable places in the world.
The Danakil Depression is found between the Dallol Volcano and Lake Assal, just off Ethiopia's border with Eritrea. Deeper than 100 meters (330 feet) below sea level, it’s one of the lowest places on Earth. Rainwater and seawater are heated by the area’s magma, creating a highly acidic 90°C (194°F) soup of sulfur, copper, and iron-rich salts. These salts create the deposits, coloring them with vibrant yellows, reds, and greens.
Considering this is such a unique place, it’s a surprise that scientists haven’t been swarming around it for years. However, a team of researchers from Madrid’s Centro de Astrobiologia ventured out to the geothermal plains on a three-day expedition earlier this month to look into the area’s geological curiosities and lifeforms.
"There are very few scientific publications on the site and no biological descriptions, so we are genuinely exploring new ground from a scientific point of view,” said Dr. Felipe Gómez Gómez, who led the expedition, in a statement.
Sulfates, iron oxides, and copper salts color the landscape. Felipe Gómez/Europlanet 2020 RI
For their expedition, the team was particularly interested in how life can survive in such an intense and harsh environment. Along with measuring parameters such as the pH level, temperature, humidity, and oxygen concentrations of the rocks and water, they also collected samples of the area’s extremophilic bacteria. By studying their DNA, they hope to learn how life can prosper in such extreme conditions, with a view to understanding how life might arise on other planets and moons.
Dr. Gómez said: “It is an amazing but hostile place – the temperatures were 42 degrees Celsius during the day and 30 degrees at night, and the chlorine vapor burned our airways. Any microorganisms living here will be extremophilic microbes of a major interest to astrobiologists.”
He added: “After mineral and geochemical characterisation, we will know what kind of materials and bacteria are present and be able to identify the most interesting sites for astrobiology purposes. We are now starting the analysis of our samples and are planning a follow-up trip in a few months time.”
"Hydrothermal system at the Danakil Depression. The yellow deposits are a variety of sulphates and the red areas are deposits of iron oxides. Copper salts colour the water green." Felipe Gómez/Europlanet 2020 RI
"Collecting samples from copper-rich pools of water between sulphate deposits." Felipe Gómez/Europlanet 2020 RI