It looks like the set from a 1950s sci-fi flick, but this toxic, funhouse-coloured hot spring isn't humanity's first deadly encounter with alien biology. Although it is home to some very strange life forms, and we're not sure what would happen if those gloves came off. The Danakil Depression, a hydrothermal system stretching from Dallol Volcano to Lake Assal in Ethiopia, is one of the weirdest and most inhospitable environments on Earth. Rain and seawater, heated by underground magma, bubble to the surface at near-boiling temperatures. It's laced with an elixir of salts that form lumpy terrain reminiscent of a coral reef steeped in radioactive waste. Chlorine and sulphur-rich vapours produce an acrid fog that smells like farts and can sear the lining off human lungs.
It is a truly alien place — which is why it's so odd that the Danakil Depression has escaped scientific study until now.
For the first time, a field expedition led by Felipe Gómez Gómez of Madrid's Center for Astrobiology this month set out to investigate the region's geology, mineralogy and biology. From April 5 through to 7, the team measured pH, temperature, humidity and oxygen across the region's hot springs, all the while collecting samples of bacteria and testing new techniques for extracting their DNA.
"We are genuinely exploring new ground from a scientific point of view," Gómez said in a statement, adding that places like the Danakil Depression are of great interest to astrobiologists, who seek to understand how life could survive in even more extreme habitats off-Earth.
Indeed, studies of Yellowstone's famous rainbow hot spring, Antarctica's subterranean lakes and the Atacama desert's desiccating dunes, have already yielded important insights into how bacteria cope with blistering heat, extreme cold, too much salt and way too much radiation — and these insights are helping us imagine what sorts of life forms could thrive on Mars. The analyses from the first Danakil Depression expedition aren't complete yet, but we can be sure whatever the scientists find will help round out our picture of alien biology.
Meanwhile, if you've ever wondered what it's like to stumble around Mordor on acid, here are some photos from the expedition.
Weird, mushroom like concretions discovered at the Danakil Depression. Image: Felipe Gomez/Europlanet 2020 RI
A portion of the hydrothermal system at the Danakil Depression. Copper salts colour the water green. Image: Felipe Gomez/Europlanet 2020 RI
"Chimneys" produced by iron and sulphur deposits. Image: Felipe Gomez/Europlanet 2020 RI
A sulphur and chlorine fog hangs over the air at the Danakil Depression. Image: Felipe Gomez/Europlanet 2020 RI
Hydrothermal lake at the Danakil Depression featuring sulfates (yellow) and iron oxide deposits (red). Image: Felipe Gomez/Europlanet 2020 RI
Top: The Danakil Depression. Image: Felipe Gomez/Europlanet 2020 RI