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Studying the hottest place on Earth: Danakil depression in pictures

Published: 28th January, 2022 at 18:00
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Meet the microbiologists studying one of the most extreme environments on Earth.

In January 2019, a team of microbiologists at the French National Centre for Scientific Research (CNRS), led by Purificación López-García set out to explore environments that had never been studied before, in the deepest parts of the Danakil depression in Ethiopia. Hours in helicopters was required for the scientists to collect samples on isolated islands in the middle of soups of salt, at the bottom of inhospitable craters, or on the shores of multi-coloured mudflats.

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The Danakil depression is a salt desert at the crossroads of three tectonic plates on the East African rift. Intense volcanic and hydrothermal activity occurs there, and shapes the hottest place on the planet. The region is often viewed as similar to the planet Mars, therefore it is an ideal place to research the physical and chemical limits of life on Earth.

Satellite images had to be carefully analysed and many overflights were conducted before finding the right zones to study. A seasoned pilot hired by the team circled the Danakil region looking for the safest places to land, as a helicopter was the only safe way to gain access to the site.

Filled with excitement and curiosity, the team disembarked with a plethora of measuring instruments and sampling tools. They sunk into mud and in tepid hyper-salted water, as well as walking on chaotic and sharp flows under the harsh heat of the desert, 120 metres below sea level.

For two weeks, the photographer Olivier Grunewald and the journalist Bernadette Gilbertas were part of this expedition. The scientists uncovered interesting discoveries while they were still on site: they found stromatolites, microorganisms which are known for building very old rock deposits. It was the first time such formations had been reported in Danakil and their discovery may be the largest one to date.

These samples were then taken back to laboratories in order to study the traces of life hidden in the mysterious landscapes of the Danakil depression.

The Danakil delta

Aerial view of Danakil basin
Landscapes of the salt lakes of the Danakil plain. The largest lakes have names, Karum, Bakili, but many still unknown are not named. Some of these lakes, which are underwater for several years, may disappear or reappear according to the tectonic movements of the African Rift. Photo by Olivier Grunewald

The shores of Lake Bakili

Shores of Lake Bakili
Sample collection on the shores of Lake Bakili, east of the Gada Alé volcanic chain. These areas are totally inaccessible without a helicopter. Photo by Olivier Grunewald

Tricky landing sites

Looking for formations of stromatolites
Determining where the helicopter would land was the first step in obtaining authorisation from the local military services. This research was done from satellite images by looking for areas with anomalies, such as particular volcanic configurations or islands on the lakes. The team found formations of stromatolites, living organisms leaving mineral deposits, known in different parts of the world as the oldest forms of life that have left fossil traces. Photo by Olivier Grunewald

Heart of a volcano

heart of the Catherine volcano crater
Helicopter drop off and sample collection in the heart of the Catherine volcano crater in the Gada Alé volcanic chain. Photo by Olivier Grunewald

Investigating the crater

sampling in the heart of the Catherine volcano crater
Purificación López-García and David Moreira, both microbiologists, collect samples inside the heart of the Catherine volcano crater in the Gada Alé volcanic chain. Photo by Olivier Grunewald

Collecting stromatolites

collecting some stromatolites
Purification Lopez-Garcia is seen collecting some stromatolites, living organisms leaving mineral deposits, known in different parts of the world as the oldest forms of life that have left fossil traces. Photo by Olivier Grunewald

Volcano of Gada Alé

microbial samples on the shores of Lake Bakili
Collection of microbial samples on the shores of Lake Bakili east of the Gada Alé volcanic chain. The scientists had to work through the extreme heat of the Afar region of Ethiopia, in one of the lowest areas on the planet. Photo by Olivier Grunewald

The Yellow lake

Collection of samples in the first lakes of the Danakil depression
Collection of samples in the first lakes of the Danakil depression south of the Dallol site, Yellow lake and Black lake. It is the study of these first lakes in the salt plain that motivated this mission to explore the lakes near the volcanic chain of Gada Alé and Erta Alé. Photo by Olivier Grunewald

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The Black lake

Aerial view of the black lake
The 'Black lake' from above, south Dallol Geothermal site. Photo by Olivier Grunewald

Sampling the black water

Collecting samples from Yellow lake and Black lake
Collection of samples in the first lakes of the Danakil depression south of the Dallol site, known as Yellow lake and Black lake. Photo by Olivier Grunewald

Salt crystals

salt crystals and various micro-organism under microscope
Back at the CNRS laboratory at the Orsay-Paris Sud University, France, samples of salt crystals and various micro-organisms brought back from the Danakil salt lakes are imaged by a microscope of 400x magnification. Photo by Olivier Grunewald

Microscopic bacteria

salt crystals and various micro-organism under microscope
Cyanobacteria (unicellular microorganisms) are pictured under a microscope of 400x magnification, as imaged by the CNRS laboratory at the Orsay-Paris Sud University, France. Photo by Olivier Grunewald

Authors

James CutmorePicture Editor, BBC Science Focus

James Cutmore is the picture editor of BBC Science Focus Magazine, researching striking images for the magazine and on the website. He is also has a passion for taking his own photographs

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