Sterile Waters

where the life ends

Danakil Depression in Ethiopia is a depression (sunken landform) caused by the divergence of tectonic plates in the Horn of Africa – a peninsula in East Africa. Danakil is evidence of Africa and Asia moving apart. Considering the year-long average temperature, Danakil is the hottest place and is also one of the lowest places on the planet Earth. With all these geographical interests, Dallol: a hydrothermal system, tops the must-visit places of Danakil Depression.

Dicey Dallol

In the Danakil Depression, there is a cinder cone volcano named Dallol. With green acid ponds and salt lakes, the landscape of Dallol looks unprecedented. This unearthly land is uncertain too, says recent study published in Nature Ecology & Evolution by French-Spanish scientists team. 

According to this recent study, the yellow lakes rich in magnesium and hot, salty, hyperacid ponds of Dallol is sterile, means its devoid of life. These waters are not supporting life in spite of microbial dispersion due to wind and human interventions in this area.

The team used multiple techniques to before concluding this result, such as:

• microbial culture,
• fluorescent flow cytometry to identify individual cells,
• chemical analysis of brines,
• scanning electron microscopy combined with X-ray spectroscopy.

Though the waters of Dallol is sterile, the desert and canyon regions witness the presence of diverse halophilic archaea – salt-loving microorganisms.

Earlier this year, another study confirms that certain microorganisms can exist in this kind of extreme conditions. But with more samples and better-calibrated methods, this new study is denying the possibilities of life in the hyper acid and hypersaline waters of Dallol.

“In addition, our study presents evidence that there are places on the Earth’s surface, such as the Dallol pools, which are sterile even though they contain liquid water’

Purificación Lopez Garcia, Lead Scientist.

According to researchers, the abundance of magnesium and hyper saline and acidic conditions could be the factors preventing life. With this study, it is evident that the presence of liquid water alone does not confirm the possibilities of life, particularly in other planets.

Source:
Belilla, J., Moreira, D., Jardillier, L. et al. Hyperdiverse archaea near life limits at the polyextreme geothermal Dallol area. Nat Ecol Evol3, 1552–1561 (2019) doi:10.1038/s41559-019-1005-0

Written by M R Raghul