Microbes across the globe can survive on air alone: Study

The phenomenon was found to be restricted to Antarctica till 3 years ago

By DTE Staff
Published: Thursday 20 August 2020

Robinson Ridge in the Windmill Islands, east Antarctica. This is the site where UNSW researchers first discovered air-eating bacteria. Photo: Belinda Ferrari / UNSW

In 2017, Scientists from the University of New South Wales (UNSW), Australia, discovered that microbes in Antarctica could live on air — by feeding off the hydrogen, carbon dioxide and carbon monoxide to survive extreme conditions. The university researchers have now discovered that the phenomenon is global, and occurs in soils across the world’s three poles.

The findings essentially mean that microbes using trace gases (gases in the atmosphere other than nitrogen, oxygen and argon) as energy and carbon source to grow is not a process isolated to Antarctica.

In areas of low photosynthetic capacity, atmospheric chemosynthesis helps microorganisms grow.

Chemosynthesis is the process through which bacteria or other living organisms derive energy — from reactions involving inorganic chemicals — typically in the absence of sunlight.

The process is also called carbon fixation, through which inorganic carbon is converted to organic compounds by living organisms and stored as form of energy.

The researchers found that target genes responsible for atmospheric chemosynthesis were “abundantly and widely distributed in the polar soils of the Antarctic, Arctic and Tibetan Plateau in the Hindu Kush-Himalayas”.

After the 2017 study, the bigger question was to address whether chemosynthesis was naturally occurring in other parts of the world as well. So, the team did a global study — it collected the top 10-centimetre layer of soil from various sites at the three poles, which is the depth where most of the organisms the team studied were found.

The scientists analysed 122 soil samples from 14 terrestrial cold desert sites across Antarctica, the high Arctic and Tibetan Plateau. The samples were collected between 2005 and 2019.

They extracted Deoxyribonucleic acid from the soil samples and then sequenced it to detect the target genes responsible for the process of carbon fixation.

The team found that there were several ecosystems probably relying on microbial carbon fixation process, wherein microbes use the energy obtained from breathing in atmospheric hydrogen gas to turn carbon dioxide from the atmosphere into carbon so that they could grow.

“We found the genes involved in this process are abundant in cold deserts, although we are yet to study hot deserts, our finding probably indicates atmospheric chemosynthesis is contributing to the global carbon budget,” UNSW quoted Belinda Ferrari, senior author of the study, as saying.

She added:

Because these bacteria have adapted to survive and have the ability to use trace gases to live, their environment has selected them to become significant contributors to their ecosystems.

The research was published in the journal Frontiers recently. It was a collaboration between UNSW, the Australian Antarctic Division and China’s Institute of Tibetan Plateau Research.

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