"It's a bit like seeing a penguin thrive in a tropical jungle." That's how Monash University scientist Dr Ry Holland describes new research that has shown Antarctic microbes can survive in temperatures ranging from -20°C to 75°C – a staggering 95°C temperature span.
The study, led by Monash University researchers from Securing Antarctica's Environmental Future (SAEF), shows that microbes' ability to live from gases in the atmosphere, including hydrogen and carbon monoxide, is likely active year-round across East Antarctica and forecast to increase with climate warming.
This process, known as aerotrophy, allows them to not only survive but thrive during Antarctica's dark, freezing winters, and also makes them suited to a future shaped by rising temperatures.
Dr Holland, who co-authored the study published in The ISME Journal, said the team's findings improve our understanding of how life survives in one of Earth's most extreme environments.
"In most surface ecosystems, photosynthesis is the key process that enables life to grow. However, it requires sunlight and water, two things that are in short supply during dark Antarctic winters, when water is locked up as ice," Dr Holland said.
"By contrast, the air is always there, providing a steady supply of hydrogen, carbon monoxide and other trace gases."
The team, including lead author Dr Tess Hutchinson, found that Antarctic microbes happily continue to consume these gases as an energy source at typical summer temperatures of 4°C and winter temperatures of -20°C, confirming that aerotrophy occurs year-round.
"When we continued to increase the temperature in the lab, we were surprised to find that they continued to consume hydrogen up to 75°C. This shows that while these microbes are adapted to the continent's cold conditions, they are not limited by them," Dr Hutchinson said.
To build a continent-wide understanding of the process of aerotrophy, the SAEF program partnered with national Antarctic programs and business partners to access sites across East Antarctica. Soil samples were collected in Dronning Maud Land with logistics support from White Desert, and from the Bunger Hills and Robinsons Ridge through the Australian Antarctic Program.
The team then measured how quickly microbes consumed atmospheric gases both in the lab and in the field. They also extracted and sequenced the microbes' DNA to identify which species were present, the genes they carry, and the energy sources they are capable of using. The findings show that aerotrophy is not an isolated adaptation, but a widespread and foundational survival strategy across Antarctica.
Dr Hutchinson says that this study is an important piece of the puzzle to understanding how resilient Antarctica's unique microbial ecosystems are to a changing climate.
"Aerotrophy is clearly a vital process supporting ecosystems across East Antarctica. It can occur in the dark or the light, in extreme cold and at surprisingly high temperatures. It's good to know that these microbes are resilient to rising temperature, but there are lots of other factors that also determine how microbes will respond to climate change that we are continuing to uncover."
About Securing Antarctica's Environmental Future (SAEF)
SAEF is an Australian Antarctic Program research and workforce development initiative. The program delivers world-class Antarctic and Southern Ocean science and policy advice essential for securing Antarctica's future, and will help secure ours.
