Antarctica's Complex Ice Caves Could Shelter Distinct Forms of Life

While Antarctica's surface seems lifeless and stark, its volcanic ice caves may host thriving ecosystems. Active volcanoes like Mount Erebus on Ross Island and others in Victoria Land release steam and gases, creating heated sanctuaries within ice formations and cave networks.

"The caves are encased in ice, yet some areas can reach temperatures as high as 20 degrees Celsius [68 degrees Fahrenheit], similar to a warm summer day," explains Ceridwen Fraser from Australian National University's Fenner School of Environment & Society in an email to Mytour. "While many caves remain dark due to thick ice, others with thinner ice allow light to seep through."

Fraser's team discovered DNA from various plant and animal species in these caves. While much of the DNA aligns with known species like moss, algae, and nematodes found elsewhere in Antarctica, the team also uncovered genetic traces of life forms potentially unique to these volcanic ice cave environments.

"Some DNA sequences didn't closely match any entries in online databases, suggesting the possibility of species uniquely adapted to these caves and found nowhere else," Fraser notes. "This hints at exciting discoveries about Antarctica's biodiversity."

Although the DNA from volcanic sites doesn't definitively confirm the presence of living plants and animals, it provides intriguing clues about potential life forms. The next phase of research will focus on obtaining direct evidence by finding the organisms themselves in samples.

Searching for Life in the Most Challenging Environments

Collecting samples from Antarctic volcanic sites is a daunting endeavor. Laurie Connell, a molecular and biomedical sciences researcher at the University of Maine and co-author of the study, describes the journey as physically demanding. After arriving on the continent, the team was transported by helicopter partway up Mount Erebus. They camped in tents for at least two nights to adjust to the altitude before hiking or snowmobiling to the ice caves.

At one point, Connell and her team endured a blizzard, spending four days confined to their tents as fierce winds and snow raged outside. The harsh conditions prevented them from leaving even for basic needs, relying on a bucket for sanitation and limited access to their food supplies.

"Since it was Thanksgiving, we decided to reserve our last packets of dry soup mix and crackers for the holiday," Connell recalls. "When we woke up on Thanksgiving morning to prepare our 'feast,' we discovered our hot water had cooled to lukewarm. It was quite disappointing."

After reaching the field station at Mount Erebus, where temperatures drop to minus 30 degrees Fahrenheit (minus 34 degrees Celsius) away from geothermal areas, the team dispersed to various locations. Using ropes and harnesses, they explored geothermal features such as heated soil patches, unstable ice domes called "ice hummocks" covering volcanic vents, and intricate ice towers and caves.

The unidentified DNA from the volcanic sites showed the closest resemblance to arthropods. This diverse group, characterized by exoskeletons and jointed limbs, includes over a million species, from lobsters and centipedes to microscopic copepods.

Arthropods have also been discovered in other parts of Antarctica, particularly in the 0.3 percent (or less) of the continent not covered by ice. In these areas, life must endure not only extreme cold but also severe dryness. Despite much of Antarctica being buried under ice up to 3 miles (5 kilometers) thick, its interior receives an average of just 2 inches (5 centimeters) of precipitation annually, mostly in the form of snow.

Despite the unforgiving conditions away from the coast, Antarctica harbors extensive ecosystems beneath its ice, which scientists are now beginning to investigate.

A Desert Abundant with Life

"Antarctica is often seen as barren, but life thrives in its most unexpected corners—on mountain rocks, within sea ice layers, and in dry 'deserts,'" Fraser explains. "Why wouldn't it also flourish in these warm, inviting caves carved by steam between ice and rock?"

In East Antarctica, Lake Vostok lies beneath 2.3 miles (3.7 kilometers) of ice, isolated from the atmosphere for roughly 15 million years. A 2013 study revealed genetic traces of 3,507 known species and approximately 10,000 unknown species in samples from the lake. Additionally, resilient bacteria have been found in briny liquid water networks discovered in Antarctica's McMurdo Dry Valleys, where iron-rich, blood-red waterfalls flow.

Scientists must carefully determine whether the DNA found in these extreme Antarctic locations belongs to organisms that genuinely inhabit the area or were introduced temporarily. "Microbes and spores could be carried by air, or contamination might occur through clothing, equipment, or other means," explains Bradley Tebo, a professor at Oregon Health and Science University who has participated in Mount Erebus sampling expeditions.

Connell notes that her team was aware of a British expedition that climbed Mount Erebus over a century ago, visiting many of the same sites they sampled. In 1912, six members of Robert Falcon Scott's team ascended the 12,448-foot (3,794-meter) volcano to gather geological samples and conduct surveys.

"We discovered remnants like ash tree fragments, likely from their equipment," Connell states. "This raises the question: which DNA traces are remnants of early expeditions, and which represent current life in Antarctica?"

The DNA findings at Mount Erebus may only scratch the surface of the diverse life within its volcanic ice caves. Antarctica boasts over 100 volcanoes, each potentially harboring its own network of ice caves and tunnels.

"We still don't know how many cave systems exist around Antarctica's volcanoes or how interconnected these subglacial environments are," said Charles Lee, a co-author of the study, in a statement. "Identifying, accessing, and exploring these areas remains a significant challenge."

While Antarctica is notoriously challenging to access and explore, even more extreme environments exist. Scientists believe that studying life and its subsurface habitats in Antarctica's harsh conditions could provide insights into the potential for life in similarly extreme locations, such as Mars.

"This study, along with others, shows that volcanic activity can support life in extreme environments," Fraser explains. "This raises the possibility of finding life around volcanoes on other planets or moons, even under harsh atmospheric conditions."