A team of scientists studying the biodiversity of microscopic organisms living at the base of a slowly retreating glacier on the southern coast of Antarctica has made an intriguing discovery: separate life forms are working in collaboration to survive and thrive in one of the planet’s most extreme environments.
The researchers believe their findings could force a significant recalculation of previous Antarctic soil biodiversity estimates and provide unique insights into the mechanisms seemingly incompatible life forms employ to create and support a viable local habitat collectively.
“Here we reveal unexpectedly abundant and diverse microbial community even in these driest, coldest, and nutrient-poorest of soils, which suggest that biodiversity estimates in Antarctic soils may be greatly underestimated,” said corresponding author, Dr Dirk Wagner, a professor at the GFZ Helmholtz Centre for Geosciences and the University of Potsdam in Germany. “Furthermore, it provides important initial insights into the range of interactions between bacteria and eukaryotes in these harsh environments.”
Discovery IN Antarctica Adds to the Continent’s “Life” Story
Antarctica was once considered a frozen and (mostly) lifeless desert that barely supported the scant few organisms capable of braving its intense cold and limited sunlight. More recently, scientists working in Antarctica have made several discoveries rewriting the story of life on the planet’s southernmost continent.
While several study efforts are investigating Antarctica’s non-biological mysteries, including the disappearance of unusual formations on the continent’s surface and a Soviet-era underwater mystery dating back millions of years, understanding how disparate life forms endure this environment is critical to understanding our planet’s history and informs the search for life in the cosmos.
In 2021, scientists discovered “extremophiles” living beneath the Antarctic Ice Shelf. New Zealand scientists made a similar discovery when they found an entire community of organisms living and thriving beneath the Antarctic ice. Earlier this year, scientists found an equally diverse ecosystem of organisms living beneath the 14 meters of ice covering Antarctica’s Lake Enigma. In March, an iceberg the size of Chicago suddenly broke off, revealing a thriving community of organisms living underneath.
Hoping to build on those efforts by improving estimates of biodiversity in one of the harshest places on the continent, the place where a glacier has disturbed the soil, some members of the research team hitched a ride aboard the ‘ANT-XXIII/9’ expedition of the German research vessel ‘Polarstern’ to Antarctica.
After taking a helicopter to the front of a slowly retreating glacier in the Larsemann Hills on the southern shore of Prydz Bay, the research team began collecting soil samples. Based on their findings published in Frontiers in Microbiology, the trip wasn’t wasted.
Samples Reveal Unexpected Species Diversity
According to a statement announcing the discovery, the team collected samples at five distances from the glacier, ranging between zero and 80 meters. Three distinct samples were collected at each distance, ranging between zero and 30 centimeters.
Using a process called ‘high-throughput DNA barcoding,’ the team measured each sample’s bacterial and eukaryotic biodiversity. The study authors say evaluating this type of DNA is critical to distinguishing whether the samples contain dead or living organisms, particularly when examining species diversity.
“By distinguishing between intracellular iDNA from living organisms and extracellular eDNA from dead organisms, we could reveal colonizers and locally extinct species preserved in soils,” said Wagner. “This allowed us to understand the relationships between prokaryotic and eukaryotic microorganisms and gain insights into their interactions over time.
After counting all the identifiable organisms, the team’s haul netted 2,829 genetically defined species. As expected, the diversity of iDNA was most concentrated in the top layer, with a bacterial “species richness” 10.3 times greater than eukaryotes. The researchers also noted that each distance from the glacier had its own “unique range of species.” Notably, 40% of the identified species were found using eDNA, meaning they were dead.
Teamwork Makes the (Microscopic) Dream Work
A closer examination of the different life forms living at the base of this Antarctic glacier found several indications that these disparate species were working together to survive. For example, ‘cryophilic’ (cold-loving) fungi found closer to the glacier, where the soil is most disturbed, may contribute to the first phase of soil formation. Soil formation is critical for building habitats that other microscopic organisms occupy in these microenvironments.
“We detected previously unrecognized associations between bacteria and eukaryotes, for example between certain green algae and bacteria, which may promote nutrient exchange,” Wagner explained. “We also found consistent co-occurrence of certain fungi and actinobacteria, which suggests that these fungi could provide carbon for the bacteria by degrading organic matter.”
Taken as a whole, the team’s discovery offers previously unavailable insights into the overall species diversity living in a part of the world once considered mostly uninhabitable. Wagner also believes their findings suggest “novel mutualisms” between a “tightly linked consortia of species that optimize the utilization of resources,” which enable them to survive collectively in an environment they may not survive in individually.
“By focusing on both current and past lineages of microbes, our study shows how colonization and environmental alteration through ecological succession helped change the extreme habitat of Antarctica’s Larsemann Hills, making them gradually more hospitable to the current considerable diversity of life,” he concluded.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.