Led by Dr Dirk Wagner from the GFZ Helmholtz Centre for Geosciences and the University of Potsdam, the research uncovered thousands of bacterial and eukaryotic species in weathered soil debris in front of a retreating glacier in the Larsemann Hills. "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 Wagner.
The team gathered 26 soil samples at varying distances (up to 80 meters) and depths (up to 30 cm) from the glacier as part of the ANT-XXIII/9 expedition aboard the German vessel Polarstern. They used advanced DNA barcoding to assess the microbial diversity and distinguished between intracellular DNA (iDNA) from living organisms and extracellular DNA (eDNA) from the dead, revealing a broader picture of both current and historic biodiversity.
In total, researchers identified 2,829 distinct species, with bacteria outnumbering eukaryotes in species richness by a factor of over 10. They noted that each distance from the glacier hosted a distinct species composition, with surface layers showing the greatest iDNA diversity.
The study points to possible mutualistic relationships that may be key to microbial survival. For instance, cryophilic fungi near the glacier seem to initiate soil formation, enabling the colonization of other species. "We detected previously unrecognized associations between bacteria and eukaryotes, for example between certain green algae and bacteria, which may promote nutrient exchange," Wagner explained.
Using network analysis, the team found consistent co-occurrence patterns between microbial groups, including fungi and actinobacteria. "Our results indicate that microbial survival in extreme Antarctic habitats may be made possible by tightly linked consortia of species that optimize the utilization of resources," Wagner added.
The findings challenge current models of Antarctic biodiversity and hint at hidden mutualisms yet to be confirmed through experimental studies. "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," Wagner concluded.
Related Links
GFZ Helmholtz Centre for Geosciences
Beyond the Ice Age
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