The ice-free regions of Antarctica are regarded as the world’s coldest and driest deserts. Only few selected microbial species, including fungi, bacteria, archaea, and metazoans, are able to survive here. These organisms have to cope with a wide range of stressors, including frequent freeze-thaw cycles, a lack of nutrients and bioavailable water, intense solar radiation, and frequently high salinity, in order to survive. Despite these challenging environmental factors, cultivation-independent approaches have demonstrated in the last decades greater diversity within Antarctic deserts than previously predicted. These pristine ecosystems are good models for disentangling theories on the distribution ecology and evolutionary causes of microbial life because of their geographic isolation, severe physical settings, and relatively simple trophic relationships.
In this context, the research I am conducting in this environment focuses on two main objectives. First, I aim to describe the diversity of fungi and bacteria using advanced environmental DNA (eDNA) based methods. Secondly, through the same approach, I seek to understand the crucial factors that influence the emergence and differentiation of these unique and highly adapted life forms. To achieve these goals, we are expanding our investigations to encompass a wide range of localities throughout the entire Victoria Land region, ranging from coastal areas that are relatively more permissive to the most extreme inner localities. By encompassing such a diverse array of environments, we hope to gain comprehensive insights into the microbial life thriving in this region and uncover the key drivers of their adaptability and survival.
Figure 1: Landscape at Lake Joyce (Taylor Valley, Southern Victoria Land, Antarctica). Photo credit PNRA (Italian National Program for Antarctic Research).
Figure 2: Landscape at Battleship Promontory (Southern Victoria Land, Antarctica). Photo credit PNRA (Italian National Program for Antarctic Research).
The full extent of climate change impacts in this peculiar environment is not yet fully evident, but it is anticipated that these unique and highly adapted ecosystems may disappear. We conduct research that focuses on the relationship between soil microbial community richness and composition and the characteristics of their natural habitats to better understand and track potential changes in environmental conditions and their impact on communities. Additionally, we are currently conducting experiments to shed light on the influence of regional biological hotspots on the diversity of the most remote areas. This is particularly important because the origins of microbial propagules on the continent remain uncertain due to geographic isolation and limited wind dispersal from other continents. The expected increase in connectivity between strongly isolated habitats and their homogenization raises significant concerns. Another critical aspect that requires careful monitoring is the introduction of cosmopolitan and more competitive species. These species may be favoured by milder climate conditions, potentially outcompeting native taxa.
Figure 3: Landscape at Balham Valley (Southern Victoria Land, Antarctica). Photo credit PNRA (Italian National Program for Antarctic Research).