Bringing Antarctica to the lab: a polar desert environmental chamber to study the response of Antarctic microbial communities to climate change

Polar deserts contain unique and sensitive communities responsive to climate-associated habitat changes. However, unlike temperate desert ecosystems, characterizing and predicting the responses of polar ecosystems to environmental change remains a significant challenge due to logistical constraints. Here we aim to demonstrate the use of a custom-designed Polar Desert Environmental Chamber (PDEC) to perform off-continent experimental ecological research. We did so by characterizing the structure and composition of arid edaphic bacterial communities collected from the McMurdo Dry Valleys during a simulated wetting event. The results were discussed in light of previous field observations. Rapid structural and compositional changes were observed during wetting and re-drying treatments. Those were driven by changes in the relative abundance of coexisting taxa, which fluctuated asynchronously over time in response to the treatments. While selection was the main ecological factor influencing communities during dry conditions or the initial wetting, with prolonged exposure to wetness, neutral processes began to drive community assembly. Ultimately, these observations reflect different adaptative responses from microbial taxa to water stress, which can be argued as beneficial to increasing resilience in polar deserts. Our findings demonstrate that experiments conducted in PDEC provide valuable contextual data on community response to environmental change and can accelerate our ability to assess biological thresholds to change within polar desert ecosystems. We advocate that, with careful consideration of key emulated environmental attributes, laboratory-based Antarctic research can complement fieldwork to achieve a nuanced and evidence-based understanding of the ecology of Antarctica’s ice-free regions.