The microbiota playing "musical chairs" in a glacier retreat zone of maritime Antarctica

Most of the Antarctic continent and surrounding islands are permanently covered by ice. However, due to longterm natural and short term human-induced climate changes, glaciers in the maritime Antarctic islands are currently retreating, exposing new substrates for colonization by microorganisms and plants. Therefore, the aim of this study was to characterize the microbial communities along a transect comprised of soils with different exposition times since the glacier retreat in Barton Peninsula (King George Island). We observed an intense degree of microbial succession in young soils located in the Recently Exposed Area (REA), analogously to a game of 'musical chairs' where microbial species rapidly occupy available niches as new environments emerge. In contrast, more developed soils exhibited a less dynamic community turnover. The co-occurrence networks of both bacteria and fungi presented a less modular structure and a higher connectance in the REA, whereas a more modular structure was found in the three networks of the more developed soils. This suggests that these communities are more susceptible to external perturbations and microbial succession. Furthermore, the functional prediction demonstrated that the functional redundancy is lower in the REA than in more developed soils. The surprising high diversity of microbial communities adjacent to the glacier front deserves further studies to compare with different areas (in terms of substrate, climate) under a common present-day warming scenario.