Will the Antarctic tardigrade Acutuncus antarcticus be able to withstand environmental stresses due to global climate change?

Abstract

Since conditions in Continental Antarctica are highly selective and extremely hostile to life, its biota is depauperate, but well adapted to live in this region. Global climate change has the potential to impact Continental Antarctica organisms because of increasing temperatures and ultraviolet radiation. This research evaluates how ongoing climate changes will affect Antarctic species, and if Antarctic organisms will be able to adapt to the new environmental conditions. Tardigrades represent the main terrestrial components of Antarctic meiofauna; therefore the pan-Antarctic tardigrade Acutuncus antarcticus was used as model to predict the fate of Antarctic meiofauna threatened by climate changes. Acutuncus antarcticus individuals tolerate single event of desiccation, increased temperature, and UV radiation. Both hydrated and desiccated animals tolerate increases in UV radiation, even though the desiccated ones are more resistant. Nevertheless, survivorships of hydrated and desiccated animals are negatively affected by the combination of temperature and UV radiation, with the hydrated animals being more tolerant than desiccated ones. Finally, UV radiation has a negative impact on the life history traits of successive generations of A. antarcticus, causing an increase in egg reabsorption and teratological events. In the longrun, A. antarcticus could be at risk of population reductions or even extinction. Nevertheless, since the global climate changes will proceed gradually and an overlapping of temperature and UV increase could be limited in time, A. antarcticus, as well as many other Antarctic organisms, could have the potential to overcome global warming stresses, and/or time and capability to adapt to the new environmental conditions.