The surfaces of glaciers and ice sheets host diverse and active microbial ecosystems wherever liquid water is present. Microbial activity in these supraglacial ecosystems is supported by photosynthetic carbon production, alongside carbon and nutrients derived from snow and ice melt, direct atmospheric deposition, and windblown debris from adjacent ecosystems (e.g. Telling et al., 2010; Annals of Glaciology, 51, 135-144.; Yallop et al. 2012; ISME Journal, 6, 2302-2313). While visible incoming solar radiation at ice surfaces is essential for supporting this photosynthetic life, coincident short wavelength ultraviolet radiation can be highly deleterious to microorganisms, by damaging biomolecules such as DNA (Cockell, 2000 Planetary and Space Science 48, 203-214). To combat this, microorganisms that inhabit glacier and ice sheet surfaces have evolved mechanisms to protect themselves from UV radiation. These include producing dark protective secondary pigments to shield themselves (Yallop et al., 2012) and the aggregation of individual microorganisms into complex microbial aggregates of inorganic and organic material (Hodson et al., 2010; Journal of Glaciology, 56, 349-362). Importantly, both of these mechanisms can result in the darkening of snow and ice surfaces, resulting in a reduction in albedo, and increased snow and ice melting – ‘bioalbedo’ effects with the potential for positive feedbacks on glacier and ice sheet melting during ongoing climate warming (e.g. Yallop et al., 2012; Ryan et al., 2018; Nature Communications 9, Article number 1065). This project will use a combination of laboratory experimentation (via a temperature controlled UV enhanced solar simulator, and UV/visible spectrometer), field experimentation and modeling to quantify the effects of differing fluxes of UV radiation on the ecology and bioalbedo of supraglacial ecosystems.
This project is part of the ONE Planet DTP. Find out more here: View Website