POTENTIAL IMPACT OF THE ARCTIC GLACIER RECESSION ON OUR CLIMATE

The Arctic is warming three times faster than the rest of the world in part due to the phenomenon called Arctic amplification. The increase in de-glaciated land regions predictably leads to greater aerosol emissions and accelerates Arctic amplification by a reduced reflection of solar radiation, changing albedo. However, the role of aerosol-cloud interactions and cloud feedback is overlooked and not well understood in the Arctic. In particular, the role of clouds containing ice particles remains highly uncertain. To better understand the climate impact associated with aerosol particles emitted from de-glaciated soils, we characterized the immersion freezing efficiency of surface soil samples collected in 2019 from Southern Spitsbergen. A total of 8 samples were collected along a latitudinal transect from the top of the catchment of the Ariebreen glacier (ARB; approx. 500 m a.s.l.) to the sea shore (approx. 5 m a.s.l.), Hornsund area. Half of the samples were from the inner ARB (more recent; in the north), and another half was sampled in the outer ARB (older; in the south) de-glaciated spots. For our immersion freezing experiment, we used 0.1 wt% powder from each ARB sample, as well as heat-treated samples, to estimate the concentration of ice-nucleating particles (INPs) in a unit mass of each sample, nm (g-1), as a function of temperature (0 °C to -25 °C). Our immersion freezing results of the ARB samples indicate a gradual decrease in freezing efficiency (nm) from old/south ARB (highest) to new/north ARB (lowest). From the heat treatment analysis, we see the inclusion of heat-sensitive biogenic INPs in most samples. Besides the immersion freezing, the results of trace element analysis and ICP-MS data, full next- generation sequencing data describing microbial communities along the sequence, for the ARB samples will be presented. Knowing the type of microorganisms for de-glaciated areas, as well as those beneath glaciers, will enable us to relate the freezing results to the chemical and biological properties of the samples.