Cryoconite: organic matter content and genesis from Nigardsbreen, Norway

Abstract

Global temperatures have risen because of anthropogenic emissions, making glaciers retreat. Several factors affect glaciers and how they respond to climate change, one of them is cryoconite. Cryoconite is a dark fine-grained material made up of inorganic and organic material. Because of its dark colour, cryoconite has a different albedo than the glacier and absorbs more heat energy that makes cryoconite holes in the glacier. In this study cryoconite from the Norwegian glacier Nigardsbreen was analysed. The aim was to describe the organic material in the cryoconite and see where it came from using IR spectrometry, NMR, IRMS and LOI analyses. The result showed that the organic material points to an autochthonous carbon production from microbes in the cryoconite, but also a mixed origin such as transported plant material. The C and 13C values in the cryoconite samples show more decomposition values up-glacierand suggest that the samples get younger in age downhill. Inorganic material was mostly clay material (kaolinite and/or illite) and quartz. The exact source of the cryoconite inorganic material cannot be determined but results point to aeolian transport. The difference in the cryoconite organic material on the glacier may be due to elevation, slope, water leaching and sun exposure.