Le crioconiti: sostanza organica e nutrienti dalla superficie del ghiacciaio al suolo = Cryoconites: organic matter and nutrients from the glacier surface to the soil

Ice melting on the glacier surfaces leads to a concentration of all impurities included in the ice mass, originated from wind transport, microbial processes and accumulated in the snow. The concentration happens mostly in cavities on the ice surface and near its front, and the resulting dark and fine material is called “cryoconite”. It is particularly rich in organic matter, as shown by the dark colour, in nutrients and, sometimes, in anthropogenic contaminants. Glacier retreat caused by climate change is causing large quantities of cryoconitic materials to accumulate on the freshly released moraines, where, in protected sites, it can enrich the initial soil in necessary organic matter and nutrients for the encroachment of pioneer species. Cryoturbation (internal movements in the soil mass caused by freeze-thaw action) helps the integration of these materials within the soil mass, making it more stable. These processes are particularly well expressed close to the fronts of the Lauson and Lavassey glaciers.