Master Thesis
Distribution of trace elements along a chronosequence at Damma glacier, Switzerland
Jens Hamberger (04/2022-10/2022)
Support: Britta Planer-Friedrich
The Damma glacier soil chronosequence already proved to be a suitable study site for understanding early pedogenesis and underwent many interdisciplinary studies. However, trace elements and the importance of their atmospheric deposition as primary source for young soils was neglected. Now, the present study focused on atmospheric deposition as potential source for trace elements in soils and the question of how suitable Damma glacier forefield is for this venture. Therefore, soil pH and total organic carbon were measured in soil samples from 2007, 2017, and 2022, corresponding to soil age ranging from 1 – 151 years, and total element concentrations were determined by ICP-MS. Soil pH decreased along the forefield and from 2007 to 2017 because of ongoing soil acidification. On the contrary, total organic carbon content increased through all years and along the glacial forefield due to already established vegetation and organic matter accumulation with increasing age. Iron, Al, Mn, P, Sr, Co, Cr, and Ni are potentially released by granite weathering due the concentration changes along the forefield which were likely associated to “islands” of ongoing soil formation during the re-advancement of the glacier and enhanced weathering because of preserved fine-grained material. On the other hand, S, Pb, and Cd are likely deposited out of the atmosphere visible in the increasing concentrations along the forefield, the difference in bedrock and soil concentration and the higher concentrations in the topsoil samples. Copper, As, Mo, and Zn showed properties associated to weathering and atmospheric deposition. Soils from 5 – 60 years were suggested as suitable to estimate atmospheric deposition because of the absence of interfering processes whereas the rest of the soils of intermediate age were more influenced by weathering products, and old soils by already established vegetation.