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Spatially discontinuous permafrost conditions frequently occur in the European Alps. How soils under such conditions have evolved and how they may react to climate warming is largely unknown. This study focuses on the comparison of nearby soils that are characterised by the presence or absence of permafrost (active-layer thickness: 2-3 m) in the alpine (tundra) and subalpine (forest) range of the Eastern Swiss Alps using a multi-method (geochemical and mineralogical) approach. Moreover, a new non-steady-state concept was applied to determine rates of chemical weathering, soil erosion, soil formation, soil denudation, and soil production. Long-term chemical weathering rates, soil formation and erosion rates were assessed by using immobile elements, fine-earth stocks and meteoric 10Be. In addition, the weathering index (K + Ca)/Ti, the amount of Fe- and Al-oxyhydroxides and clay minerals characteristics were considered. All methods indicated that the differences between permafrost-affected and non-permafrost-affected soils were small. Furthermore, the soils did not uniformly differ in their weathering behaviour. A tendency towards less intense weathering in soils that were affected by permafrost was noted: at most sites, weathering rates, the proportion of oxyhydroxides and the weathering stage of clay minerals were lower in permafrost soils. In part, erosion rates were higher at the permafrost sites and accounted for 79-97% of the denudation rates. In general, soil formation rates (8.8-86.7 t/km2/yr) were in the expected range for Alpine soils. Independent of permafrost conditions, it seems that the local microenvironment (particularly vegetation and subsequently soil organic matter) has strongly influenced denudation rates. As the climate has varied since the beginning of soil evolution, the conditions for soil formation and weathering were not stable over time. Soil evolution in high Alpine settings is complex owing to, among others, spatio-temporal variations of permafrost conditions and thus climate. This makes predictions of future behaviour very difficult. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Towards the end of the last glacial cycle, repeated re-advances of valley glaciers in the European Alps combined with periglacial processes led to the formation of a variety of climate-related landforms. Independent age measurements of moraines and rock glacier lobes using both in-situ produced and meteoric 10Be allows for the use of soil formation as an age proxy. In this complementary study we present chemical and mineralogical data from five Podzols from Val Mulix in Eastern Switzerland. Two of them developed on granitic Lateglacial moraines (14.9ka and 10.7ka, respectively) and three were sampled on lobes of a morphostratigraphically connected relict rock glacier, covering an age range of approx. 10.7ka to 8.6ka. Besides the evaluation of the suitability of selected pedosignatures for a relative age separation, we hypothesised that these pedosignatures should give further information about the evolution of the specific sites. Although the soils had a high skeleton content and the oldest soil started its development in a slightly colder climatic phase, typical weathering trends could still be detected. Whereas weathering indices such as the (K+Ca)/Ti ratio or the B-index reflect time trends reasonably well, the mineralogical composition of the fine earth and clay fraction yielded a slightly more inconsistent picture; to a lesser extent, some inconsistencies were also exhibited when using the weathering mass balance approach. This is especially true for the relict rock glacier and it supports the suggested complex development history of these soils as well as the presence of pre-weathered material. Techniques that include several surface soil horizons and the soil skeleton such as the (K+Ca)/Ti ratio, the B-index and the mass balance approach gave more robust results (in terms of the expected chronology) than the ones that only referred to single horizons (clay mineralogy). Errors or variations due to potential reallocation processes within the soil horizons but without a prominent change of the overall soil characteristics are minimised using such an approach. Weathering indexes and the clay mineral assemblage provided a differentiation of soils even within a relatively narrow time range and gave insight into processes that have occurred at the specific sites. The combined relative-numerical dating approach used here not only enables an extended interpretation and mutual control, but ultimately leads to a better understanding of landscape reconstruction and evolution. [Copyright &y& Elsevier]

Several bacterial strains isolated from granitic rock material in front of the Damma glacier (Central Swiss Alps) were shown (i) to grow in the presence of granite powder and a glucose-NH4CI minimal medium without additional macro- or micronutrjents and (ii) to produce weathering-associated agents. In particular, four bacterial isolates (one isolate each of Arthrobacter sp., Janthinobacterium sp., Leifsonia sp., and Polaromonas sp.) were weathering associated. In comparison to what was observed in abiotic experiments, the presence of these strains caused a significant increase of granite dissolution (as measured by the release of Fe, Ca, K, Mg, and Mn). These most promising weathering-associated bacterial species exhibited four main features rendering them more efficient in mineral dissolution than the other investigated isolates: (i) a major part of their bacterial cells was attached to the granite surfaces and not suspended in solution, (ii) they secreted the largest amounts of oxalic acid, (iii) they lowered the pH of the solution, and (iv) they formed significant amounts of HCN. As far as we know, this is the first report showing that the combined action of oxalic acid and HCN appears to be associated with enhanced elemental release from granite, in particular of Fe. This suggests that extensive microbial colonization of the granite surfaces could play a crucial role in the initial soil formation in previously glaciated mountain areas. [ABSTRACT FROM AUTHOR]