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As peatlands are a major terrestrial sink in the global carbon cycle, gaining understanding of their development and changes throughout time is essential to predict their future carbon budget and potentially mitigate negative influences of climate change. With this aim to understand peat development, many studies have investigated the paleoecological dynamics through the analysis of various proxies, including pollen, macrofossil, elemental, and biomarker analyses. However, as each of these proxies are known to have their own benefits and limitations, examining them in parallel potentially allows for a deeper understanding of these paleoecological dynamics at the peatland and for a systematic comparison of the power of these individual proxies. In this study, we therefore analyzed soil cores from a peatland in Germany (Beerberg, Thuringia) to a) characterize the vegetation dynamics over the course of the peatland development during the late Holocene and b) evaluate to what extent the inclusion of multiple proxies, specifically pollen, macrofossil, and biomarkers, contributes to a deeper understanding of those dynamics and interaction among factors. We found that, despite a major shift in regional forest composition from primarily beech to spruce as well as many indicators of human impact in the region, the local plant population in the Beerberg area remained stable over time following the initial phase of peatland development up until the last couple of centuries. Therefore, little variation could be derived from the paleobotanical data alone. The combination of pollen and macrofossil analyses with the elemental and biomarker analyses enabled further understanding of the site development as these proxies added valuable additional information including the occurrence of climatic variations, such as the Little Ice Age, and more recent disturbances such as drainage and dust deposition. [ABSTRACT FROM AUTHOR]

Only scarce information is available on how organic C is incorporated into the soil during the decay and how (micro) climate influences this process. Therefore, we investigated the effect of exposure and elevation on the organic litter decomposition and C-stabilisation in acidic soils of an Alpine environment. An experiment with artificially C labelled Norway spruce needles was carried out at north- and south-exposed sites between 1200 and 2400 m a.s.l. in the Italian Alps using mesocosms. After 1 year, the C recoveries of the bulk soil were 18.6% at the north-facing slopes and 31.5% at the south-facing slopes. A density fractionation into a light (LF; ≤1.6 g cm) and a heavy fraction (HF; >1.6 g cm) of the soil helped to identify how the applied substrate was stabilised. At the northern slope, 10.5% of the substrate was recovered in the LF and 8.1% in the HF and at the south-facing slope 22.8% in the LF and 8.1% in the HF. The overall C recovery was higher at the south-facing sites due to restricted water availability. Although the climate is humid in the whole area, soil moisture availability becomes more important at south-facing sites due to higher evapotranspiration. However, at sites >1700 m a.s.l, the situation changed, as the northern slope had higher recovery rates. At such altitudes, temperature effects are more dominant. This highlights the importance of locally strongly varying edaphic factors when investigating the carbon cycle. [ABSTRACT FROM AUTHOR]

Purpose: The present work focuses on cold alpine soils of the Altai Mountains (Siberia, Russia). Permafrost is widespread and often occurs at a depth of about 100 cm. The area is characterised by extremely cold winters and cool summers: the aim was consequently to find out whether weathering could be more intense on thermally less unfavoured conditions or whether the abundance of water could be a more important factor. Materials and methods: We investigated 10 soils in a very small area close to a local glacier tongue. Five of the investigated soils were south-facing and the other five north-facing. The soils have the same parent material (mica-rich till), altitude, topography and soil age. The vegetation is alpine grassland that is partially intersected with some juniper and mosses. Soil chemical properties such as organic C, N, soil organic matter quality (using DRIFT), pH value, (oxy)hydroxides, total elemental contents (XRF) and soil micromorphology and mineralogy (using diagnostic treatments and XRD) were determined. The age constraint of the site was given by geomorphic studies together with C dating of a nearby peat bog and the stable organic matter fraction of the soils. Results and discussion: The soils have a Holocene age. The results showed astonishingly clearly-similarly to the European Alps-that the north-facing soils have a higher weathering state. This is expressed by lower pH values, higher oxalate and dithionite extractable Fe, Al, Mn and Si contents, higher C and N concentrations and stocks when compared to the south-facing sites. No statistically significant differences with respect to weathering indexes could be detected. The geochemical evolution of the soils seems to be enhanced at north-facing sites, even though very severe climatic conditions prevail. Furthermore, biodegradation seems to be less pronounced on north-facing compared to south-facing sites as poorly degraded organic matter is accumulated. This gives rise to more organic ligands that promote metal binding and their subsequent eluviation along the soil profile. Conclusions: We consequently must assume that weathering is not limited by low temperatures in the active layer but is rather controlled by soil moisture that seems to be higher during the warmer period in the north-facing soils. [ABSTRACT FROM AUTHOR]

Purpose: Natural rates of soil production or a target soil thickness that allows unrestricted land use can serve as a basis for defining tolerable soil erosion rates. Guidelines for tolerable soil erosion rates in alpine grasslands do not yet exist, partly due to the lack of information of soil formation and production rates. We (i) defined soil formation/production rates for alpine grasslands on siliceous lithology and compared them to measured and modelled soil erosion rates and resulting soil thickness with a special focus on the Urseren Valley (Central Swiss Alps) and (ii) discussed possible trends for alpine soils under global change. Materials and methods: Ranges of soil formation, production and erosion rates were determined using published and our own data for Alpine grasslands soils. Two definitions of tolerable erosion rate were used: when (i) current soil depth remains constant over time; and (ii) at least a minimum soil depth is maintained (minimum thicknesses for individual land uses still need to be defined). Results and discussion: Soil production and related tolerable erosion rates (i.e. 50-90 % of the soil production rate) are a strong function of time. Average soil production rate in alpine areas for relatively old soils (>10-18 kyr) is between 54 (±14) and 113 (±30) t km year, for young soils (>1-10 kyr) between 119 (±44) and 248 (±91) t km year and for very young soils (≤1 kyr) between 415 (±242) and 881 (±520) t km year. Measured recent soil erosion rates in alpine areas at intensively used slopes range from 600 to 3000 t km year. Average catchment values for the Urseren Valley using the model USLE plus soil loss due to landslides resulted in an overall loss of 180 t km year, which considerably exceeds production rates of the soils. Conclusions: The comparison of soil production and erosion rates indicated unsustainable management of grassland soils in the Urseren Valley. Other Alpine regions report similar or even higher erosion rates. Consequently, attention has to be paid to Alpine grasslands used for agricultural purposes because today's soil erosion rates often considerably exceed soil formation, thus resulting in very shallow soils. Future global change is likely to increase soil erosion rates even further. [ABSTRACT FROM AUTHOR]

Abstract: High-mountain soils develop in particularly sensitive environments. Consequently, deciphering and predicting what drives the rates of soil formation in such environments are a major challenge. In terms of soil production or formation from chemical weathering, the predominating perception for high-mountain soils and cold environments is often that the chemical weathering ‘portion’ of soil development is temperature-inhibited, often to the point of non-occurrence. Several concepts exist to determine long-term rates of soil formation and development. We present three different approaches: (1) quantification of soil formation from minimally eroded soils of known age using chronosequences (known surface age and soil thickness — SAST), (2) determination of soil residence times (SRT) and production rates through chemical weathering using (un)stable isotopes (e.g. 230Th/234U activity ratios), and (3) a steady state approach using cosmogenic isotopes (e.g. 10Be). For each method, data from different climate zones, and particularly from high-mountaINS (alpine environment), are compared. The SAST and steady state approach give quite similar results for alpine environments (European Alps and the Wind River Range (Rocky Mountains, USA)). Using the SRT approach, soil formation rates in mountain areas (but having a temperate climate) do not differ greatly from the SAST and steady state approaches. Independent of the chosen approach, the results seem moderately comparable. Soil formation rates in high-mountain areas (alpine climate) range from very low to extremely high values and show a clear decreasing tendency with time. Very young soils have up to 3–4 orders of magnitude higher rates of development than old soils (105 to 106 yr). This apparently is a result of kinetic limits on weathering in regions having young surfaces and supply limits to weathering on old surfaces. Due to the requirement for chemical weathering to occur, soil production rates cannot be infinitely high. Consequently, a speed limit must exist. In the literature, this limit has been set at about 320 to 450t/km2/a. Our results from the SAST approach show, however, that in alpine areas soil formation easily reaches rates of up to 800–2000t/km2/a. These data are consistent with previous studies in mountain regions demonstrating that particularly young soils intensively weather, even under continuous seasonal snowpack and, thus, that the concept of ‘temperature-controlled’ soil development (soil-forming intervals) in alpine regions must be reconsidered. [Copyright &y& Elsevier]

Abstract: Using published and new chronosequence datasets from the European Alps and the Wind River Range (Rocky Mountains, USA), we report for the first time a chronosequence of more than 1Ma for soil organic carbon, nitrogen and organic matter (SOM) fractions from alpine soils. The investigated parameters include total carbon and nitrogen as well as the stable (resistant to H2O2 oxidation) C and N fractions. Time trends were analysed and are reported on the basis of stocks and concentrations. The accumulation rates of C and N strongly decreased with increasing soil age. Differences in trends between the European Alps and the Wind River Range might be attributed to the factor climate. For the drier Wind River Range, an asymptotic value of about 15kgC m−2 was reached after about 15ky while an asymptotic value of 20–25kgC m−2 was measured for the moister European Alps after about 3ky. The difference in N stocks between the two regions was less obvious. For both areas, N was in the range of 0.5–2kgN m−2. Using the exponential decay model, a steady state of C and N (stable and total) concentrations in the topsoil seemed to be reached after <1ky (Alps) and 10ky (Wind River Range). The retardation effect observed for the Wind River Range could probably be due to aeolian influx. For both areas, the asymptotic value of the stable fraction of C and N was in the range of 1–3kgC m−2 and 0.2–0.4kgN m−2, respectively. The stable organic fraction often has an age close to the age of the soils and consequently can reach thousands of years. The relative proportion of N and amides was higher in the stable organic fraction compared to the bulk soil. The sequestration rates of org. C and N in soils of the European Alps and the Wind River Range can reach very high values in very young soils whereas in old soils sequestration rates are several orders of magnitude lower. Old soils often integrate several cold and warm phases and different vegetation types. Nonetheless, the factor Time seems to be very dominant and covers the track of other factors in old soils. [Copyright &y& Elsevier]

Abstract: Investigations in Alpine soils indicate that mineral weathering is much faster in ‘young’ soils (<1000yr) than in ‘old’ soils (∼10,000yr). However, little is known about the initial stages of weathering and soil formation, i.e. during the first decades of soil genesis. In this study we investigated rock-forming minerals weathering at very early stages of soil formation. Due to the continuous retreat of the Morteratsch glacier (Upper Engadine, Swiss Alps), the proglacial area offers a full time sequence from 0 to 150yr old surfaces. A low slope and the absence of glacier which might have interrupted soil formation processes, contributed to the choice of the Morteratsch proglacial valley for this case study. The area is well documented regarding vegetation and soils. The tectonic unit is the Bernina-crystalline, which is mainly constituted of granitoid rocks. Consequently, the glacial till has an acidic character. Mineralogical measurements were carried out on the soil fraction <2mm using XRD and DRIFT for qualitative and quantitative phase analysis. In addition, chemical analyses of the stream water from the main channel, tributaries and of rainwater were performed with a special focus on Ca/Sr and Sr isotope ratios (87Sr/86Sr). Furthermore, the accumulation of organic matter within the time sequence and physical soil properties were measured. Decreasing grain size with time shows active physical weathering processes. Soil organic matter has been accumulated during 150yr at very high rates. Special emphasis has been given to chemical weathering and to the formation and transformation mechanisms of minerals. Of special interest were biotite, chlorite, epidote, plagioclase and calcite. Biotite has been continuously transformed into illite-like components. Within 150yr, the concentration of epidote significantly decreased. The high Ca/Sr as well as 87Sr/86Sr ratios in the stream and spring waters confirmed that Ca bearing minerals are weathering and transforming at very high rates in the proglacial area. Also in cryic, ice-free environments, chemical weathering rates are high leading to the formation and transformation of minerals. Disseminated calcite in granitoid rocks, not confined to sedimentary carbonate rocks, also plays a role in subglacial environments. It is, however, not known for how long such an influence is significant and measurable. The high Ca/Na and Ca/Sr ratio in the stream and tributary waters showed that calcite contributes to the supply of soluble Ca, although the ion activity product calculations clearly demonstrated that the waters were undersaturated with respect to this mineral. [Copyright &y& Elsevier]

Subalpine and Alpine soils in Val di Sole (Trentino, Italy) have been investigated in order to reconstruct vegetation changes and human impact during the Holocene period. Archaeological findings have demonstrated that Alpine sites have been populated since pre-historical times. Humans have had a great impact on the natural landscape evolution. One of the most-used tools has been fire. The use of fire has enabled the landscape to be cleared to provide new pastures for grazing and also to allow it to be used for agricultural purposes. The 14C dating of charcoal fragments found in subalpine and Alpine soils provide information about the type of vegetation, fires, human impact and soil formation throughout the Holocene. The degree of podzolisation indicates weathering effects and provides information about the stability of the surfaces. According to our results, a quick forest expansion establishment phase must have occurred shortly after the Lateglacial around 10 500 cal. BP. Pinus sylvestris, Pinus mugo as well as Larix decidua established in the investigation area in that period. Picea abies had not yet migrated into this region at the transition to the Boreal (around 9000 cal. BP). The vegetation of the investigated area has not substantially changed during the last 10 000 years. Pinus mugo was more widespread in some areas during the Older Atlanticum, and the treeline was about 150 m higher at the end of the Younger Dryas than today. Some other sites were most probably used as pasture during the Bronze Age and later abandoned, leading to a natural reforestation. In the investigated area 13 fire events in the past 10 700 years have been recognised, and seven of them can reasonably be attributed to human origin. [ABSTRACT FROM AUTHOR]

Abstract: The main aim of this study was to examine the influence of exposure and consequently climate, on the chemical weathering of soils which had developed after the ice retreat of the last glaciation in Northern Italy. This was done by comparing soils developing at north- and south-facing sites on siliceous parent material. There is very little data available on weathering rates and organic matter (OM) as a function of climate and exposure in such environments. Weathering rates (elemental leaching) over the whole lifetime of the soils are higher on north-facing sites. Total organic C and N contents, organic matter stocks and organic matter fractions were analysed to decipher the causes of this difference in weathering behaviour. For the organic matter fractions, we compared the easily oxidisable and stable (resistant to H2O2 treatment) organic matter fractions, water-soluble phenolic materials and alkaline-extractable fractions of the various sites. The abundance of soil organic carbon (SOC) tends to have a non-linear climate dependency. The highest amounts of SOC were measured near the timberline. In addition, compared to south-facing sites, soils on north-facing slopes have a higher organic matter content and a significantly lower degree of humification. Undecomposed or weakly degraded organic matter accumulated on north-facing sites due to less favourable thermal conditions and a higher acidity. With northern exposure, fulvic acids were more easily transported within the soil profile than humic acids and predominately gave rise to the migration (eluviation) of Fe and Al compounds due to their –COOH and –OH functional groups. Furthermore, water-soluble phenolic materials, which are more abundant on north-facing sites, have accelerated the leaching of Al. Accumulation of weakly degraded OM and the subsequently higher production of organic ligands have enhanced the eluviation of Fe and Al. Patterns of weathering processes in Alpine environments are strongly linked to biological and (micro)climatic factors which give rise to distinct differences between north- and south-facing sites. [Copyright &y& Elsevier]

Abstract: We investigated the effect of organic matter and weathering on the lability and solid phase speciation of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in two contrasting subalpine regions in the Italian Alps. Cr, Ni and Cu could be linked to weathering. This was not the case for Pb. Since organic matter (OM) influences the solid phase speciation of heavy metals, the total organic C and N content, the C and N content of different density fractions of OM and also of the labile (oxidised by H2O2) and stable (H2O2-resistant) fractions were determined. Soil OM stocks were high and soils on north-facing slopes had more OM than the south-facing sites to which they were paired. Density measurements and the H2O2 fractionation indicated that the higher OM content on north-facing sites was due to an accumulation of weakly degraded organic material. Due to higher weathering intensity on north-facing sites, the abundance of the EDTA-extractable heavy metals was higher than on south-facing sites. All EDTA-extractable heavy metals showed a good correlation to the water-soluble phenolic concentrations which indicates that the metals were probably translocated as metal-organic complexes. Pb and Cu correlate not only to the light (density <1g/cm3) and labile, organic fraction but also to the heavy (density>2g/cm3) and stable fraction. High-mountain ecosystems like the Alps are sensitive to changing environmental conditions such as global warming. A warmer climate and the more favourable conditions it brings for biological activity, especially at cooler sites, will probably lead in the short- to mid-term to an increased loss of accumulated, weakly degraded OM. As the Pb and Cu content is significantly related to the labile organic matter pools, the risk exists that an increase in OM mineralisation could affect the storage capacity and mobility of these metals in soils. [Copyright &y& Elsevier]

Abstract: The present work focuses on the subalpine range of the Italian Alps to determine the influence of aspect and consequently climate on soil humus properties and chemistry. This was done by comparing soils developing in north- and south-facing sites on siliceous parent material. The soils were investigated with respect to the total organic C and N content, C and N contents of organic matter (OM) density fractions and of labile (oxidised by H2O2) and stable (H2O2-resistant) fractions. Further characterisation of OM and the different fractions was performed with Diffuse Reflection Infrared Fourier Transform (DRIFT), Scanning Electron Microscopy/Electron Diffuse Scattering (SEM/EDS) and radiocarbon dating. The soils at north-facing slopes had a higher OM content. Density measurements and the H2O2 fractionation proved that this higher content was primarily due to a more pronounced accumulation of weakly degraded, labile organic materials when compared to the south-facing slopes. Independent of the sites, a large part of OM (around 50% of OM) was fixed in the densest fraction (>2 g/cm3) which correlated well with the abundance of the H2O2-resistant fraction. The 14C ages of the latter were up to 17,000 years, reflecting the presence of stable, refractory OM and the effectiveness of organo-mineral interactions in protecting OM from decay. Podzolisation has been more intense at north-facing sites. Due to the accumulation of weakly degraded OM, eluviation of Fe and Al is strongly enhanced. High-mountain ecosystems like the Alps are very sensitive to changing environmental conditions such as global warming. Especially at cooler sites, the obtained results suggest that a warmer climate, and thus more favourable conditions for biological activity, will lead in the short- to mid-term to an increased loss of accumulated, weakly degraded OM. [Copyright &y& Elsevier]

Abstract: A comparison was made between two soil climosequences on north- and south-facing slopes in northern Italy to determine the influence of slope aspect on soil processes. The climosequences span an elevational gradient ranging from moderate (1200 m a.s.l.) to high alpine (2420 m a.s.l.) climate zones on surfaces having an age of about 15000 years. The soils were investigated with respect to organic C, oxalate and dithionite extractable Fe, Al and Si, elemental losses (Ca, Mg, K, Na, Fe, Al, Si, Mn) and clay minerals. The stocks of soil org. C as well as of oxalate-extractable Fe and Al was greatest in the subalpine zone near the timberline. There are no clear differences in organic C content between the soils on north- and south-facing sites. Fe-oxalate and to a lesser extent Alo-stocks were, however, greater on north-facing sites, indicating that weathering is greater there. Eluviation and illuviation of Al and Fe within the soil profile, typical for podzolisation, was more distinctly expressed on the N slopes. The probability of ITM (Imogolite-type-material) formation in the soil seemed to be greater on south-facing sites. On the north-facing sites, element leaching was most intense in the subalpine zone close to the timberline while on the south-facing sites this was only the case for the base cations. The N slopes exhibited higher leaching of elements which generally indicates a higher weathering intensity. On south-facing sites, typical podzolisation processes were measurable only above 2000 m a.s.l. The development of smectites is also a reflection of the weathering intensity; smectite was discernible in the surface horizon at all sites on N slopes but the highest amount was detected in the sub-alpine climate zone. For the south-facing sites only in the alpine climate zone could smectite be detected. Higher temperatures and an increased number of freeze-thaw cycles on south-facing slopes should theoretically enhance rates of chemical weathering. This could, however, not be confirmed with our measurements. The degree of chemical weathering increases from the south- to the north-facing sites that are characterised by lower temperatures, lower evapotranspiration and consequently by a higher humidity. Although precipitation in Alpine regions is abundant, the availability and flux of water through the soil is the prime factor in weathering intensity. [Copyright &y& Elsevier]

Abstract: A change in environmental conditions may result in altered soil microbial communities in alpine grasslands but the extent and direction of the change is largely unknown. The aim of our study was to investigate (i) differences in soil microbial communities across an elevation gradient of (sub)alpine grassland soils in the Swiss Alps, and (ii) the long-term effect of translocation of soil cores from a higher to a lower elevation site. The translocation of undisturbed soil cores from a high alpine site (2525 m asl) to a subalpine site near the timberline (1895 m asl) induced an effective artificial warming of 3.3 °C. We hypothesized that after longer than a decade, soil microbial community in translocated cores would differ from that at the original site but resemble the community at the new site. Results from soil phospholipid fatty acid (PLFA) analysis confirm significant differences in microbial communities between sites and a shift in total microbial biomass (TMB) and proportional distribution of structural groups in the translocated cores towards the lower elevation community. Patterns related to translocation were also observed as shifts in the fractional biomass of ectomycorrhizal and arbuscular fungi, and in relative contents of several structural groups. Hence, soil microbial community activity and diversity indicate a moderate shift towards new site conditions after 11 years and therefore, our data suggest slow responses of microbial communities to environmental changes in alpine soils. [Copyright &y& Elsevier]

[Display omitted] • The temporal development of nutrient pools can be studied along chronosequences in glacier forelands. • Carbon and nitrogen pools were constantly increasing in the first 10,000 years of landscape development. • Potassium, calcium, magnesium and phosphorous pools peaked after a few hundred years of landscape development. • Bedrock type was a major factor influencing the development of nutrient pools along the proglacial chronosequences. Climate change accelerates glacial retreat worldwide, leaving large areas of unconsolidated terrain. Glacial retreat opens the possibility to study the temporal development of ecosystems, their functions and services by use of a space-for-time-approach. Nutrient pools are important indicators of various ecosystem services as they are critical in supporting the establishment and growth of plant communities, which in turn support the food webs and ecological processes that sustain the ecosystem and downstream communities. In this study, we examined the temporal development of nutrient pools in soils and vegetation communities over a period of more than 10,000 years. We analyzed a comprehensive dataset that embraces repeated measurements of carbon (C), nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg) and phosphorous (P) pools in above- and belowground biomass, litter and soil across alpine chronosequences from two glacier forelands with contrasting bedrocks (silicate vs carbonate). We found that total nutrient pools of C and N, being closely linked to the biomass, increased rapidly along both chronosequences, whereas nutrient pools of K, Ca, Mg, and P were large at first and decreased steadily with time, though at different rates related to the two parent materials. We also observed a remarkable difference in the P pool development between the two glacier forelands. The calcareous soils started out with much more P than the siliceous locations. The plant availability of P was, however, higher in the siliceous soils due to the neutral pH, but decreased with acidification. In the calcareous soils, plant P availability was low at the beginning due to a high pH, but improved as decalcification progressed and pH lowered to slightly acidic conditions. The results of this work highlight that assessing the temporal development of ecosystems services using long-term proglacial chronosequences enhances our understanding of landscape evolution. [ABSTRACT FROM AUTHOR]

Due to their sensitivity to changing environmental conditions sub- and alpine soils are often monitored in the context of climate change, usually, however, neglecting slope exposure. Therefore, we set up a climosequence-approach to study the effect of exposure and, in general, climate, on the microbial biomass and microbial diversity and activity, comprising five pairs of north (N)- and south (S)-facing sites along an altitudinal gradient ranging from 1200 to 2400 m a.s.l. in the Italian Alps (Trentino Alto Adige, Italy). Soil physico-chemical properties were related to microbiological properties (microbial biomass: double strand DNA yield vs. substrate-induced respiration; diversity of bacterial, fungal and archaeal communities: genetic fingerprinting DGGE vs. real-time PCR; microbial activity: basal respiration vs. multiple hydrolytic enzyme assays) to monitor shifts in the diversity and activity of microbial communities as a function of slope exposure and to evaluate the most determinant chemical parameters shaping the soil microbiota. The exposure-effect on several hydrolytic key-enzymes was enzyme-specific: e.g. acid phosphomonoesterase potential activity was more pronounced at the N-facing slope while the activities of alkaline phosphomonoesterase, pyrophosphate-phosphodiesterase and arylsulfatase were higher at the S-facing slope. Furthermore, this exposure-effect was domain-specific: bacteria (S > N, altitude-independent); fungi (N ~ S); and archaea (N > S; altitude-dependent). Additionally, the abiotic parameters shaping the community composition were in general depending on soil depth. Our multidisciplinary approach allowed us to survey the exposure and altitudinal effects on soil physico-chemical and microbiological properties and thus unravel the complex multiple edaphic factor-effects on soil microbiota in mountain ecosystems. [ABSTRACT FROM AUTHOR]

• Formerly glaciated area has a lower degree of soil weathering. • Non-glaciated area has high soil erosion rates (900–1700 [t km−2 yr−1]) • Meteoric 10Be indicates soil mixing. Few data are available on how soil erosion rates compare between surfaces of different ages because short-term processes often overprint the longer-term erosion signal. This study investigated the soil dynamics among two end-member sites, a formerly glaciated ('young', maximum glacial extent at 22–30 ka BP) and a non-glaciated ('old') area at the Serra da Estrela (Portugal). To disentangle soil distribution rates over different timeframes, isotopes for long-term (10Be), mid-term (δ13C) and short-term (239+240Pu) periods were applied together with principles of the percolation theory. The formerly glaciated area has soils with a lower degree of weathering and lower carbon content compared to soils of the 'old', non-glaciated area. The selected isotopes and their distribution along the soil profiles revealed temporal differences in soil mixing process. It is hypothesised that the slightly higher elevation and formerly glaciated sites experienced cryoturbation effects over a longer period, while being less active or absent for the last few decades at the older, non-glaciated soils. The average long-term (millennia) soil erosion rates correspond to the expected higher rates at the younger surface and lower rates at the older surface. Once the formerly glaciated area became ice-free, soil erosion rates were high and decreased giving rise to average long-term rates of 101–140 [t km−2 yr−1] for the older surfaces and 176–248 [t km−2 yr−1] for the younger surfaces. In addition, seasonal freeze–thaw of the soils has persisted over a long period and affected the younger soils more intensively than the older soils. The current (last decades) soil redistribution rates, however, are up to one order of magnitude higher than the millennia rates and are controlled by surface angle and vegetation cover and less by soil texture. The more undulated, non-glaciated older surface had the highest short-term (decades) soil erosion rates in the range of 900–1700 [t km−2 yr−1], exhibits degrading conditions and relatively shallow soils. The younger soils, however, showed short-term (last few decades) average soil deposition rates of ∼ 230 [t km−2 yr−1]. Human impact (bush fires, grazing) is the cause for the currently strong soil degradation at the non-glaciated area. [ABSTRACT FROM AUTHOR]

Climate change and a related increase in temperature, particularly in alpine areas, force both flora and fauna to adapt to the new conditions. These changes should in turn affect soil formation processes. The aim of this study was to identify possible consequences for soils in a dry-alpine region with respect to weathering of primary minerals and leaching of elements under expected vegetation and climate changes. To achieve this, a field empirical approach investigating an altitudinal sequence was used in combination with laboratory weathering experiments simulating several scenarios. The study sites are located in Sinks Canyon and Stough Basin of the Wind River Range, Wyoming, USA. The following sites (from moist to dry with increasing temperature along the sequence) were investigated: 10 soil profiles (Typic Haplocryoll) in a tundra ecotone, 10 soil profiles (Ustic Haplocryoll) in a pine-fir forest and 20 soil profiles (Ustic Argicryoll) in sagebrush. All soils developed on granitoid moraines. Soil mineralogy was analysed using cathodoluminescence and X-ray diffraction. This revealed that biotite and plagioclase were both weathered to smectite while plagioclase also weathered to kaolinite. Cooler, wetter, altitude-dependent conditions promoted weathering of primary minerals. Furthermore, the soils of the tundra and forest zone exhibited a higher acidity and more organic carbon. In a series of wet laboratory batch experiments, materials from topsoils (A horizons) and subsoils (B horizons) in each ecotone were examined alone or in combination with other samples. In a first step, aqueous extracts of the topsoil samples were generated in batch reactors and analysed for the main ions. In a second and a third step the topsoil extracts were reacted with the subsoil samples of the same ecotone, and with the subsoil samples of the ecotones at higher altitude. The total duration of these batch experiments was 1800 h, and the solutes were measured using ICP-OES and ion chromatography. Dissolved Ca, Mg and K were mainly controlled by the chemical weathering of oligoclase, K-feldspar and biotite. With increasing altitude the total concentrations of Ca, Mg and K in the aqueous extracts decreased, the relative ionic contribution from K decreased, while the ionic contribution from Ca increased. Climate change (warming, changed precipitation) potentially will reduce weathering intensity, soil acidity and the content of organic carbon. An altitudinal shift in vegetation due to climate change seems to affect the ionic composition of the soil solution. In the case of a shift from forest to sagebrush and tundra to forest or sagebrush, the relative contribution from K would increase at the expense of Ca. We hypothesise that K will play an important role in future biogeochemical cycles under the assumptions of climate warming and subsequent vegetation shifts to higher altitudes. [ABSTRACT FROM AUTHOR]

Physical and chemical weathering of primary minerals of granitic till in the proglacial area of Morteratsch (Switzerland) was investigated using cathodoluminescence (CL), Nomarski differential interference contrast (DIC) microscopy and scanning electron microscope (SEM–EDX). The investigated time-span ranges from 0 to 140 years of sediment exposure. For the very early stage of weathering or soil formation only little information is available. The main aim of our investigation was consequently to see whether weathering of primary minerals can be detected in such a short time-span using for the first time for soils well-established methods as CL and Nomarski DIC microscopy in geo- and material science such. For that purpose, the fine earth fraction (< 2 mm) of topsoil samples was investigated. Some physical weathering had taken place within 140 years. The delamination of biotite seems to increase with time. SEM and CL analyses also demonstrate early weathering of quartz by evidencing edge pits and structural bonds – such as Si一O一Si in quartz – that start to break and to transform into free radicals. K-feldspar and plagioclase contain Fe. When using Fe3+ as reference point (680–700 nm) to standardise the CL spectra, the Al一O−Al defects of K-feldspar exhibit a relative decrease with time; this was not the case for plagioclase. The CL measurements showed that the investigated apatite contained REE (rare earth elements) in the crystal structure. However, none of the other techniques (DIC, SEM–EDX) was helpful in detecting any specific weathering features for apatite. In the time span of 140 years, epidote weathering was evidenced using XRD in a previous investigation and here using DIC microscopy (morphologic changes). Several mineral changes could be traced within a very short weathering sequence using the applied techniques. These changes include physical (e.g. biotite), chemical or crystal structure (K-feldspar, biotite) features. Such an analytical combination is promising, therefore, for the detection of chemical, physical and mineralogical characteristics and changes in very young glacial sediments. [ABSTRACT FROM AUTHOR]

Soil chronosequences in Alpine areas have often been applied to trace physical, mineralogical and chemical soil properties over time. How the soil pore system of undisturbed soils evolves, however, has not yet been clarified. We therefore investigated two soil chronosequences in the Swiss Alps spanning a time period from a few decades up to the Early Holocene/Late Pleistocene. One soil sequence developed on siliceous parent material in the Sustenpass (proglacial area of the Stein glacier), with soils aged from 30a to 10 ka while the second developed on calcaric parent material in the Klausenpass, with soils aged from 110a to 14 ka (proglacial area of the Griess glacier). We hypothesised that the overall pore size of the topsoil and consequently the relative proportion of macropores decrease with increasing soil age. The pore size characteristics were determined by using X-ray computed tomography. Independent of the parent material (calcareous vs siliceous), macroporosity decreased with time. The greatest changes seemed to occur between the Little Ice Age (LIA) and about 3–4 kyr of soil evolution. Vegetation composition and the functional richness of the plant community exert an influence on soils that developed on siliceous parent material by giving rise to more small pores. Besides pore sizes, pore characteristics also changed with time. In general, the tortuous structure of the soils became more complex with time. The evolution of the pore characteristics such as tortuosity, number and length of pore networks seem also to be related to biologic factors such as root properties, plant species and soil organic matter composition. It remains, however unanswered how these time-dependent biologic factors interact with and influence in detail the pore network. This aspect certainly merits investigation in greater detail in the future. • Moraine soils are valuable tools to investigate Holocene soil evolution. • Physical soil evolution on siliceous and calcareous parent material is different. • Macropore evolution is not continuous over millennia of soil development. • Biotic factors are the main drivers of macropore evolution. • X-ray computed tomography is applicable on high-mountain soils. [ABSTRACT FROM AUTHOR]