Debris cover on glaciers is an important component of glacial systems as it influences climate–glacier dynamics and thus the lifespan of glaciers. Increasing air temperatures, permafrost thaw and ...rock faces freshly exposed by glacier downwasting in accumulation zones result in increased rockfall activity and debris input. In the ablation zone, negative mass balances result in an enhanced melt‐out of englacial debris. Glacier debris cover thus represents a clear signal of climate warming in mountain areas. To assess the temporal development of debris on glaciers of the Eastern Alps, Austria, we mapped debris cover on 255 glaciers using Landsat data at three time steps. We applied a ratio‐based threshold classification technique and analysed glacier catchment characteristics to understand debris sources better. Across the Austrian Alps, debris cover increased by more than 10% between 1996 and 2015 while glaciers retreated in response to climate warming. Debris cover distribution shows significant regional variability, with some mountain ranges being characterised by mean debris cover on glaciers of up to 75%. We also observed a general rise of the mean elevation of debris cover on glaciers in Austria. The debris cover distribution and dynamics are highly variable due to topographic, lithological and structural settings that determine the amount of debris delivered to and stored in the glacier system. Despite strong variation in debris cover, all glaciers investigated melted at increasing rates. We conclude that the retarding effects of debris cover on the mass balance and melt rate of Austrian glaciers is strongly subdued compared with other mountain areas. The study indicates that, if this trend continues, many glaciers in Austria may become fully debris covered. However, since debris cover seems to have little impact on melt rates, this would not lead to prolonged existence of debris‐covered ice compared with clean ice glaciers.
Across the Austrian Alps, debris cover on glaciers increased significantly between 1996 and 2015 while glaciers retreated inresponse to climate warming. Distribution and dynamics of debris cover are found being highly variable due to topographic,lithological and structural settings. We conclude that, if this trend continues, many glaciers in Austria may become fully debriscovered. Debris cover seems to have little impact on melt rates and will not extend the existence of debris‐covered ice compared with clean ice glaciers.
glaciers.
The emergence of glacial lakes is a significant consequence of global climate change in high mountain regions. Recent developments in ice thickness modelling combined with high‐resolution glacier ...surface data led to the generation of modelling approaches to simulate the ice‐free bedrock topography below current glaciers and to detect potential glacier bed overdeepenings (GBO) that may form into future lakes. We simulated the subglacial topography in the Austrian Alps using two different ice thickness models. Glaciers in the study area differ significantly from glaciers investigated in previous studies on potential future lakes because of their in general small size and location often restricted to cirques. The aim of this study is to estimate the number and location of potential future lakes in Austria. We tested the performance of ice thickness models for modelling of potential future lakes in an environment dominated by mountain glaciers that are under high stress of climate change. Modelling results are compared with lakes that evolved since the modelling periods and with data on subglacial topography derived from geophysical surveys. Results show significant differences in model performance concerning the total ice volume and the number of simulated GBOs. The number and total area of the modelled GBOs is overestimated, compared with the number of lakes that have evolved in the past. Most GBOs are simulated for valley type glaciers, even though most glaciers are mountain types. This does not match with the location of existing glacial lakes that are dominantly found in cirques. We ascertain that this modelling approach performs better on large valley type glaciers and less well on mountain glaciers. Intersecting the modelling runs indicates that up to 42 new lakes may form within 23 glaciers in Austria covering a total area of 2 km2.
We simulated the subglacial topography in the Austrian Alps in order to assess the location of subglacial depressions that may turn into glacial lakes when glaciers have melted. We ascertain that the modelling approach performs better on large valley type glaciers and less well on cirque glaciers. Intersecting the different modelling runs indicates that up to 42 new lakes may form within 23 glaciers in Austria covering a total area of 2 km².
The complex interrelation between plants and geomorphic processes is described in the concept of biogeomorphic succession. While ecological research on succession and community assembly has ...transitioned towards functional approaches, studies on functional diversity in biogeomorphic settings, particularly in glacier forelands, remain limited. In this study, we investigated abundance of vascular plant species and functional traits in an alpine glacier foreland using data from 199 plots. Our objective was to unravel the development of functional diversity during biogeomorphic succession. Specifically, the study determined whether structural shifts in functional diversity are associated with stability thresholds related to plant cover, geomorphic influence, and examined trait spectra for stages of biogeomorphic succession. Our findings revealed a nonlinear trajectory of functional diversity along the plant cover gradient, marked by two distinct structural shifts at 30% and 74% cover, corresponding to established stability thresholds. Along the gradient of geomorphic influence, we observed an increase in functional diversity until 54% of the plot area was affected, beyond which functional diversity declined below the initial level. The analysis of community‐weighted means of traits across four stages of biogeomorphic succession determined by plant cover and absence and presence of geomorphic influence revealed significant differences in trait values. In the transition to the biogeomorphic stage, associated with the identified initial structural shift, there is a shift from a prevalence of above‐ground adaptation and reproductive traits, such as leaf longevity, structure, growth form and mixed reproductive strategies, to an increased dominance of competitor species and traits related to below‐ground structures, including root type and structures, as well as vegetative reproduction. Our results contribute to understanding the relationship between vegetation succession and geomorphic influence by linking them to plant functional traits. This study advances beyond traditional taxonomic investigations by emphasizing functional approaches to biogeomorphic succession. Moreover, the functional trait data used in this study, easily downloadable from a public repository, can serve as a valuable template for future research in (bio)geomorphology, along with the employed methodologies.
This study indicates functional changes of alpine plants at known stability and competition thresholds during biogeomorphic succession in glacier forelands, utilizing openly accessible trait data. Unlike earlier studies that focused predominantly on taxonomic analyses of biogeomorphic succession, this research underscores significant shifts in the dominance of certain traits during this process.
Proglacial slopes provide suitable conditions for observing the co‐development of abiotic and biotic systems. The frequency and magnitude of geomorphic processes and plant composition govern this ...interplay, which is described in the model of biogeomorphic succession. In high mountain environments, this model has only been tested in a limited number of studies. The study aimed to quantify small‐scale sediment transport via erosion plots along a plant cover gradient and to investigate the influence of sediment transport on plant communities. We aimed to generate quantitative data to test existing biogeomorphic models. Small‐scale biogeomorphic interactions were investigated on 30 test plots of 2 × 3 m size on proglacial slopes of the Gepatschferner (Kaunertal) in the Austrian Alps during the snow‐free summer months over three consecutive years. The experimental plots were established on slopes along a plant cover gradient. A detailed vegetation survey was carried out to capture biotic conditions, and specific sediment yield was measured at each plot. Species abundance and composition at each site reflected successional stages. Additional environmental parameters, such as terrain age, geomorphometry, grain size distribution, soil nutrients, and precipitation, were also included in the analyses. We observed two pronounced declines in geomorphic activity on plots with both above 30% and above 75% plant cover. Nonmetric multidimensional scaling showed distinct clusters of vegetation composition that mainly followed a successional gradient. Sites that were affected by high‐magnitude geomorphic events showed different environmental conditions and species communities. Quantified process rates and observed species composition support the concept of biogeomorphic succession. The findings help to narrow down a biogeomorphic feedback window.
Investigation of small‐scale specific sediment yield showed two stability thresholds at 30% and 75% plant cover. Species composition showed stages of biogeomorphic succession and the influence of geomorphic processes on successional time.
We present a detailed geomorphological map (1:5000-scale) of a middle mountainous area in Jena, Germany. To overcome limitations and to extend the possibility of manually digital mapping in a ...structural way, we propose an approach using geographic information systems (GIS) and high-resolution digital data. The geomorphological map features were extracted by manually interpreting and analyzing the combination of different data sources using light detection and ranging (LiDAR) data. A combination of topographic and geological maps, digital orthophotos (DOPs), Google Earth images, field investigations, and derivatives from digital terrain models (DTMs) revealed that it is possible to generate the geomorphologic features involved in classical mapping approaches. LiDAR-DTM and land surface parameters (LSPs) can provide better results when incorporating the visual interpretation of multidirectional hillshade and LSP composite maps.Findings enabled us to systematically delineate landforms and geomorphological process domains. We suggest that further use of digital data should be undertaken to support analysis and applications.
In high‐alpine valleys undergoing glacier retreat, the spatial distribution of talus slopes and their sediments have been frequently used as a proxy for rockfall activity. However, within this ...‘sediment‐dominated’ research focus, the deglaciated source rockwalls are often portrayed in an oversimplified way. Here, we investigate 12 rockwall‐talus systems in three glaciated hanging valleys in the Swiss Alps and explore the role of source rockwalls on the spatial pattern of talus slopes and their paraglacial rockfall activity. Data from field‐based talus slope surveys, rockwall geotechnical studies, rock temperature monitoring, frost cracking modeling and GIS‐based topoclimatic analyses are evaluated by ergodic reasoning in a principal component analysis to identify patterns of rockwall‐talus systems with respect to their topoclimatic, rock mechanical and paraglacial controls. The results show that four main factors (frost cracking, permafrost probability, rockwall morphometry and mechanical preconditioning by rock mass strength and joint orientation) combine to dictate the paraglacial and spatial variability of sediment production, rockfall activity and block size. Our study demonstrates that more emphasis must be given to source rockwalls as their instability and weathering are directly linked to landform and material characteristics of talus deposits.
Fibroblast growth factor-inducible 14 (Fn14) is a member of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF) and is activated by its ligand TNF-like weak inducer of apoptosis (TWEAK). ...The latter occurs as a homotrimeric molecule in a soluble and a membrane-bound form. Soluble TWEAK (sTWEAK) activates the weakly inflammatory alternative NF-κB pathway and sensitizes for TNF-induced cell death while membrane TWEAK (memTWEAK) triggers additionally robust activation of the classical NF-κB pathway and various MAP kinase cascades. Fn14 expression is limited in adult organisms but becomes strongly induced in non-hematopoietic cells by a variety of growth factors, cytokines and physical stressors (e.g., hypoxia, irradiation). Since all these Fn14-inducing factors are frequently also present in the tumor microenvironment, Fn14 is regularly found to be expressed by non-hematopoietic cells of the tumor microenvironment and most solid tumor cells. In general, there are three possibilities how the tumor-Fn14 linkage could be taken into consideration for tumor therapy. First, by exploitation of the cancer associated expression of Fn14 to direct cytotoxic activities (antibody-dependent cell-mediated cytotoxicity (ADCC), cytotoxic payloads, CAR T-cells) to the tumor, second by blockade of potential protumoral activities of the TWEAK/Fn14 system, and third, by stimulation of Fn14 which not only triggers proinflammtory activities but also sensitizes cells for apoptotic and necroptotic cell death. Based on a brief description of the biology of the TWEAK/Fn14 system and Fn14 signaling, we discuss the features of the most relevant Fn14-targeting biologicals and review the preclinical data obtained with these reagents. In particular, we address problems and limitations which became evident in the preclinical studies with Fn14-targeting biologicals and debate possibilities how they could be overcome.
Currently ketogenic diets (KDs) are hyped as an anti-tumor intervention aimed at exploiting the metabolic abnormalities of cancer cells. However, while data in humans is sparse, translation of murine ...tumor models to the clinic is further hampered by small sample sizes, heterogeneous settings and mixed results concerning tumor growth retardation. The aim was therefore to synthesize the evidence for a growth inhibiting effect of KDs when used as a monotherapy in mice.
We conducted a Bayesian random effects meta-analysis on all studies assessing the survival (defined as the time to reach a pre-defined endpoint such as tumor volume) of mice on an unrestricted KD compared to a high carbohydrate standard diet (SD). For 12 studies meeting the inclusion criteria either a mean survival time ratio (MR) or hazard ratio (HR) between the KD and SD groups could be obtained. The posterior estimates for the MR and HR averaged over four priors on the between-study heterogeneity τ2 were MR = 0.85 (95% highest posterior density interval (HPDI) = 0.73, 0.97) and HR = 0.55 (95% HPDI = 0.26, 0.87), indicating a significant overall benefit of the KD in terms of prolonged mean survival times and reduced hazard rate. All studies that used a brain tumor model also chose a late starting point for the KD (at least one day after tumor initiation) which accounted for 26% of the heterogeneity. In this subgroup the KD was less effective (MR = 0.89, 95% HPDI = 0.76, 1.04).
There was an overall tumor growth delaying effect of unrestricted KDs in mice. Future experiments should aim at differentiating the effects of KD timing versus tumor location, since external evidence is currently consistent with an influence of both of these factors.
Soil erosion is a severe threat for ecosystems and anthropogenic infrastructure. Glaciers are retreating rapidly due to global warming and the receding ice leaves unvegetated depositions of sediment, ...which are prone to mobilisation during precipitation events. Vegetation is known to serve as erosion protection, but how above- and belowground plant traits, vegetation cover and plant diversity on community level are jointly affecting erosion is unclear. Additionally, soil microbial communities may have effects on slope stability by promoting plant growth and function. We measured sediment transport on 30 plots of 2 × 3 m size on proglacial slopes of the Gepatschferner glacier (Kaunertal, Austria) over three years in a natural pristine high alpine environment. Vegetation cover, species abundances and relevant above- and belowground traits were measured for each occurring plant species on community level. Path model analysis revealed that dense and species-rich plant cover characterized by specific plant growth strategies and trait diversity was best suited to decrease erosion. Vegetation properties were also closely linked to the composition of soil microbial communities characterised by next generation amplicon sequencing, which may facilitate soil formation and further enhance the plants’ soil stabilising potential. Our study illustrates that erosion control may benefit from a high vegetation cover, which is facilitated by diverse plant communities with complementary morphological traits. These vegetation properties also affect soil microbiota, but their impact on slope protection in combination with the vegetation remains to be elucidated. Our findings may inform nature-based solutions against erosion such as revegetation of alpine slopes using specific seed mixtures.
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