Using nuclear power for civil energy generation was a promising idea in the second half of the 20th century. Compared to fossil fuels, nuclear power results in almost no \(\mathrm{CO}_{2}\) bearing ...emissions, which are known to have triggered and enhanced the global climate change. However, nuclear power bears other risks, e.g. environmental and health damage caused by radiation, unwanted release of nuclides being transported by water, accidents of nuclear power plants, and not to mention the possibility of non-intended military use. In any case, generating power from nuclear fission will always produce radiating waste, albeit in small amounts. Due to its longevity, this waste is a significant challenge for scientists, politicians and for the international social community to find a repository, which can be considered safe for millions of years and is accepted by the public. As the general consensus is that the rocks of earth crust’s are the best option for a controlled storage, scientists including geologists, geophysicists and hydrogeologists are looking worldwide for safe underground repository sites. Given different political preconditions, the nations, especially in the European Union, have developed different strategies. The following article intends to describe the current strategy in Germany, which is based on a specific “Act on the search for and selection of a site for a final repository for highly radioactive waste” (in short: Site Selection Act) and attempts to learn from mistakes in the seventies. It is our strong conviction that fundamental geological aspects are as important as essential societal principles in order to gain maximum public acceptance.
Chronic nitrogen (N) deposition is a threat to biodiversity that results from the eutrophication of ecosystems. We studied long‐term monitoring data from 28 forest sites with a total of 1,335 ...permanent forest floor vegetation plots from northern Fennoscandia to southern Italy to analyse temporal trends in vascular plant species cover and diversity. We found that the cover of plant species which prefer nutrient‐poor soils (oligotrophic species) decreased the more the measured N deposition exceeded the empirical critical load (CL) for eutrophication effects (P = 0.002). Although species preferring nutrient‐rich sites (eutrophic species) did not experience a significantly increase in cover (P = 0.440), in comparison to oligotrophic species they had a marginally higher proportion among new occurring species (P = 0.091). The observed gradual replacement of oligotrophic species by eutrophic species as a response to N deposition seems to be a general pattern, as it was consistent on the European scale. Contrary to species cover changes, neither the decrease in species richness nor of homogeneity correlated with nitrogen CL exceedance (ExCLempN). We assume that the lack of diversity changes resulted from the restricted time period of our observations. Although existing habitat‐specific empirical CL still hold some uncertainty, we exemplify that they are useful indicators for the sensitivity of forest floor vegetation to N deposition.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We examine the statistical distribution of large‐scale Birkeland currents measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment in four unique categories of ...geomagnetic activity for the first time: quiet times, storm times, quiet‐time substorms, and storm‐time substorms. A novel method is employed to sort data into one of these four categories, and the categorizations are provided for future research. The mean current density is largest during substorms and its standard deviation is largest during geomagnetic storms. Current densities which are above a low threshold are more likely during substorms, but extreme currents are far more likely during geomagnetic storms, consistent with a paradigm in which geomagnetic storms represent periods of enhanced variability over quiet times. We demonstrate that extreme currents are most likely to flow within the Region 2 current during geomagnetic storms. This is unexpected in a paradigm of the current systems in which Region 1 current is generally larger.
Plain Language Summary
We take measurements from a set of 66 spacecraft orbiting Earth to look at electric currents that flow along Earth's magnetic field lines. We look at different types of space weather called “geomagnetic storms” and “substorms,” and combine methods to detect when those types of space weather happen. We use our combined method to separate our measurements into the different types of space weather, and then we look at how strong the currents are during each type of space weather. We plot histograms of the strengths and then use those histograms to work out the underlying mathematics of the strengths: we can then plot further graphs showing how those underlying mathematics change. We then work out when the very strongest currents are likely to flow, and during which type of space weather this occurs, which is useful both for understanding the system and for mitigating against the risks of space weather.
Key Points
Geomagnetic storms are more likely than substorms to drive extreme field‐aligned current densities
Extreme current densities are most likely on the dayside and least likely within 3 hr of midnight
The highest probabilities of extreme current densities occur in Region 2 currents during geomagnetic storms
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Zusammenfassung
Das vorliegende Essay gibt einen Überblick zum Standortauswahlprozess für die Endlagerung des hochradioaktiven Abfalls in der Bundesrepublik Deutschland. Dieses Verfahren stellt einen ...Paradigmenwechsel gegenüber dem früheren Versuch der Ausweisung eines Standortes dar, indem zunächst einzig geologische Kriterien hinsichtlich der Sicherheit der Einlagerung und nicht politisch-wirtschaftliche Einzelinteressen von Regionen entscheidend sein sollen. Der aktuelle Stand der Forschung bildet weitergehende Wissensbedarfe gut ab. Derzeit besonders diskutierte Aspekte im Rahmen der Einengung der großen Teilgebiete auf Standortregionen zur übertägigen Erkundung werden angesprochen.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Irrigation water is a major source of fresh produce contamination with undesired microorganisms including antibiotic-resistant bacteria (ARB), and contaminated fresh produce can transfer ARB to the ...consumer especially when consumed raw. Nevertheless, no legal guidelines exist so far regulating quality of irrigation water with respect to ARB. We therefore examined irrigation water from major vegetable growing areas for occurrence of antibiotic-resistant indicator bacteria Escherichia coli and Enterococcus spp., including extended-spectrum β-lactamase (ESBL)-producing E. coli and vancomycin-resistant Enterococcus spp. Occurrence of ARB strains was compared to total numbers of the respective species. We categorized water samples according to total numbers and found that categories with higher total E. coli or Enterococcus spp. numbers generally had an increased proportion of respective ARB-positive samples. We further detected high prevalence of ESBL-producing E. coli with eight positive samples of thirty-six (22%), while two presumptive vancomycin-resistant Enterococcus spp. were vancomycin-susceptible in confirmatory tests. In disk diffusion assays all ESBL-producing E. coli were multidrug-resistant (n = 21) and whole-genome sequencing of selected strains revealed a multitude of transmissible resistance genes (ARG), with blaCTX-M-1 (4 of 11) and blaCTX-M-15 (3 of 11) as the most frequent ESBL genes. Overall, the increased occurrence of indicator ARB with increased total indicator bacteria suggests that the latter might be a suitable estimate for presence of respective ARB strains. Finally, the high prevalence of ESBL-producing E. coli with transmissible ARG emphasizes the need to establish legal critical values and monitoring guidelines for ARB in irrigation water.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Forages rich in water‐soluble carbohydrates (WSC) might be an ideal energy source during early lactation, as they provide both energy for milk production and structural fibre to promote ...chewing and rumen buffering. Thus, the aim was to investigate feeding strategies based on high‐quality hay rich in WSC with graded amounts of concentrate on ruminating behaviour, ruminal pH and systemic health variables. Twenty‐four Simmental cows were randomly allocated to four groups beginning 10 days before until 28 days after calving. Diets were 60LQH (60% fibre‐rich hay plus 40% concentrate), 60HQH, 75HQH and 100HQH (60%, 75% and 100% high‐quality hay, plus 40%, 25% and 0% concentrate, respectively). Hay qualities differed in contents of WSC (110 g vs. 198 g of dry matter DM), neutral detergent fibre (646 g vs. 423 g of DM) and crude protein (65 g vs. 223 g of DM). Rumination was recorded using the Rumiwatch system over 4 days during the last week. Weekly serum samples were analysed for the liver enzymes aspartate aminotransferase, glutamate dehydrogenase and γ‐glutamyltransferase and the acute phase proteins serum amyloid A and haptoglobin. Four cows per group received a wireless pH sensor orally placed into the rumen one week before the expected calving date. Daily time spent chewing did not differ between groups. Likewise differences in minimum, maximum and mean pH‐values were not significant, but daily time of reticular pH <6 was longer in cows fed 60LQH compared to cows fed 100HQH (p = 0.043) and in tendency to cows fed 75HQH or 60HQH (p = 0.072 or p = 0.086, respectively). Blood parameters were unaffected by diet. Accordingly the present results demonstrate that feeding hay rich in WSC helped stabilizing the reticuloruminal pH in early lactation dairy cows, even in combination with 40% concentrates in DM.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Monitoring and assessing groundwater quality according to European directives and national regulations is usually based on interpolation techniques, e.g. Kriging. However, contour maps of ...hydrochemical parameters often suggest a spurious local accuracy and can therefore lead to inappropriate action measures. Here, the early concept of extension variance combined with the Voronoi tessellation regionalization is proposed. The mosaic-like representation of pollutant concentrations in Voronoi polygons avoids misinterpretations caused by interpolation. The additional calculation of the extension variance, which is based on fundamental geostatistical assumptions, allows for estimating the probability that a given threshold is exceeded. This concept is further extended to hydraulically delimitable groundwater bodies, thus ensuring that hydraulic boundaries are considered. A method is here described for the assessment of groundwater quality with respect to nitrate concentration in the principal aquifer of the state Mecklenburg-Western Pomerania in Germany.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A well-accepted method for identification of microorganisms uses matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled to analysis software which ...identifies and classifies the organism according to its ribosomal protein spectral profile. The method, called MALDI biotyping, is widely used in clinical diagnostics and has partly replaced conventional microbiological techniques such as biochemical identification due to its shorter time to result (minutes for MALDI biotyping versus hours or days for classical phenotypic or genotypic identification). Besides its utility for identifying bacteria, MS-based identification has been shown to be applicable also to yeasts and molds. A limitation to this method, however, is that accurate identification is most reliably achieved on the species level on the basis of reference mass spectra, making further phylogenetic classification unreliable. Here, it is shown that combining tryptic digestion of the acid/organic solvent extracted (classical biotyping preparation) and resolubilized proteins, nano-liquid chromatography (nano-LC), and subsequent identification of the peptides by MALDI-tandem TOF (MALDI-TOF/TOF) mass spectrometry increases the discrimination power to the level of subspecies. As a proof of concept, using this targeted proteomics workflow, we have identified subspecies-specific biomarker peptides for three Salmonella subspecies, resulting in an extension of the mass range and type of proteins investigated compared to classical MALDI biotyping. This method therefore offers rapid and cost-effective identification and classification of microorganisms at a deeper taxonomic level.
Underground hard coal mining usually disrupts the mechanical equilibrium of rock sequences, creating fractures within minor permeable rocks. The present study employs a dual-continuum model to assess ...how both fractured and porous sandstone media influence the percolation process in postmining setups. To test the approach, the software TOUGH2 was employed to simulate laminar fluid flow in the unsaturated zone of the Ibbenbüren Westfield mining area. Compared to other coal mining districts in Germany, this area is delineated by the topography and local geology, leading to a well-defined hydrogeological framework. Results reveal good agreement between the calculated and measured mine water discharge for the years 2008 and 2017. The constructed model was capable of reproducing the bimodal flow behavior of the adit by coupling a permeable fractured continuum with a low-conductivity rock matrix. While flow from the fractured continuum results in intense discharge events during winter months, the rock matrix determines a smooth discharge limb in summer. The study also evaluates the influence of individual and combined model parameters affecting the simulated curve. A detailed sensitivity analysis displayed the absolute and relative permeability function parameters of both continua among the most susceptible variables. However, a strong a priori knowledge of the value ranges for the matrix continuum helps to reduce the model ambiguity. This allowed for calibration of some of the fractured medium parameters for which sparse or variable data were available. However, the inclusion of the transport component and acquisition of more site-specific data is recommended to reduce their uncertainty.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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