Mitteltiefe geothermische Anlagen in Sachsen

Ziel des Forschungsvorhabens war es, die Einsatzpotentiale mitteltiefer geothermischer Systeme für die sächsischen Ballungsräume Leipzig, Dresden und Chemnitz detailliert zu untersuchen, Kostenvergleiche durchzuführen und Handlungsempfehlungen für potenzielle Projekte abzuleiten. Für jeden Musterstandort wurde eine mitteltiefe Erdwärmesondenanlage vollständig geplant. Mitteltiefe Erdwärmeanlagen können demzufolge eine wirtschaftliche Alternative zur konventionellen Klimatisierung/Temperierung von Gebäuden darstellen. Im vorliegenden Forschungsbericht sind Schritte für Planung, bauliche Umsetzung und Überwachung zusammengefasst. Auch Investitions- und Betriebskosten werden abgeschätzt. Damit können die Ergebnisse des Forschungsvorhabens als Entscheidungshilfe für Behörden, Investoren und Fachplaner herangezogen werden. Redaktionsschluss: 31.08.202

Emplacement and segment geometry of large, high-viscosity magmatic sheets

This project and Tobias Schmiedel are funded by the Knut and Alice Wallenberg Foundation through a Wallenberg Academy Fellow grant to Steffi Burchardt (grant No. KAW 2017.0153).Understanding magma transport in sheet intrusions is crucial to interpreting volcanic unrest. Studies of dyke emplacement and geometry focus predominantly on low-viscosity, mafic dykes. Here, we present an in-depth study of two high-viscosity dykes (106 Pa·s) in the Chachahuén volcano, Argentina, the Great Dyke and the Sosa Dyke. To quantify dyke geometries, magma flow indicators, and magma viscosity, we combine photogrammetry, microstructural analysis, igneous petrology, Fourier-Transform-Infrared-Spectroscopy, and Anisotropy of Magnetic Susceptibility (AMS). Our results show that the dykes consist of 3 to 8 mappable segments up to 2 km long. Segments often end in a bifurcation, and segment tips are predominantly oval, but elliptical tips occur in the outermost segments of the Great Dyke. Furthermore, variations in host rocks have no observable impact on dyke geometry. AMS fabrics and other flow indicators in the Sosa Dyke show lateral magma flow in contrast to the vertical flow suggested by the segment geometries. A comparison with segment geometries of low-viscosity dykes shows that our high-viscosity dykes follow the same geometrical trend. In fact, the data compilation supports that dyke segment and tip geometries reflect different stages in dyke emplacement, questioning the current usage for final sheet geometries as proxies for emplacement mechanism.Publisher PDFPeer reviewe

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems

Statistical Techniques and Participatory Approaches for the Compilation of the European Internal Market Index 1992-2001

Abstract not availableJRC.G-Institute for the Protection and the Security of the Citizen (Ispra

Impact of forest fires on the long-term dynamics of near-natural Scots pine forests (Leucobryo-Pinetum) in Saxon Switzerland National Park (Saxony, Germany)

Verglichen mit Laubwaldgesellschaften sind Langzeitstudien über Waldkiefern-Bestände (Pinus sylvestris L.) in Mitteleuropa selten und die Sukzessionsdynamik von Kiefernwäldern wurden in dieser Region bisher kaum untersucht. Obwohl es sich um den am stärksten von Feuern betroffenen Waldtyp in Mitteleuropa handelt, liegen lediglich wenige Daten zu den Auswirkungen von Bränden auf die Vegetation von mitteleuropäischen Kiefernwäldern vor. Außerdem sind Kiefernwälder in besonders hohem Maße von Eutrophierung betroffen, die starke Veränderungen in der Vegetation verursachen können. In der vorliegenden Studie wurden naturnahe, waldbrandbeeinflusste Kiefernwälder (Leucobryo-Pinetum) im Nationalpark Sächsische Schweiz (Sachsen, Deutschland) untersucht. Dauerbeobachtungsflächen wurden mit bis zu vier Wiederholungen von Vegetationsaufnahmen seit 1963 untersucht. Gemäß den einzelnen Waldbrandereignissen und dem Jahr der Flächeneinrichtung wurden drei Zeitreihen analysiert. (A: 1963-2012, Feuer: 1948/1953); B: 2002-2014, Feuer: 1993; C: 2002-2014, Feuer: 2000), Hierbei wurden unerwartet geringe Veränderungen der Pflanzendiversität und des Artenspektrums der Vegetation gefunden. Nur wenige Arten wurden kurzzeitig durch Waldbrände gefördert, und lediglich einzelne Arten zeigten signifikante Veränderungen in ihren Deckungsgraden in Abhängigkeit vom Waldbrandereignis. Nitrophyten fehlten weitgehend. Offenbar liegen die lokalen Stickstoff-Depositionsraten noch deutlich unter den für einen Vegetationswandel kritischen Werten. Verglichen mit Kiefernforsten und durch traditionelle Nutzung entstandenen Kiefernwäldern stellen naturnahe Bestände des Leucobryo-Pinetum einen relativ stabilen Waldtyp dar, der nur wenig von Waldbränden beeinflusst wird und langfristig nur einer trägen Sukzession unterliegt.Compared to deciduous forest associations, long-term investigations of Scots pine (Pinus sylvestris L.) forests in Central Europe are scarce and their succession dynamics are not well studied. Although being the most fire-prone forest type in Central Europe, there is also a lack of data on the long-term effects of forest fires on the vegetation of Central European Scots Pine forests. Additionally, pine stands are highly vulnerable to eutrophication, strongly altering vegetation. Therefore, we studied near-natural, fire-affected Scots pine forests (Leucobryo-Pinetum) within Saxon Switzerland National Park (Saxony federal state, Germany) by permanent observation plots. Plots where surveyed by vegeta-tion relevés repeated up to four times. Based on the date of the relevant fire events and the year of plot establishment, we analysed three time series (A: 1963–2012, fire 1948/1953); B: 2002–2014, fire: 1993; C: 2002–2014, fire: 2000). Unexpectedly, we found low variation in plant diversity and a low species turnover across the time series. Only few species where propagated by the forest fire events in the short run, few species showed significant cover variations depending on the time passed since the forest fire. Nitrophytic species where nearly absent. The low eutrophication signal in the vegetation is attributed to nitrogen deposition rates below critical rates for species turnover. Compared to Scots pine plantations and Scots pine forests originating from extensive management, near natural stands of the Leucobryo-Pinetum appear as a relatively stable forest type, which is only shortly affected by local forest fires and underlies stagnant succession dynamics in the long run

Macrocyclic Donor–Acceptor Dyads Composed of a Perylene Bisimide Dye Surrounded by Oligothiophene Bridges

Two macrocyclic architectures comprising oligothiophene strands that connect the imide positions of a perylene bisimide (PBI) dye have been synthesized via a platinum-mediated cross-coupling strategy. The crystal structure of the double bridged PBI reveals all syn-arranged thiophene units that completely enclose the planar PBI chromophore via a 12-membered macrocycle. The target structures were characterized by steady-state UV/Vis absorption, fluorescence and transient absorption spectroscopy, as well as cyclic and differential pulse voltammetry. Both donor–acceptor dyads show ultrafast Förster Resonance Energy Transfer and photoinduced electron transfer, thereby leading to extremely low fluorescence quantum yields even in the lowest polarity cyclohexane solvent

Macrocyclic donor-acceptor dyads composed of a perylene bisimide dye surrounded by oligothiophene bridges

Two macrocyclic architectures comprising oligothiophene strands that connect the imide positions of a perylene bisimide (PBI) dye have been synthesized via a platinum-mediated cross-coupling strategy. The crystal structure of the double bridged PBI reveals all syn-arranged thiophene units that completely enclose the planar PBI chromophore via a 12-membered macrocycle. The target structures were characterized by steady-state UV/Vis absorption, fluorescence and transient absorption spectroscopy, as well as cyclic and differential pulse voltammetry. Both donor–acceptor dyads show ultrafast Förster Resonance Energy Transfer and photoinduced electron transfer, thereby leading to extremely low fluorescence quantum yields even in the lowest polarity cyclohexane solvent