http://hdl.handle.net/10900/42126 Tue, 16 Jun 2026 02:11:23 GMT 2026-06-16T02:11:23Z http://hdl.handle.net/10900/180806 Beyond Attribution. Style and Communication in the Visual Culture of the Late Bronze and Iron Age Near East Herrmann, Virginia; Wagner-Durand, Elisabeth The concept of style has been central to art history and archaeology for most of their disciplinary history but has faced serious critique, especially since the 1960s. While some scholars argue for moving beyond style, others maintain its heuristic value. In the context of ancient Near Eastern archaeology and related disciplines, stylistic analysis has always played a vital role, while still oscillating between promise and challenge. Stylistic analysis has been crucial for questions of attribution, i. e. of origins, workshops, craftspeople, dates, contacts, and more. Recent scholarly perspectives have proposed alternative frameworks, such as understanding stylistic similarities as products of historically contingent communities of shared practices. The intertwined relationship between medium, style and meaning has also become an increasingly vital topic. This volume and the 2021 virtual conference on which it is based aimed to explore these developments and encourage discussion of style beyond (mere) attribution. The assembled papers concentrate on the highly interconnected visual cultures of the Late Bronze and Iron Age Near East, but also include a perspective from prehistoric European archaeology. Common themes of power dynamics in the production and consumption of style, rhetorical uses of style for ideological, aesthetic, or programmatic ends, and the embodiment of stylistic production emerge from these contributions. The final chapters take a historiographic view, assessing how far the connoisseurial approaches of the past have taken us and where the future of visual inquiry will lead. Sat, 15 Aug 2026 00:00:00 GMT http://hdl.handle.net/10900/180806 2026-08-15T00:00:00Z http://hdl.handle.net/10900/180799 Adaptation of Agriculture Systems to Metal(loid) and Climate Change Stressors Pieńkowska, Aleksandra The accumulation and mobility of essential and harmful metal(loid)s in agroecosystems greatly influence crop yields, nutritional quality and the stability of soil prokaryotic communities. Agricultural management, particularly through fertilization, represents a major source of metal(loid)s in agriculture soils. However, its long-term effects on metal(loid) mobility and bioavailability under realistic field conditions remain poorly understood. Climate change further complicates these dynamics by altering biogeochemical processes, which govern metal(loid) mobilization in soil and crop physiology, raising critical concerns about potential impacts on nutritional quality. Additional uncertainty arises from the methodological approaches used in climate incubation studies, which often compare present-day soils under current and projected climate conditions. In reality, future soils will already have been shaped by long-term exposure to those climates. This raises a critical question: do incubations using today’s soils provide valid predictions of future biogeochemical responses? This thesis investigates how agricultural management and climate change jointly shape the mobility, accumulation, and biological effects of essential and harmful metal(loid)s in agroecosystems. It aims to: i) assess metal(loid) transfer from soil to crops under different long-term fertilization regimes, including the use of 87Sr/86Sr isotopes as potential tracers for fertilizer-derived metal(loid)s; ii) evaluate the resistance and resilience of soil prokaryotic communities to metal stress across long-term fertilization histories; iii) determine how future climate conditions affect metal(loid) accumulation in crops; iv) assess the extent to which organic farming practices mandated under EU regulations mitigate climate-induced shifts in metal(loid) accumulation and crop productivity; v) evaluate whether climate incubation experiments using present-day soils provide accurate predictions of future biogeochemical responses. This study focuses on both essential (Fe, Zn, Mg, Mn, V) and harmful (Cd, As, Pb) metal(loid)s. To address the research objectives, it integrates long-term field trials, greenhouse climate simulations, and laboratory microcosm incubations with interdisciplinary approaches spanning soil chemistry, crop metal(loid) uptake, and prokaryotic ecology. This thesis demonstrates that agricultural management is a major factor shaping metal(loid) fate in soils and crops. Long-term mineral fertilization significantly increased Cd and As concentrations in wheat grains, with Cd content up by 70% compared with crops harvested from unfertilized control soils. This treatment also reduced the resistance and resilience of soil prokaryotic communities to additional inputs of Cd, Zn, and Pb, impairing prokaryote-mediated nutrient cycling. In contrast, organic fertilization with manure lowered Cd and As accumulation in wheat grains and supported stable prokaryotic communities under further metal stress. Combined mineral–organic treatments buffered negative effects of mineral fertilization on both grain nutritional quality and soil prokaryotic community stability. The 87Sr/86Sr ratios in wheat grains corresponded with those of the fertilizers used, validating their use as tracers for identifying fertilizer sources. In a separate field experiment, EU-certified organic farming reduced the accumulation of both essential Fe and Zn, as well as harmful Cd and As in wheat and barley grains by up to 24%, resulting in mixed effects on grain nutritional quality. This thesis shows that climate change alters metal(loid) dynamics in soils and crops, with outcomes that vary by environmental and experimental context. In a greenhouse experiment simulating future conditions with a substantial 3.4°C increase in atmospheric temperature, a 290 ppmv rise in CO2 concentration, and a 2-percentage-point decrease in soil moisture, spinach accumulated up to 54% more Cd, while Zn, Mg, and Mn responses were crop variety and soil type specific. These effects were linked to shifts in soil carbon composition and prokaryotic communities that particularly increased Cd mobility in soil. In contrast, a long-term field experiment was conducted under milder future conditions, including a +0.55°C increase in mean annual temperature, a 10% increase in spring and autumn precipitation, and a 20% decrease in summer precipitation. These smaller changes had no significant effects on Fe, Zn, Cd, or As concentrations in wheat and barley grains. However, organic farming did buffer climate-induced yield losses in wheat under this scenario. Climate incubation experiments using present-day soils without prior climate adaptation generally captured the direction of future biogeochemical responses, supporting their validity. Yet, without climate adaptation, the extent and timing of these responses may be misestimated due to inherited geochemical and microbial traits. This thesis demonstrated that metal(loid) dynamics in agroecosystems, and their subsequent effects on crop nutritional quality and soil prokaryotic stability, are governed by complex interactions among soil, crop, and prokaryotic processes. These interactions can be intensified under more severe climate conditions, particularly for harmful elements like Cd and As. Agricultural management might play a dual role in this challenge. While intensive conventional farming with mineral fertilization increases metal(loid) stress on agroecosystems, organic approaches offer promising mitigation strategies. As coupled climate change and metal(loid) contamination increasingly transform global croplands, science-based approaches to managing soil–crop–prokaryote systems will be critical for securing food safety, soil fertility and agroecosystem sustainability. Thu, 25 Nov 2027 00:00:00 GMT http://hdl.handle.net/10900/180799 2027-11-25T00:00:00Z http://hdl.handle.net/10900/180788 7dSh – a Natural Sugar from Cyanobacteria as a Sustainable Herbicide Aries von Manteuffel, Nathan Matthias The use of herbicides over the last 80 years has been a constant driver of global food production. Specifically, the development of glyphosate-containing herbicides, most notably Roundup®, has significantly impacted global food security. Glyphosate is a selective inhibitor of the essential shikimate pathway in plants, bacteria, and fungi. With increasing critical research into the safety of glyphosate and the emergence of glyphosate-resistant weeds, the search for alternative herbicides has intensified in recent years. Since herbicides are essential to global food production and security, finding alternatives to glyphosate is of great importance. A promising candidate in this search is the bioactive sugar 7-deoxy-sedoheptulose (7dSh). 7dSh is naturally produced by Synechococcus elongatus and Streptomyces setonensis. It has been identified as an inhibitor of the shikimate pathway in plants and cyanobacteria, just like glyphosate. These findings have positioned 7dSh as a promising alternative to glyphosate. However, questions remain about additional working mechanisms and more economical and efficient methods of 7dSh production. In this work, Streptomyces setonensis was used to produce 7dSh in 20 L bioreactors, achieving concentrations of up to 1 g/l. A novel purification protocol was developed that yields 7dSh with high purity using cost-effective, scalable methods. The development of an economically scalable production of 7dSh ensures sufficient supply for future work and provides a basis for the development of potential industrial applications. A mutant in the highly sensitive strain Trichormus variabilis was found to show no sensitivity to 7dSh. Multi-sequence alignment revealed mutations in genes previously not linked to 7dSh activity. Although further research is needed, these findings open new avenues for investigating 7dShs' working mechanisms. Furthermore, it was shown that 7dSh must be phosphorylated after uptake to be bioactive. Work on chlorotic cells revealed that 7dSh is a potent inhibitor of both glycogen production and consumption. Furthermore, CO2 flux measurements showed that 7dSh inhibits CO2 fixation as early as 100 minutes after application. Lastly, 7dSh was shown to strongly influence glutamate pools in chlorotic and vegetative cells. These findings cannot be attributed to inhibition of the shikimate pathway and therefore must result from yet unknown working mechanisms. Based on these findings, this work suggests that 7dSh is not a selective inhibitor of the shikimate pathway alone, but rather a potent disruptor of central carbohydrate and nitrogen metabolism. Mon, 15 Jun 2026 00:00:00 GMT http://hdl.handle.net/10900/180788 2026-06-15T00:00:00Z http://hdl.handle.net/10900/180752 Genesis and Significance of Sulfide-Silicate Emulsions in Magmatic Sulfide Deposits Raisch, Dominic Sulfide-silicate emulsion textures represent complex intergrowth of two chemically and physically contrasting melts which preserve crucial information on sulfide melt mobility, redistribution, and exsolution in magmatic and metamorphic systems. This cumulative thesis investigates the chemical, physical and mineralogical processes governing sulfide-silicate emulsion across the orthomagmatic Ni-Cu-PGE deposits Nova-Bollinger, Savannah and Sora, as well as in the high-grade metamorphosed SEDEX-type Pb-Zn-Cu mineralisation at the Silberberg deposit. Combined petrographic, textural and mineral-chemical analysis were conducted to shed light on emulsion formation and to understand their role in the genesis of unique features associated with these textures. The results strengthen the hypothesis that emulsion textures can form via multiple pathways: (1) Physical mingling of a sulfide melt with an anatectic silicate melt, (2) liquid immiscibility during magma evolution and hybridisation, and (3) simultaneous anatexis of sulfide ore and silicate country rock and consequent mingling during high temperature metamorphism. Infiltration-driven emulsion formation is associated with a broad spectrum of semi-massive sulfide rocks prompting the development of a genesis-based terminology for all involved textures. The introduced terminology comprises infiltration and disaggregation textures and subdivides the emulsion texture into droplet and bicontinuous emulsions, as well as pegmatoidal pockets. These newly categorised textures reflect different stages of sulfide melt infiltration and carry direct implications for ore exploration. At the infiltration front of Nova-Bollinger, the close association of silicate megacrysts with sulfide-silicate emulsions gave insight inro their influence on silicate crystal nucleation, growth kinetics, and element partitioning within the two immiscible melt system. At Sora, mineral chemistry and field relationships indicate that hybridisation between the gabbro intrusion and an anatectic leucogranite triggered sulfide saturation, with emulsion textures preserving the composition of the sulfide-saturated parental melt. The occurrence of oxide-apatite-coated silicate droplets suggest the involvement of a third immiscible Fe-Ti-P melt, potentially acting as a geological emulsifier that enhanced emulsion stability by inhibiting coalescence. Comparable emulsion textures at Silberberg demonstrate that such structures are not restricted to primary magmatic systems but may also develop during high-grade metamorphism through sulfide anatexis. Their preservation, together with elevated concentrations of low-melting-point chalcophile elements within the sulfides, provides diagnostic evidence for simultaneous sulfide and silicate anatexis. Collectively, these findings establish sulfide-silicate emulsions as robust petrogenetic indicators of melt interaction, hybridisation, infiltration, and remobilisation processes across both magmatic and metamorphic environments, thereby refining current models of sulfide melt mobility and ore formation.; Die Dissertation ist gesperrt bis zum 24. April 2027 ! Sat, 24 Apr 2027 00:00:00 GMT http://hdl.handle.net/10900/180752 2027-04-24T00:00:00Z