SoSe 2025
May 14, 2025 – Dr. Maximilian Dröllner
University of Göttingen, Dept. of Sedimentology and Environmental Geology
To see the world in a grain of sand
Sediments are an archive of Earth's evolution: from an anoxic Hadean world to a habitable planet with an oxygenated atmosphere. Yet, reading this archive is anything but straightforward. Single-grain sedimentary provenance analysis, through the lens of accessory detrital minerals, offers a way to address the intrinsically fragmentary nature of the sedimentary record. The first part of the talk showcases examples of integrated in situ analytical techniques (e.g., U–Pb–He, Lu–Hf, trace elements) used to reconstruct complex grain histories and unravel sedimentary recycling. The second part presents ongoing work that extends conventional provenance approaches by incorporating a novel tool: cosmogenic krypton in detrital zircon. This method combines the best of both worlds, providing a previously unavailable window into the surface history of accessory mineral grains. Preliminary results reveal an apparent relationship between zircon surface exposure history and sediment composition, emphasizing the potential of this approach for developing a more complete understanding of ancient sedimentary systems.
June 11, 2025 – Prof. Dr. Eberhard Gischler
Goethe University Frankfurt
A 5700-year storm and climate archive at annual resolution: the sunken cave of the Blue Hole in Belize
Predicting the frequency of tropical cyclones is hampered by insufficient knowledge of their natural variability in the past. A 30-meter-long sediment core from the Great Blue Hole, a flooded karst cave off the coast of Belize, provides the longest available continuous and annually resolved archive of storm frequency. This dataset extends our understanding from the instrumental record (73 years), historical documentation (173 years) and paleotempestological record (2000 years) to the last 5700 years. A total of 694 event layers were identified. They show a clear regional trend of increasing storm activity in the southwestern Caribbean following an orbitally induced shift of the Intertropical Convergence Zone. The superimposed short-term variations match Holocene climate intervals and are caused by solar radiation-driven sea surface temperature anomalies. An extrapolation for the 21st century indicates an unprecedented increase in storm frequency due to Industrial-Age warming.
June 18, 2025 – Dr. Tim Vietor
Nationale Genossenschaft für die Lagerung radioaktiver Abfälle [NAGRA], CH
1 Mio years of safety for radioactive waste - is geological disposal a reliable option?
For a deep geological repository of nuclear waste radiological safety has to be assessed over geological time. Is this a feasible task? In Switzerland, Nagra - the organization responsible for the site selection - has just submitted the documentation that discusses radiological safety over 1 Million years. These reports are based on state-of-the-art geoscience and a detailed reconstruction of the geological history of Northern Switzerland. Tim Vietor, Head of Repository Safety at Nagra and former student of Geology here in Göttingen will present the data that lead towards the most suitable site in Switzerland and indicates that clay formations are able to isolate radioactive waste over millions of years.
June 25, 2025 – PD Dr. Jacek Raddatz
GEOMAR Helmholtz Centre for Ocean Research Kiel
Environmental control on Quaternary cold-water coral ecosystems
Unlike warm-water coral reefs, which thrive in near-surface waters, cold-water corals (CWC) and their reefs occur in deep, cold and nutrient-rich waters in almost all of the world's oceans. After more than two decades of research, the CWC community is struggling to explain the occurrence and distribution of these unique reefs in the deep sea, especially fossil CWC reefs. This talk will present the methods used to constrain past environmental boundary conditions of CWC growth as well as the most important findings and contradictions in CWC research.
July 2, 2025 – Prof. Dr. Jakob Santner
Institute of Plant Nutrition, Justus Liebig University Giessen
Silicon fertilization for improving the fertilizer phosphorus use efficiency?
Silicon, a non-essential, but beneficial element for plants, is being discussed as a means to improve the resilience and stress tolerance of crops. Among its known effects is the improvement of phosphorus uptake from soil by crop plants. While this effect has been demonstrated in several experimental studies, and is being put forward as an argument for applying Si in arable farming, a comprehensive assessment of the benefit of Si fertilization for crop P uptake is still lacking. We compiled existing Si-fertilization experiments that evaluated its effect on crop P uptake and conducted a meta-analysis. Although only relatively few studies are available, they consistently show an improvement of crop P uptake, resulting in improved fertilizer phosphorus use efficiency. Given the globally limited rock phosphorus resource, the detrimental environmental effects of high P fertilization, and potential additional beneficial Si effects on crop performance, combined Si-P application is an interesting fertilization strategy worth investigating further.
July 9, 2025 – Dr. Christine Liang
Helmholtz Centre for Environmental Research, Leipzig
Extreme Citizen Science in the Arctic: Building resilience in marine pollution control with Arctic communities
The Arctic experiences disproportional environmental degradation and risks to communities due to climate change and pollution. The ICEBERG project (Innovative Community Engagement for Building Effective Resilience and Arctic Ocean Pollution-Control Governance in the Context of Climate Change), funded by the European Union, is a multidisciplinary effort that investigates the types, sources, distributions, and impacts of pollution on ecosystems and coastal communities across the European Arctic. This talk explores how ICEBERG integrates the principles of extreme citizen science throughout different stages of development, project disciplines, and field campaigns. The talk will highlight innovative strategies employed to empower citizens, foster collaboration, and ensure that diverse perspectives shape the project's outcomes.