Übergreifendes Ziel des Vorhabens ist es, die Rolle der Turbulenz für die Populationsdynamik des Phytoplanktons in marinen Systemen zu untersuchen. Im Zentrum des Projektes steht die zu überprüfende Hypothese, dass Ausprägung und Sukzession morphofunktionaler Lebensformen im Phytoplankton nicht ausschließlich Ausdruck unterschiedlicher Nährstoff-, Licht- und Temperaturregime im Milieu sind, sondern im entscheidenden Maße von direkten Turbulenzeffekten abhängen, die unmittelbar das Wachstum einzelner Arten regulieren und mit den anderen Steuerfaktoren interagieren. Im vorliegenden Projekt werden Auswirkungen unterschiedlicher kleinskaliger Turbulenzintensitäten auf die Phytoplanktonzuammensetzung im Feld, in Mesokosmen und Laborexperimenten untersucht und das Wachstum dominanter Arten auf seine Turbulenzsensitivität hin getestet. Eine praktische Herausforderung hierbei ist darüber hinaus die Beantwortung der Frage, wie zuverlässig und reproduzierbar Turbulenzintensitäten im experimentellen Modellsystemen erzeugt werden können.
Die Publikation gibt einen vertieften Einblick in die Ergebnisse der Treibhausgas-Projektionsdaten 2025, erläutert die Instrumentenbewertung und veröffentlicht die Daten für das Mit-Weiteren-Maßnahmen-Szenario. Die Projektionen zeigen eine kumulierte Unterschreitung der zulässigen Jahresemissionsgesamtmenge zwischen 2021 und 2030 mit geringen Unterschieden zwischen dem Mit-Maßnahmen- Szenario und dem Mit-Weiteren-Maßnahmen-Szenario. Die Darstellung der Ergebnisse erfolgt gemäß dem Zuschnitt der Sektoren des Bundes-Klimaschutzgesetzes (Energiewirtschaft, Industrie, Gebäude, Verkehr, Landwirtschaft, Landnutzung, LULUCF sowie Abfallwirtschaft und Sonstiges) sowie gemäß der EU-Klimaschutzverordnung (ESR). Darüber hinaus sind detaillierte Sensitivitätsanalysen Teil des Berichtes. Veröffentlicht in Treibhausgas-Projektionen für Deutschland.
Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic of the breakthrough curves in both experiments. The tests were interpreted using a single facture allowing for diffusion into an immobile matrix. We were able to interpet the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. We conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis proved that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will causetailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation. Methods and techniques used: Glaerkin-Finite-Elemente Method, Newton-Raphson, Levenberg-Marquardt, Preconditioned Conjugate Gradient Method, Maximum-Likelihood-Theorie, Confidence Ellipses.
We apply for a NanoSIMS 50L ion microprobe instrument for the analysis of soil biogeochemical properties. The specific features of the novel NanoSIMS 50L microprobe technology with the simultaneous analysis of up to seven ion species with high sensitivity and resolution make it an unprecedented tool for the analysis of biogeochemical processes and properties of soils and thereby will boost our ability to locate the association of elements/isotopes in soil structural components at the submicron scale, especially in combination with well-established labelling techniques. NanoSIMS will thus help to unravel the heterogeneous composition and three-dimensional architecture of submicron sized organo-mineral associations in soils. Our research will first focus on the simultaneous analysis of the spatial distribution of C, N, Si and Fe in organo-mineral associations and in a second step be applied to labelling studies: This unique combination provides one of the most promising approaches for exploring the C and N cycle of soils at a resolution not possible before. The NanoSIMS technique introduces new scales to combined multielement and isotope measurements at the submicron scale and thus will allow a major step forward in the understanding of soil formation, with significant implications for our concepts of the soil C and N cycle, soil structural stability, and the sorptive properties of the soil interface.
Wood samples from Douglas fir trees were taken using an increment borer. From each tree two opposing increment cores were taken at breast height. The sampled trees stood in an area of ~50x50 meters. Total ring width was measured and digitized. The resulting two radii measurements of each tree were visually synchronized and averaged to form a tree-ring series. Additionally, metadata were collected such as tree height, circumference and provenance (coastal, interior). The tree-ring data were used to investigate the resilience, resistance and recovery of the Douglas fir trees to severe drought events and to perform climate sensitivity analysis. This tree-ring dataset was part of a sampling campaign to assess the growth potential of Douglas fir trees until the year 2100. Annual tree growth variability until 2100 was modeled for Germany (including the river basins draining to Germany) with a spatial resolution of 12x12 km using regional climate projections ensemble.