On 09.07.24 Ms. Kühnhammer successfully defended her dissertation entitled "Uncovering the dynamics of tree root water uptake with in situ isotope techniques". This was the first doctoral thesis completed by the Isodrones group. The thesis was supervised at the IGÖ by Matthias Beyer.
In her dissertation, Ms. Kühnhammer developed an approach to measure stable water isotopes in soils and plants directly in the field. Previously, this required time-consuming sampling and laboratory analysis. Ms. Kühnhammer used the newly developed method to investigate water use strategies in a tropical dry forest in Costa Rica. In addition, Ms. Kühnhammer took part in a large-scale experiment at Biosphere 2 in Arizona, USA. There, the artificially created rainforest was dried out over several months and then re-watered “from below” (via the facility's drainage system). Ms. Kühnhammer discovered that all the large trees in Biosphere 2 have access to water resources deeper than 3m below the ground. However, the water absorbed from the depths was used differently by the different tree species. With her doctoral thesis, Ms. Kühnhammer has made an important contribution to the development of in situ isotope methods. Good luck for everything to come, dear Kathi!
On 11.04.2024, Charlotte Steinigeweg successfully defended her dissertation entitled "Conquering the foremost zone: Plant responses to environmental conditions in salt marsh pioneer zones". In her work, Charlotte investigated the establishment of plants in the pioneer zone of salt marshes and the effects on the ecosystem mediated by characteristic properties of these plants, as well as their response to certain ecosystem properties such as hydrodynamic conditions. With its results, the work contributes to a deeper process understanding of the plant-ecological and biogeomorphological interactions in salt marshes. In the joint project "Gute Küste Niedersachsen" - a graduate school of the TU Braunschweig, LU Hannover and the University of Oldenburg funded by the Volkswagen Foundation and the MWK Niedersachsen via VWvorab - this thesis was the first doctorate to be completed. Congratulations!
Julian Fricke successfully defended his dissertation paper titled "Surface complexation and reactive transport modeling: batch sorption and column experiments of Ni with quartz, K-feldspar, and muscovite" on 11/10/2023.
Leila Lazemi successfully defended her dissertation entitled "Spatio-temporal variation of particle number concentrations and size distributions across Germany using statistical analysis and modelling" on 11 October 2022. The thesis was supervised by Stephan Weber at the IGÖ.
On 20.05.2022 Agnes Straaten successfully defended her dissertation thesis entitled "Size-resolved particle number flux measurements in the urban boundary layer". Agnes collected a multi-year dataset of size-classified particle fluxes in Berlin using the micrometeorological eddy covariance method and evaluated it with respect to different research questions (e.g., anual variability, particle sources and sinks in the study area, influence of the COVID-19 lockdown on particle fluxes). The work was supervised at the IGÖ by Stephan Weber.
On Feb. 17, 2022, Sara Zaferani successfully defended her dissertation thesis entitled "Role of primary production for sequestration of natural and anthropogenic mercury in ocean sediments". The doctoral advisor is Prof. Harald Biester from the Environmental Geochemistry group.
Deep Joshi has successfully defended his dissertation "Characterization of Soil Hydraulic Properties for Modeling the Soil Water Dynamics at Different Spatiotemoral Scales". The content of his dissertation was to investigate the role of different parameterizations of soil hydraulic properties in describing soil water dynamics at different spatial and temporal scales. The doctoral supervisor is Prof. Wolfgang Durner from the Department of Soil Science and Soil Physics.
The content of this PhD thesis was the investigation of the effective hydraulic properties of stony soils from three perspectives: (i) experimental measurements, (ii) 3D numerical simulations and (iii) analytical methods. His doctoral supervisor is Prof. Wolfgang Durner.
On 28.01.2022 Lars Gerling successfully defended his dissertation entitled "Evaluation of microscale variation of urban ultrafine particle number concentrations and size distributions using a sectional aerosol model and statistical modelling approaches". The thesis was supervised at the IGÖ by Stephan Weber. Thanks also go to the external reviewer Prof. Dr. Tareq Hussein (University of Jordan, University of Helsinki).
Fabian Kalks successfully defended his dissertation on the topic "Dynamics of organic carbon in subsoils" on 20.07.2021. The thesis was prepared at the Institute for Agricultural Climate Protection of the Thünen Institute and supervised by Prof. Dr. Rolf Nieder from the Department of Soil Science and Soil Physics.
On 6 October 2020, Laura Grunwald successfully defended her dissertation within the framework of the disputation. Her dissertation "Urban cold-air paths - Properties and identification by modelling and geospatial analysis" dealt, among other things, with the development of methods for identifying urban cold-air paths by combining a two-dimensional, mathematical-physical cold-air runoff model (KLAM_21) and further analyses with the help of a geoinformation system. Furthermore, a machine learning method for the prediction of cold air pathways in a city was developed.
Diana Goertzen successfully defended her dissertation entitled "Diversity patterns of Central European Odonata in urban environments - a multi-scale perspective" on 20 August 2020. She dealt with the question of whether and under what circumstances dragonflies can achieve high species numbers in urban habitats and makes suggestions on how biodiversity in cities can be promoted in practice. Among other things, she was able to prove that the diversity of dragonflies in cities can be higher than in agricultural landscapes. The work was part of the DBU project Management of water bodies to promote biodiversity - a contribution to the implementation of the biodiversity strategy in cities and took place under the direction of apl. Prof. Dr. Frank Suhling.
Antonio J. Pérez Sánchez successfully defended his PhD thesis on "Response of ant assemblages to changing management practices in permanent grasslands of Central Germany" on 17 August 2020. The aim of his work was to understand the relationship between land use, environmental factors and ant communities (composition, species number and structure) on permanent grasslands in Central Germany in order to improve future conservation measures. His dissertation shows that the influence of grassland use on ants cannot be determined independently of local site characteristics (e.g. temperature and humidity). Thus, both local conditions and the regional context must be taken into account when investigating the relationship between ant communities and management in European grasslands. The work was carried out at the Thünen Institute for Biodiversity under the direction of Prof. Dr. Jens Dauber and in cooperation with the Department of Landscape Ecology & Environmental Systems Analysis. The work was funded by a research grant from the German Academic Exchange Service (DAAD). Congratulations!
Carluvy Baptista-Salazar, Lic., in Chemistry, successfully defended her dissertation on "Biogeochemical cycling of mercury in contaminated forested systems: Species, isotope ratios and fluxes" on 6 December 2018. The thesis was written under the supervision of Prof. Dr. Harald Biester as part of the project "The Role of Fluid Exchange in Earth and Environmental Systems", which was funded by the state of Lower Saxony as a sub-project of the GEOFluxes graduate school. Her dissertation shows that studies focusing on the transport dynamics of particulate Hg and Hg species can contribute to a better understanding of Hg cycles and transformations in the vicinity of former Hg mining sites. The combination of stable Hg isotopes with Hg solid phase speciation provided new insights into potentially different Hg isotope compositions associated with Hg species transformation processes, rather than relying solely on Hg fingerprint-based contamination source localisation. Congratulations!
Cora Vos successfully defended her dissertation on "Spatial variability and driving factors for soil organic carbon stocks, quality and saturation in agricultural soils of Germany" on 29 November 2018. She focused on the main driving factors for spatial variability as well as questions of the stability of different C fractions and the C storage potential of soils. She used extensive analysis results from the current soil condition survey for agriculture as a data basis. The work was carried out at the Thünen Institute for Agricultural Climate Protection under the supervision of PD Dr. Axel Don. At the TU Braunschweig, the work was supervised by Prof. Dr. Rolf Nieder. Congratulations!
Tobias Karl David Weber, M.Sc. in Geoecology, successfully defended his dissertation on "Characterizing hydraulic properties and net ecosystem exchange of an ombrotrophic peat bog by inverse modelling" on 4 April 2018. The thesis was written under the supervision of Prof. Dr. Wolfgang Durner as part of the project "From moisture state to gas exchange: Water and gas flux dynamics in peatlands as controlling factors for redox conditions and natural organic matter turnover", which was funded by the state of Lower Saxony as a sub-project of the GEOFluxes graduate school. Mr. Weber is now working as a postdoctoral researcher at the University of Hohenheim. Congratulations!
Anne-Kathrin Schneider, graduate geoecologist, successfully defended her dissertation on "Spatiotemporal distribution patterns of earthworms and their role in soil hydrological functioning" on 3 July 2018. As part of the DFG research group "Catchments as Organised Systems (CAOS)" (FOR 1598), she created distribution models for earthworms for a mesoscale catchment in Luxembourg and investigated and quantified the relationships between earthworm activity and the occurrence of macropore flow in the field. The work was started at the TU Munich under the supervision of Prof. Dr. Boris Schröder-Esselbach and finished here with the transfer to the TU Braunschweig. Congratulations!
Susan Marina Britz, graduate geoecologist, successfully defended her dissertation on "Europium sorption experiments with muscovite, orthoclase, and quartz: Modelling of surface complexation and reactive transport" on 6 April 2018. The thesis was written at the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) in the Site Selection Department (Repository Division) under the supervision of Dr Nosek as part of the "WEIMAR" project (further development of the smart-Kd concept for long-term safety analyses). At the TU Brauschweig, she was supervised by her doctoral supervisor Prof. Dr. Wolfgang Durner and Dr. Sascha C. Iden. Ms Britz continues to work at GRS as a postdoctoral researcher. Congratulations!
On July 11, 2017, Quentin Schorpp successfully defended his doctoral thesis on "Dynamics of below ground functional biodiversity in soils cropped with the perennial energy plant Silphium perfoliatum L.". For the first time, he investigated the influence of the perennial silphium (Silphium perfoliatum) on the structural and functional diversity of soil animals in the laboratory and in the field. The work was carried out at the Thünen Institute of Biodiversity under the direction of Prof. Dr. Stefan Schrader. At the TU Braunschweig, the work was supervised by Prof. Dr. Rolf Nieder. Dr. Schorpp works as a research assistant at the Julius Kühn Institute in Braunschweig. Congratulations!
Dr. Axel Don, geoecologist and deputy director of the Thünen Institute of Climate-Smart Agriculture, successfully completed the habilitation process in the Department of Civil and Environmental Engineering with his inaugural lecture on 2 November 2017 at the Technical University of Braunschweig. Through his habilitation thesis "Human impact on soil organic matter dynamics and stocks" as well as through courses and a habilitation lecture, he had previously demonstrated his special aptitude for independent research and teaching. The academic mentor for his habilitation was Prof. Dr. Rolf Nieder from the Institute of Geoecology. Congratulations!
The graduate geoecologist Viridiana Alcántara successfully defended her dissertation on "Long-term effects of soil organic matter burial on carbon sequestration" on May 31, 2017. The thesis was written as part of the "Humus burial" project, a cooperation project between the Thünen Institute under the direction of Dr. Axel Don and the Boku Department of the TU BS under the direction of Prof. Rolf Nieder. Ms. Alcántara now works at the FAO in Rome. We congratulate her!
Caroline Buchen successfully defended her dissertation on "The fate of nitrogen after grassland renewal and grassland conversion to maize cropping - An investigation of N2O processes and mineral N dynamics at the field scale" on January 27, 2017. To this end, she carried out multi-year field trials with grassland renewal and grassland conversion in the northern German Geest landscape. The work was carried out at the Thünen Institute of Climate-Smart Agriculture under the supervision of Prof. Dr. Heiner Flessa. At the TU Braunschweig, the work was supervised by Prof. Dr. Rolf Nieder. Dr. Buchen works as a research assistant at the ZALF in Müncheberg. Congratulations!
Jasmin Miltz defended her doctoral thesis on "Analyzing soil organic carbon using near infrared spectroscopy in the laboratory and in the field on-line" on May 9, 2016. Using near-infrared spectroscopy (NIRS), Ms. Miltz investigated a non-destructive, time-effective and cost-effective measurement technique for soil carbon in the laboratory and in the field.the work was carried out at the Thünen Institute of Climate-Smart Agriculture under the supervision of Prof. Dr. Heiner Flessa. At the TU Braunschweig the work was supervised by Prof. Dr. Rolf Nieder. Congratulations!
On April 12, 2016, biologist Maximilian Hofmeier successfully defended his dissertation on "Innovative nitrogen management and innovative technologies to improve agricultural production and protect the environment in Chinese intensive agriculture". The thesis was written in the BMBF project Innovative nitrogen management and innovative technologies to improve agricultural production and protect the environment in Chinese intensive agriculture. Here he supervised the field trials in Jiangsu Province and worked on the optimization of a growth model for the special conditions in the rice-wheat system. The thesis was supervised by Dr. Marco Roelcke and Prof. Rolf Nieder. Congratulations!
Benedikt Schrnagl, graduate geoecologist, successfully defended his dissertation on "Estimation of soil hydraulic parameters in the field by inverse modeling of soil water dynamics using Bayesian estimation" on 25.11.2015. The thesis was written at the Department of Soil Science and Soil Physics at the TU under the supervision of Prof. Dr. Durner and Dr. S. C. Iden as part of the project "Determination of hydraulic properties of substitute construction materials used in road construction". Mr. Scharnagl is working as a postdoctoral researcher at the UFZ Leipzig/Halle. Congratulations!
Dipl. Ing. Katja Walter successfully defended her dissertation on "Climate mitigation potential of annual and perennial bioenergy crops - Focusing on soil processes influencing the greenhouse gas balance" on 26.01.2015. The aim of the thesis was to compare different energy crops in terms of their contribution to greenhouse gas reduction. It was part of the BMBF joint project "BEST" (strengthening bioenergy regions), in which the sub-project "climate protection performance" was involved. The work was carried out under the supervision of Prof. Dr. Heiner Flessa. At the TU Braunschweig, Ms. Walter was supervised by Prof. Rolf Nieder. Congratulations!
Dipl.-Geographer Kerstin Ulrike Wolf successfully defended her dissertation on "Emission of NH3, N2O and CO2 following the application of differently treated digestates from biogas production" on July 31, 2014. The thesis was written as part of the DFG Research Training Group 1397 "Control of humus and nutrient balance in organic agriculture" under the supervision of Prof. Dr. Heiner Flessa. At the TU Braunschweig, Ms. Wolf was supervised by Prof. Rolf Nieder. Congratulations!
Lisa Heimann successfully defended her doctoral thesis "Optimization of nutrient and carbon management of agricultural land in the peri-urban region of Beijing with intensive animal husbandry" on 20.2.2013. In her thesis, Lisa Heimann investigated the nutrient situation in the peri-urban areas of Beijing with intensive animal husbandry as part of the Sino-German research project Recycling China. Her supervisor is Prof. Rolf Nieder, the project coordinator is Dr. Marco Roelcke. The work was carried out in cooperation with the China Agricultural University (CAU) in Beijing and the Agricultural University of Hebei in Baoding, PR China. Congratulations!
The environmental scientist Dipl. Christopher Poeplau successfully defended his dissertation on "The effect of land-use change on soil organic carbon stocks and quality in Europe" on March 19, 2013. The thesis was written at the Thünen Institute of Climate-Smart Agriculture as part of the "GHG-Europe" project, supervised by Prof. Rolf Nieder at the TU Brunschweig. Mr. Poeplau is now working as a habilitation candidate at the Thünen Institute of Climate-Smart Agriculture. Congratulations!
Henrike Schelle (after marriage: Henrike Mielenz) successfully defended her doctoral thesis "Identification of soil hydraulic properties on different scales using inverse modeling" on 12.02.2012. Henrike Schelle has been working as a research assistant at the Department of Soil Science and Soil Physics since April 2008 in the joint project INVEST - Inverse Modelling of Terrestrial Systems (Initiative and Networking Fund, Helmholtz Gesellschaft), investigating the possibilities and limitations of identifying system processes and system properties in saturated soil using inverse process modeling. The cumulative thesis ("with distinction") was supervised by Dr. Sascha C. Iden and Prof. Dr. Wolfgang Durner, with Prof. Dr. Hannes Flühler from ETH Zurich acting as second reviewer. Henrike is now moving to the CSIRO in Brisbane, Australia, as a Postdoctoral Fellow. Congratulations to her!
