https://ediss.sub.uni-hamburg.de:443/handle/ediss/2 2026-04-25T00:24:20Z 2026-04-25T00:24:20Z Maslouski, Mikita https://ediss.sub.uni-hamburg.de:443/handle/ediss/12352 2026-04-24T23:34:39Z 2026-04-24T11:19:15Z

Title: Estimating the impact of soil-vegetation feedbacks on the efficiency of combined pyrogenic carbon capture and enhanced weathering Authors: Maslouski, Mikita Abstract: This cumulative dissertation, investigates how soil-vegetation feedbacks influence the carbon dioxide removal (CDR) efficiency of two land-based strategies: Pyrogenic Carbon Capture and Storage (PyCCS) through biochar application, and Enhanced Rock Weathering (ERW) through silicate rock powder. The work was conducted within the PyMiCCS project, funded by Germany's BMFTR CDRterra program, and its central contribution is the development and application of the LiBry-DETECT Layer Scheme (LiDELS), a one-dimensional process-based ecosystem model that couples soil water and heat transport, microbial respiration, vegetation carbon assimilation, soil CO2 dynamics, and a simplified silicate weathering module. The introduction frames the scientific motivation: anthropogenic climate change requires not only sharp emission reductions but also large-scale CDR on the order of 7-9 GtCO2 per year by mid-century. Biochar and silicate rock powder are identified as particularly promising options due to their agricultural co-benefits and compatibility with existing land management practices. A critical gap in existing modeling tools is identified -- no framework simultaneously represents soil physics, microbial dynamics, vegetation productivity, and mineral dissolution -- and this gap provides the primary motivation for developing LiDELS. The first study, presented in Chapter 2 and published in Environmental Research Letters, introduces LiDELSv1 and applies it to a sandy soil under Hamburg's climate using a 40-year ERA5 dataset. Three biochar types produced at different temperatures and from different feedstocks are simulated at a 1% w/w application rate. The model shows that biochar consistently increases soil water retention in the application layer by around 35%, which in turn enhances evapotranspiration and boosts net primary production by approximately 6%. Soil CO2 concentrations rise by about 21% due to increased microbial activity and reduced gas diffusivity, yet surface CO2 emissions remain statistically unchanged across treatments. The net result is a modest accumulation of soil organic carbon of roughly 20 gC m-2 yr-1. A key insight from this chapter is that vegetation plays a central mediating role: the increased plant water uptake prevents the waterlogging that would otherwise stimulate microbial respiration and undermine the carbon sequestration benefit. The second study, presented in Chapter 3 and also published in Environmental Research Letters, extends the framework to LiDELSv2 by incorporating a soil evaporation module, a biochar degradation function calibrated to oak wood biochar produced at 650°C, and a calcium leaching module representing silicate weathering. The model is calibrated against data from a lysimeter experiment at Hochschule Geisenheim University and then used to simulate 1,000-year carbon dynamics under four amendment scenarios: sole wood biochar (WB), sole basanite rock powder (RP), their co-application, and a co-pyrolyzed rock-enhanced biochar (RE-biochar). Wood biochar alone produces the strongest and most persistent CDR signal, increasing non-biochar soil organic carbon by 52% and maintaining a net CO2 sink of approximately 200 gC ha-1 yr-1 per ton of applied biochar over the full millennium. Rock powder alone reduces soil organic carbon by 7% through hydrological changes that lower plant-available water, and its CDR contribution via enhanced calcium leaching is negligible at around 3 g CO2 ha-1 yr-1. Co-application and RE-biochar produce intermediate outcomes that clearly exceed rock powder alone but fall short of the performance of biochar alone, suggesting that adding rock powder to a biochar system dilutes rather than enhances its long-term CDR potential under the modeled conditions. Changes in net primary production and ecosystem respiration across all treatments remain small relative to natural ecosystem variability, underscoring that long-term CDR in this system is driven primarily by the chemical stability of pyrogenic carbon rather than by sustained shifts in biological fluxes. The concluding chapter synthesizes these findings and reflects on the broader implications. Soil hydrology emerges as the dominant control on amendment outcomes in coarse-textured, water-limited soils, with vegetation feedbacks amplifying CDR during the early post-application decades and the resulting shifts in soil carbon trajectories persisting over millennial timescales. The chapter also discusses the position of LiDELS relative to existing tools: it occupies a useful intermediate niche between detailed vadose-zone models like HYDRUS, which lack carbon cycle integration, and large-scale crop and carbon models like CENTURY or APSIM, which lack explicit soil physics and weathering pathways. Important limitations are acknowledged, including the absence of nutrient cycling, simplified geochemistry, no representation of agricultural management, and no accounting for non-CO2 greenhouse gas emissions. Future development priorities include integrating nitrogen and phosphorus cycles, incorporating surface albedo effects, expanding the weathering module to include multiple base cations, and upscaling LiDELS to a global framework using SoilGrids soil data and CMIP6 climate scenarios to identify regional CDR hotspots and inform carbon market measurement, reporting, and verification frameworks.

2026-04-24T11:19:15Z Amirzada, Daniela https://ediss.sub.uni-hamburg.de:443/handle/ediss/12354 2026-04-23T23:33:54Z 2026-04-23T13:36:40Z

Title: Expression von StAR in menschlichen Tumoren und Normalgeweben: Eine Tissue-Microarray-Studie an 19.202 Tumoren Authors: Amirzada, Daniela Abstract: Das Protein StAR (Steroidogenic Acute Regulatory) ist ein mitochondriales Transportprotein, das eine entscheidende Rolle bei der Regulierung der Steroidhormonproduktion spielt. Da seine Expression auf wenige normale Gewebe beschränkt ist, wurde die immunhistochemische Analyse von StAR als diagnostisch nützlich vorgeschlagen. Um den diagnostischen und prognostischen Nutzen der StAR-Expressionsanalyse umfassend zu bewerten, wurde ein Gewebe-Mikroarray mit 19 202 Proben von 152 verschiedenen Tumortypen und Untertypen und 608 Proben von 76 verschiedenen normalen Gewebetypen immunhistochemisch analysiert. Eine StAR-Immunfärbung trat in 198 (1,2 %) der 17 135 analysierbaren Tumoren auf. Eine StAR-Expression wurde in 27 von 152 Tumorkategorien beobachtet, von denen 9 mindestens einen stark positiven Fall enthielten. Die höchste Rate an StAR-Positivität wurde bei Leydig-Zell-Tumoren des Hodens und des Eierstocks (100%), Steroidzell-Tumoren des Eierstocks (100%), Nebennierenrindenkarzinomen (93%) und Adenomen (87%), Sertoli-Leydig-Zell- Tumoren (67%) und Granulosazell-Tumoren des Eierstocks (56%) sowie bei Seminomen (7%) festgestellt. 19 andere Tumorentitäten zeigten eine - meist schwache - StAR-Positivität in weniger als 6% der Fälle. Ein Vergleich mit bereits vorhandenen Melan-A-Daten ergab, dass StAR häufiger bei adrenokortikalen Neoplasmen und bei Leydig-Zell-Tumoren positiv war, während StAR (aber nicht Melan-A) bei Sertoli-Zell-Tumoren negativ war. Zusammenfassend bieten unsere Daten einen umfassenden Überblick über die Muster der StAR-Immunfärbung in menschlichen Tumoren und legen einen diagnostischen Nutzen der StAR- Immunhistochemie zur Unterstützung der Diagnose von Leydig-Zell-Tumoren oder von normalem oder neoplastischem Nebennierenrindengewebe nahe.

2026-04-23T13:36:40Z Börngen, Marlen https://ediss.sub.uni-hamburg.de:443/handle/ediss/12345 2026-04-23T23:33:44Z 2026-04-23T13:29:50Z

Title: Educational Approaches in Conservation between Europe and North Africa: A Comparative Study of Teaching Methods and Cultural Perspectives Authors: Börngen, Marlen

2026-04-23T13:29:50Z Paech, Andreas https://ediss.sub.uni-hamburg.de:443/handle/ediss/12347 2026-04-23T23:30:46Z 2026-04-23T12:48:03Z

Title: Agile IT-Personalentwicklung - Eine Grounded Theory für Dynamisches Matching zum Management von IT-Professionals in der Adaptionsphase Authors: Paech, Andreas Abstract: Die Dissertation richtet sich an IT- und HR-Manager:innen, die IT-Fachkräfte in agilen Organisationen wirksam führen, entwickeln und langfristig binden wollen. Im Mittelpunkt steht die Frage, wie Personalmanagement und IT-Projektsteuerung so verzahnt werden können, dass Skill-Gaps frühzeitig erkannt, Fehlanpassungen vermieden und Entwicklungsprozesse kontinuierlich gesteuert werden. Theoretisch verankert ist die Arbeit im Human Capital Management sowie dem Dynamic Matching Lifecycle Model (DMLM), die integrativ auf den IT-Kontext angewendet werden. Auf dieser Grundlage liefert die Arbeit ein praxisorientiertes Vorgehensmodell, das agile Sprintzyklen systematisch mit personalwirtschaftlichen Instrumenten (Kompetenzmanagement, Personalentwicklung, Retrospektiven) verbindet. Die Ergebnisse adressieren das strukturelle Trilemma aus HR-/IT-Alignment, Agilität und der hohen Erosionsrate von IT-Wissen und bieten konkrete Handlungsempfehlungen für ein nachhaltiges Management von IT-Professionals.

2026-04-23T12:48:03Z