Post by Steffen A. Schweizer

Several members of our research group at the Chair of Soil Science traveled to Vienna to participate in the #EGU26 General Assembly. We contributed to this year’s program with presentations on mechanisms regulating soil carbon dynamics across scales, from microscale interactions between minerals, microbes, and organic matter to broader implications of carbon dioxide removal strategies in terrestrial ecosystems. ⚗️ Haotian Wu presented findings from her PhD on how soil pore sizes and mineral surfaces regulate microbial activity and soil organic carbon cycling. Using model microcosms with mineral-coated pore networks, she tracked carbon mineralization and microbial carbon use efficiency across pore size classes. Her results show that mineral surfaces and pore architecture shape microbial access to organic matter, influencing carbon degradation and persistence in soils. The work is part of a French-German collaboration with Maëlle Maestrali and other amazing colleagues. 🔬 Sidra Ahmad presented a poster on mapping carbon compounds relevant to soil energy cycling at the aggregate scale. Using DESI-MSI, she and Lieby Zborovsky identified localized hotspots in manure-treated soils during incubation, indicating past microbial activity and necromass accumulation. This advancing imaging approach helps visualize the spatial organization of organic compounds and understand how microscale heterogeneity governs soil carbon and energy cycling. The work is part of the SoilSystems SPP 2322. 🌍 Maria Rivera, a Fulbright PhD Research Fellow from Cornell University, addressed uncertainties around enhanced rock weathering as a CO₂ removal strategy. Through a one-year incubation experiment across diverse soils, her research examines effects on inorganic and organic carbon pools, improving predictions of carbon removal potential and informing targeted application in different soil systems. 🧩 Steffen Schweizer presented research from Yahan Hu’s PhD on the microscale organization of soil organic matter. Using NanoSIMS data, the study showed that organic matter patches contain consistent µm-sized carbon- and nitrogen-rich subunits, providing new insights into spatial heterogeneity and its role in soil carbon storage. This work was funded by BMFTR. Attending #EGU26 provided a valuable opportunity to share our research, engage with the global soil science community, and foster new collaborations. TUM School of Life Sciences European Geosciences Union (EGU) EGU - Soil System Sciences (SSS) Division