Forests rely on decomposition to function: dead leaves and wood need to be broken down so nutrients can be recycled back into the soil. This process is carried out by soil animals (such as mites and springtails) and fungi, which together break down plant material and interact with each other.
Human activities, especially agriculture, release large amounts of nitrogen into the air, which settles into the environment over time and accumulates there. While nitrogen occurs naturally, too much disrupts soil chemistry and affects the organisms that live there.
This thesis investigates how nitrogen pollution affects decomposition in oak forests, focusing on the soil animals and fungi responsible for breaking down leaf litter. Using feeding experiments, litter decomposition trials, and DNA analysis of fungal communities, the research shows that native oak forests are affected more than expected: microarthropod and fungal communities are missing important species which are crucial for breaking down complex organic matter. Without these species present, leaf litter cannot be decomposed.
The findings help explain why some forests are losing their ability to recycle nutrients efficiently and point to consequences for forest health under continued nitrogen pollution.
Marie-Charlott studied Biology at the University of Cologne (BSc) and Ruhr-Universität Bochum (MSc), where her research spanned across multiple disciplines. For her Bachelor thesis, she focused on invasive fish in the river rhine. During her master, she worked abroad in Italy on nature conservation. Marie-Charlott wrote her master thesis about predator-prey population modelling in MATLAB. Her PhD research focused on how nitrogen pollution affects decomposition processes in oak forests, based at the Veluwe. Her work combined a feeding experiment, litter decomposition trials, DNA-based analysis of fungal communities, and network analysis of how fungi and soil animals interact.
Alongside her research, Marie-Charlott was active in science communication and outreach, producing a podcast and giving public presentations for high school and university students. She also served on two academic committees supporting PhD students. She speaks German, English, Dutch, and Italian, and considers herself an allrounder who enjoys working across disciplines and contexts.