Hannah Marchant

Hannah Marchant is a Researcher in the Department of Biogeochemistry at the Max Planck Institute for Marine Microbiology, Bremen. Her work focuses on microbial ecology and biogeochemical processes in coastal sediments, particularly the interplay between microbial communities and nitrogen cycling under environmental pressures such as climate change and eutrophication. She investigates permeable sediment systems, emphasizing how advection, porewater dynamics, and microscale environments drive nutrient transformations like denitrification and nitrogen fixation.

Her research integrates field studies, lab experiments, and molecular techniques to understand microbial responses to dynamic redox conditions, anthropogenic impacts, and extreme environments. Key topics include organic nitrogen utilization by nitrifiers, the role of sand grain microenvironments in nitrogen loss, and the fate of ancient carbon released from permafrost. Collaborations include studies on symbiotic relationships between marine organisms and microbes, such as diatoms and rhizobia.

Recent work highlights the importance of microbial community specialization in controlling greenhouse gas emissions (e.g., N₂O) and the degradation of organic matter in Arctic and coastal zones. Her findings contribute to predicting ecosystem resilience under climate change and improving models of global element cycles.