Temporal variability (role of the catchment and climate)

This research component investigates lake carbon cycling at global and long-term scales in the context of global environmental change. It aims to quantify organic and inorganic carbon fluxes entering, leaving, and being stored in lakes, with a particular focus on sedimentary carbon sequestration and greenhouse gas emissions. By combining long-term observations, large-scale spatial datasets, biogeochemical modelling, paleolimnological approaches, and experimental studies, this theme seeks to identify the environmental drivers controlling lake carbon budgets at regional to global scales.

Paleolimnological approaches provide insights into long-term trajectories of lake carbon dynamics and the influence of past climate variability and anthropogenic pressures on carbon sequestration and emissions. Experimental approaches further investigate the role of key processes controlling carbon and nutrient transformations, particularly in sediment–water interfaces.

A major research focus concerns the biogeochemical consequences of water-level fluctuations in reservoir drawdown zones. Through controlled sediment incubations, the effects of drying–rewetting cycles on carbon, nitrogen, and phosphorus dynamics are assessed under varying environmental conditions (hydrodynamics, temperature, oxygen availability, and duration/frequency of exposure). These processes are integrated into mechanistic models (e.g., GLM–AED) to predict the impacts of reservoir management practices on biogeochemical functioning and greenhouse gas dynamics. The approach will also be applied to sediment cores from high-altitude lakes to better understand long-term carbon and nutrient cycling in mountain aquatic ecosystems.