Reconstructing Si cycling in transition zones during the Holocene using terrestrial and aquatic records

The primary aim of this PhD project is to better understand the interplay of Si sources and sinks in continental ecosystems. Terrestrial Si fluxes from soils to rivers and lakes are the most important Si source on geologically short timescales (decades-centuries). Potentially influenced by natural and anthropogenic vegetation changes as well as climate shifts, these fluxes are yet poorly constrained. By measuring Si isotopes in diatom frustules we have a tool to disentangle different processes potentially influencing the Si availability (Si source) and Si uptake (diatom production) in an ecosystem. Coastal zones and lakes are suitable archives recording changes in terrestrial Si cycling but also climate and vegetation shifts, allowing multi-proxy studies.