ERC Starting Grant LAKE-SWITCH 2022-2027 (PI : Mathieu Dellinger)

LAKE-SWITCH ("Using lake sediments to reconstruct soil weathering trajectories over the Holocene") is a 5-years (2022-2027) research project funded by the European Research Council (ERC). It aims at answering the following question : How chemical weathering and soil formation have responded to the climatic and anthropogenic perturbations of the Holocene (the last 11.5 kyr) ?

Chemical weathering is a central process that shapes the Earth’s Critical Zone (CZ) and sets the pace for nutrient delivery to soils and ecosystems. How chemical weathering changes over hundreds to thousands of years remains poorly known. This limits our understanding of how long-lasting human-climate-ecosystem interactions have impacted soil trajectories during the Holocene. Because of this unknown, we cannot assess how rates of soil formation and weathering will respond to future climate and land-use changes.

Two key questions remain : to what extent chemical weathering fluxes vary over 100 to 10 000 year timescales ? How climatic and anthropic drivers impacted soil weathering trajectories during the Holocene ?

The LAKE-SWITCH project will tackle these fundamentals questions by using a combination of : i) state-of-the-art isotope geochemistry tracers : lithium (Li) and strontium (Sr) isotopes, ii) well-characterized lake sediment records, iii) a source-to-sink calibration methodology and iv) an original modelling approach.