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Accueil > Équipes > Biogéochimie ISotopique et Expérimentale - BISE

Isotope and Experimental Biogeochemistry - BISE

Responsables : G. Imfeld & D. Lemarchand

publié le , mis à jour le

Isotope and Experimental Biogeochemistry

The group works on mechanisms and forecasts relative to transfer processes and matter transformations in the Critical Zone.
The latter refers to the outermost thin layer of the planet Earth housing physical and chemical interactions between air, water, organisms, and rocks. This interface between bedrock, landscape, and atmosphere, is essential for cycles of water, nutrients, and contaminants. It is also critical because it hosts most of human activities. The team develops biogeochemical and isotopic approaches and applies them at the lab and over natural sites at the scale of water catchment systems.

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Study of natural sites

The team is involved in a set of studies especially relying upon isotopic approaches to determine :

• The history of formation and evolution of alteration profiles (U-Th-Ra),
• Exchanges and transfers between soil and vegetation (Li, B, Ca, Sr, Cu, Zn ...),
• The transformation of micro-pollutants monitored via compound-specific isotope analysis (CSIA).

Mechanisms and rates of mineral alteration, but also signatures of transformation mechanisms at the interfaces between water, soil, and organisms can thus be identified.
These studies compare results stemming from laboratory experiments with observations from dedicated experimental catchments, such as the Strengbach OHGE (forestry) and Rouffach (vineyard).

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Experimental studies

The contributions comprise various topics such as :

• describing mechanisms and formulating kinetic laws of water-mineral / soil-organism interactions,
• developing tracers of these interactions and transformation processes,
• setting up experimental approaches in the lab and in the field, for simplified or close to natural complexity systems. As an example, new insights become available on the relationship between reaction processes at the mineral scale and dissolution rates evidenced at the macroscopic scale.