- Transformation of micropollutants at the water-sediment interface, in agricultural soils, in urban setting and on the catchment scale with stable isotope fractionation (compound-specific isotope analysis)
- Degradation of industrial (chloroethenes, dichloromethane) in aquifers with stable isotope fractionation (compound-specific isotope analysis)
Understanding the transport and transformation of pollutants from toxic and diffuse sources represents a major challenge in the 21st century, and have become of utmost importance for the preservation of soil and water resources. A significant fraction of industrial or agricultural pollutants used in urban or agricultural areas is mobilised from their sources and transported overland via runoff in freely dissolved form, and in less bioavailable colloidal or organic matter-bound forms. Pollutants also infiltrate into soil and sediments, and eventually reach the aquifer. Surface and sub-surface pollutant fluxes may be intercepted and transformed in transitional reactive zones of the landscape, such as wetlands or ground-surface water interfaces, before they reach other ecosystems. Reactive zones are ‘biogeochemical hotspots’, bearing dynamic interfaces between water, soil/sediment and microorganisms, and develop dynamic combinations of electron acceptors and donors reflecting microbial diversity and biogeochemical activity.
In this context, the fundamental questions that bother me are : what is the hydrological and biogeochemical functioning of these ‘hotspots’ with respects to pollutant transport and microbial transformation ? What are the taxonomic and functional diversity, physiology, and metabolism of microorganisms involved in pollutant transformation ? How do microorganisms respond to the pollution regime and hydro-biogeochemical fluctuations, and influence key ecosystem services (e.g. water quality improvement, flood abatement, biodiversity) ? My research principally revolves around the scientific underpinning of microbial processes in polluted agricultural systems, aquifers and wetland systems.