This three-year award in support of U.S.-France collaborative research in environmental chemistry involves Brian Teppen, Paul M. Bertsch at the University of Georgia's Savannah River Ecology Laboratory and Armand Masion at the Universite d'Aix Marseille III. The objective of their research is the study of iron-silicate complexation mechanisms that are thought to result in ironstone formation in soils. They will study aqueous iron-silicate complex formation at the atomic scale and the semi-local scale and combine the results obtained from X-ray absorption and scattering experiments with dynamic molecular modeling. The US investigators bring to this collaboration expertise in molecular dynamics methods. This is complemented by French expertise in iron hydrolysis and by access to complementary synchrotron radiation instrumentation and facilities. The experiments will take place at the National Synchrotron Light Source at Brookhaven, New York and at LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique) at the University of Paris.
Ironstone formation occurs in tropical soils over time as heat and moisture deplete soils of organic matter and inorganic plant nutrients. The soils become enriched in aluminum and iron, the iron is redistributed, and as a result of erosion, ironstones form and are exposed at the soil surface, thereby limiting plant growth. This project will advance understanding of this process and how to optimally manage the chemistry of tropical soils .
