Hosted by: Ignace Jarrige

Dissolved soil organic matter (SOM) hinders the crystal growth of Fe and Mn oxides but promotes the formation of metal-OM complexes. The strength of the interactions between SOM and the Fe(O,OH)6-octahedra depends, besides pH and ionic strength, on the available functional groups. We investigate the formation of oxides under alternating redox conditions in the presence of two isotopically labelled organic model substances: vanillin (lignin component with a reactive phenol group) and alanine (amino acid with a carboxyl and an amino group). Combining XRF, µXANES and µXRD at 5-ID will allow to identify Fe and Mn oxides, describe their crystallinity and estimate the importance of organic forms of Fe and Mn. Later, we will study the spatial distribution of vanillin and alanine across mineral surfaces by NanoSIMS.