“Biogeochemistry and Transport of Iron at the Soil Aggregate and Horizon Scale”
By Celine Pallud (Associate Professor, Environmental Science, Policy & Management, Univ. of California-Berkeley
Abstract: Understanding and predicting the fate and transport of nutrients and contaminants in natural systems is a continuing challenge in soil science. Biogeochemical processes controlling elemental cycling in soils are heterogeneously distributed owing to chemical conditions dictated by the local mineralogical and physical environment. Consequently, the fate of chemicals in soils is dependent on the convoluted coupling of biological, chemical and hydrological processes that vary spatially from the micro- to the macroscale. In structured soils, the aggregate scale (mm to cm) is of particular interest and chemical species distribution can be strongly localized due to mass-transfer limitations and redox gradients within soil aggregates. Iron (hydr)oxides are ubiquitous in soils, playing a dominant role in the geochemistry of surface and subsurface environments. This presentation will discuss the use of flow-through reactors of increasing complexity, to study the coupling of physical, and (bio)geochemical processes affecting iron cycling in soils in order to fill the gap between understanding of well mixed batch systems and observations on very complex natural subsurface systems.
*Made available by the generosity of Leo M. Walsh and the Leo M. Walsh Distinguished Lectures in Soil Science Fund*