RII Track-4: Microscale processes controlling speciation and transformation of phosphorus in soils

University Of Delaware, Newark DE

Investigators

Abstract

Non-technical Description Phosphorus (P) plays a pivotal role in the often-competing demands of food and safeguarding water quality. Chesapeake Bay is a national treasure and the nation's first estuary targeted by Congress for restoration. Improved understanding of the composition and the amount of P in the watershed leading to the Bay will enhance our ability to predict the potential risk of movement of P from forest, agricultural, and urban sources to the Bay waters. Scientific findings from this project will contribute to decades of work conducted by the Chesapeake Bay Program, US Geological Survey, and US Environmental Protection Agency in the Bay restoration plan. The PI and a graduate student from the University of Delaware (UD) will work with scientists at the California Institute of Technology to use a suite of sophisticated instrumentation that will determine the specific forms and concentrations of P in soils and waters. This work will greatly improve the current understanding of the complex processes that govern the environmental fate of P in the Chesapeake Bay watershed, and will enable the PI to employ techniques that are not available at the home institution. Technical Description Multi-scale interactions among forms of P and processes in soils and waters that vary across spatial and temporal scales call for a toolbox of advanced and innovative analytical methods capable of providing P structural information, which can connect the structure to chemical reactivity and transformation pathways. This research aims to identify the mechanisms of formation and transformation of different P pools in soils and its transport to open waters. It will utilize advanced analytical techniques, including spatially resolved electron microprobe analysis (EMPA), secondary ion mass spectrometry (nanoSIMS and magnetic SIMS), and laser ablation isotope mass spectrometer (LA-IRMS). In addition, a series of theoretical and experimental developments in light isotope systematics will be applied to identify and interpret microscale P speciation, physico-chemical association and in situ distribution of phosphate oxygen isotopes and their interrelationship in short- and long-term soil incubation as well as in soil chronosequence studies. This fellowship will maximize the PI's research productivity and leadership in several novel isotope techniques, and the knowledge and experience gained will catalyze new research fronts in the future. Findings from the project will be provided to the UD Cooperative Extension and other state and local agencies for their collective efforts to minimize the loss of nutrients from agricultural soils and to help achieve pollutant reduction goals.