The Florida Everglades is historically limited in phosphorus; however, runoff from the Everglades Agricultural Area has resulted in a gradient in phosphorus and sulfate concentrations running into the interior of the northern Everglades. A detailed understanding of the impacts of P- and S-enrichment on methanogenesis is therefore critical to our understand
Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Though it is widely known that radiation can adversely affect the properties of these materials, the nature of the damage to the crystallographic structure is not well known due to the lack of appropriate characterization techniques. In this work, we use crystallographic structural refinement (i.e., the Rietveld method) to quantify the type and concentration of point defects in lead zirconate titanate (PZT) exposed to a 1 MeV equivalent neutron fluence of 1.7×10^15 neutrons/cm^2. The results are compared to a control group aged for an equal time. PZT based materials of the following three compositions are investigated: (1) undoped, (2) Fe-doped, and (3) Nb-doped PZT. Laboratory X-Ray diffraction is used to determine the initial phase purity of the materials. After irradiation, neutron diffraction from the SMARTS diffractometer at the Los Alamos Neutron Science Center (LANSCE) is used to analyze the crystal structures of each sample using Rietveld refinements.
ing of greenhouse gas emissions. On a global basis, most methane is produced directly from acetate via acetoclastic pathways. Preliminary data indicated that U3 follows this paradigm; however, most methane from F1 is produced via hydrogenotrophic methanogensis, an alternative pathway. This indicates that nutrient enrichment in Water Conservation Area 2-A is responsible for shifting that fundamental pathway. We hypothesize that syntrophic acetate oxidation (SAO) is responsible for much of the hydrogen driving methanogenesis in F1. Our objective is to isolate syntrophic acetate oxidizers from the soil along the nutrient gradient in WCA 2-A, including a site previously exposed to high levels of nutrients (Impacted - F1), a transition site (Transition - F4), and a site not impacted by nutrient additions (Unimpacted - U3). In the current study, we will identify active acetate SAO by using a combined approach that includes isolation of target group organisms and DNA-stable isotope probing with 13C-labled and unlabeled acetate. The Everglades soils will be incubated anaerobically at both 23 and 37 degrees Celsius with either 13C-labled or unlabeled acetate as the sole carbon and energy source. The results obtained from this study will provide a better understanding of how SAOs control methane production along with nutrient gradients in the Everglades.