Higher plants acquire iron (Fe) from the rhizosphere through two strategies. Strategy II, employed by graminaceous plants, involves secretion of phytosiderophores (e.g. deoxymugineic acid in rice [Oryza sativa]) by roots to solubilize Fe(III) in soil. In addition to taking up Fe in the form of Fe(III)-phytosiderophore, rice also possesses the strategy I-like system that may absorb Fe(II) direct...

Dissolved Fe(II) in seawater is deemed an important micronutrient for microbial organisms, but its analysis is challenging due to its transient nature. We conducted a series of Fe(II) method comparison experiments, where spikes of 5 to 31 nM Fe(II) were added to manipulated seawaters with varying dissolved oxygen (37 to 156μM) concentrations. The observed Fe(II) concentrations from four analyti...

The chemical reduction of U(VI) by Fe(II) is a potentially important pathway for immobilization of uranium in subsurface environments. Although the presence of surfaces has been shown to catalyze the reaction between Fe(II) and U(VI) aqueous species, the mechanism(s) responsible for the enhanced reactivity remain ambiguous. To gain further insight into the U–Fe redox process at a complexing, no...

The redox chemistry of Fe in fog and cloudwater has been investigated at coastal and inland locations in the Los Angeles basin, in Bakersfield California, and in Delaware Bay. Samples were collected and analyzed for Fe (Fe(II), Fe(III), total Fe), sulfur (S(IV), S(VI)), organic ligands (formate, acetate, oxalate), total organic carbon (TOC), pH, major cations (sodium, calcium, magnesium, potass...

We examined the effects of organic carbon from oxygenic photosynthetic algal biomass on the redox cycling of Fe and S in an acid mine drainage (AMD)impacted system. Fe(III)-rich sediments from the field site with abundant algae contained fewer Fe(II) oxidizing bacteria and lower rates of Fe(II) oxidation compared to sediments that did not contain abundant algae. The addition of algal biomass to...

This thesis work is aimed at examining the oxygen atom mixing between common iron(III) oxides and Fe(II)aq solution during the sorption process. First, O labeled iron(III) minerals were used in batch sorption reactors to study the exchange of oxygen atom within the Fe(II)aq – iron(III) oxide system. Results showed a much lesser extent of oxygen mixing than reported Fe mixing from previous studi...

The chiral triplesalen ligand H6chand(RR) has been used to synthesize the chiral heptanuclear complexes [{(chand(RR))Mn(III)3}2{Fe(II)(CN)6}](ClO4)2 ((RR)[Mn(III)6Fe(II)](ClO4)2) and [{(chand(RR))Fe(III)3}2{Fe(II)(CN)6}](ClO4)2 ((RR)[Fe(III)6Fe(II)](ClO4)2), which have been characterized by single-crystal X-ray diffraction, mass spectrometry, elemental analysis, FT-IR, Mössbauer, and UV-vis spe...

We present near-infrared (observed frame) spectra of the high-redshift quasar S4 0636]68 at z\ 3.2, which was previously thought to be one of a group of ““ strong ÏÏ Fe II emitters [i.e., F(Fe II jj4434È 4684)/F(Hb)[ 1]. Our K-band spectrum clearly shows emission lines of Hb and [O III] jj4959, 5007, as well as optical Fe II emission. Our computed value of F(Fe II jj4434È4684)/F(Hb) ^ 0.8 for S...