It is now well established that Iron (Fe) is a limiting element in many regions of the open ocean. Our current understanding of the key processes which control iron distribution in the open ocean have been largely based on thermodynamic measurements performed under the assumption of equilibrium conditions. Using this equilibrium approach, researchers have been able to detect and quantify organi...

This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 38, Linking Waterfowl with Contaminant Speciation in Riparian Soils, implemented and funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S. Department of Energy (DOE). This project addressed EPA’s technical issue of Mobile Toxic Constituents – Water and...

The mineralization of 1.0 to 100 ng each of four complexing compounds-oxalate, citrate, nitrilotriacetate (NTA), and EDTA-per ml was tested in media prepared in accordance with equilibrium calculations by a computer program so that the H, Ca, Mg, Fe, or Al complex (chemical species) was predominant. Sewage microorganisms mineralized calcium citrate more rapidly than iron, aluminum, or hydrogen ...

In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates,...