Influence of Uranyl Speciation and Iron Oxides on Uranium Biogeochemical Redox Reactions

Pore-scale characterization of biogeochemical controls on iron and uranium speciation under flow conditions.

Etched silicon microfluidic pore network models (micromodels) with controlled chemical and redox gradients, mineralogy, and microbiology under continuous flow conditions are used for the incremental development of complex microenvironments that simulate subsurface conditions. We demonstrate the colonization of micromodel pore spaces by an anaerobic Fe(III)-reducing bacterial species (Geobacter ...

Biogeochemical changes induced by uranyl nitrate in a uranium waste pile

the influence of social and cultural capital on efl students critical thinking skills

the major aim of this study was to investigate the relationship between social and cultural capital and efl students’ critical thinking skills. this study takes this relationship in to account to see if people with different sociocultural status are different regarding their critical thinking skills. to this end, 160 university students majoring in english language and literature, english trans...

Influence of Mn oxides on the reduction of uranium(VI) by the metal-reducing bacteriumShewanella putrefaciens

The potential for Mn oxides to modify the biogeochemical behavior of U during reduction by the subsurface bacterium Shewanella putrefaciens strain CN32 was investigated using synthetic Mn(III/IV) oxides (pyrolusite [ -MnO2], bixbyite [Mn2O3] and K -birnessite [K4Mn14O27 8H2O]). In the absence of bacteria, pyrolusite and bixbyite oxidized biogenic uraninite (UO2[s]) to soluble U(VI) species, wit...

The Importance of Kinetics and Redox in the Biogeochemical Cycling of Iron in the Surface Ocean

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...