Metal (
            <scp>U</scp>
            ,
            <scp>Fe</scp>
            ,
            <scp>Mn</scp>
            ,
            <scp>Hg</scp>
            ) Cycling

Moore, Charles M.; DiChristina, Thomas J.

doi:10.1002/0471263397.env124

Cited by 1 publication

(1 citation statement)

References 74 publications

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“…With this method we could show that the uranium geochemistry in multispecies biofilms is not homogeneous, but heterogeneous and influenced by the presence of different bacteria creating different ecological niches with different geochemical conditions within biofilms leading to precipitated and reduced uranium species. Both mechanisms have a strong influence on the mobility of uranium in nature (57).…”

Section: Resultsmentioning

confidence: 99%

Identification of Fluorescent U(V) and U(VI) Microparticles in a Multispecies Biofilm by Confocal Laser Scanning Microscopy and Fluorescence Spectroscopy

Großmann

Arnold

Krawczyk-Bärsch

et al. 2007

Environ. Sci. Technol.

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Fluorescent uranium(V) and uranium(VI) particles were observed for the first time in vivo by a combined laser fluorescence spectroscopy and confocal laser scanning microscopy approach in a living multispecies biofilm grown on biotite plates. These particles ranged between 1 and 7 um in width and up to 20 microm in length and were located at the bottom and at the edges of biofilms colonies. Analysis of amplified 16S rRNA fragments and fluorescence in situ hybridization were used to characterize the biofilm communities. Laser fluorescence spectroscopy was used to identify these particles. The particles showed either a characteristic fluorescence spectrum in the wavelength range of 415-475 nm, indicative for uranium(V), or in the range of 480-560 nm, which is typical for uranium(VI). Particles of uranium(V) as well as uranium(VI) were simultaneously observed in the biofilms. These uranium particles were attributed for uranium(VI) to biologically mediated precipitation and for uranium(V) to redox processes taking place within the biofilm. The detection of uranium(V) in a multispecies biofilm was interpreted as a short-lived intermediate of the uranium(VI) to uranium(IV) redox reaction. Its presence clearly documents that the uranium(VI) reduction is not a two electron step but that only one electron is involved.

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Section: Resultsmentioning

confidence: 99%