Computer Science
Scientific paper
Jan 2012
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012gecoa..77..444f&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 77, p. 444-456.
Computer Science
Scientific paper
Recent studies on the microbial reduction of synthetic iron oxide colloids showed their superior electron accepting property in comparison to bulk iron oxides. However, natural colloidal iron oxides differ in composition from their synthetic counterparts. Besides a potential effect of colloid size, microbial iron reduction may be accelerated by electron-shuttling dissolved organic matter (DOM) as well as slowed down by inhibitors such as arsenic. We examined the microbial reduction of OM- and arsenic-containing ferrihydrite colloids. Four effluent fractions were collected from a soil column experiment run under water-saturated conditions. Ferrihydrite colloids precipitated from the soil effluent and exhibited stable hydrodynamic diameters ranging from 281 (±146) nm in the effluent fraction that was collected first and 100 (±43) nm in a subsequently obtained effluent fraction. Aliquots of these oxic effluent fractions were added to anoxic low salt medium containing diluted suspensions of Geobacter sulfurreducens. Independent of the initial colloid size, the soil effluent ferrihydrite colloids were quickly and completely reduced. The rates of Fe2+ formation ranged between 1.9 and 3.3 fmol h-1 cell-1, and are in the range of or slightly exceeding previously reported rates of synthetic ferrihydrite colloids (1.3 fmol h-1 cell-1), but greatly exceeding previously known rates of macroaggregate-ferrihydrite reduction (0.07 fmol h-1 cell-1). The inhibition of microbial Fe(III) reduction by arsenic is unlikely or overridden by the concurrent enhancement induced by soil effluent DOM. These organic species may have increased the already high intrinsic reducibility of colloidal ferrihydrite owing to quinone-mediated electron shuttling. Additionally, OM, which is structurally associated with the soil effluent ferrihydrite colloids, may also contribute to the higher reactivity due to increasing solubility and specific surface area of ferrihydrite. In conclusion, ferrihydrite colloids from soil effluents can be considered as highly reactive electron acceptors in anoxic environments.
Bosch Julian
Braunschweig Juliane
Fritzsche Andreas
Heister Katja
Meckenstock Rainer U.
No associations
LandOfFree
Fast microbial reduction of ferrihydrite colloids from a soil effluent does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fast microbial reduction of ferrihydrite colloids from a soil effluent, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fast microbial reduction of ferrihydrite colloids from a soil effluent will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-910020