Microbial Fe(III) oxide reduction and Fe cycling in iron-rich freshwater wetland sediments
- Univ. of Alabama, Tuscaloosa, AL (United States)
The dynamics of Fe cycling and the interaction between microbial Fe(III) oxide reduction and other anaerobic microbial respiratory processes were examined in Fe-rich, sulfate-poor freshwater wetland sediments. Sediment incubation experiments demonstrated that reduction of Fe(III) oxides (amorphous, soluble in dilute HCl) dominated anaerobic carbon mineralization at Fe(III) concentrations in excess of 10 mmol per liter wet sediment. The kinetics of Fe(III) reduction were found to be first-order with respect to the concentration of Fe(III) oxide, although estimated first-order rate constants varied in relation to the absolute rates of Fe(III) reduction, suggesting a co-dependency on the concentration of easily degradable organic carbon. High concentrations of amorphous Fe(III) oxides (10-100 mmol L wet sed {sup -1}) were found in surface sediments (0-3 cm) of unvegetated zones of the wetland and in the rhizosphere (0-10 cm) of emergent aquatic plants, sufficient (based on sediment incubation experiments) to allow Fe(III)-reducing bacteria (FeRB) to dominate anaerobic carbon mineralization. A rapid redox cycling of Fe is apparent in these localized zones based on observed rates of Fe(III) reduction and the abundance/depth distribution of Fe(Ill) oxides. Preliminary culture enrichment studies indicate that FeRB present in these sediments are capable of metabolizing a range of both natural and contaminant aromatic hydrocarbons, which suggests a potential for utilization of natural and/or artificial Fe-rich wetland systems for organic contaminant bioremediation.
- OSTI ID:
- 210503
- Report Number(s):
- CONF-9509139-; TRN: 95:008324-0368
- Resource Relation:
- Conference: 7. ACS special symposium: emerging technologies in hazardous waste management, Atlanta, GA (United States), 17-20 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Emerging technologies in hazardous waste management VII; Tedder, D.W. [ed.]; PB: 1352 p.
- Country of Publication:
- United States
- Language:
- English
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