Microbiological and Geochemical Characterization of Microbial Fe(III) Reduction in Salt Marsh Sediments
作者:
Kristine L. Lowe, Thomas J. Dichristina, Alakendra N. Roychoudhury, Philippe Van Cappellen,
期刊:
Geomicrobiology Journal
(Taylor Available online 2000)
卷期:
Volume 17,
issue 2
页码: 163-178
ISSN:0149-0451
年代: 2000
DOI:10.1080/01490450050023836
出版商: Informa UK Ltd
关键词: Dissimilatory Feiii Reduction Redox Zonation Salt Marsh Sediments Sulfate Reduction
数据来源: Taylor
摘要:
Population densities of anaerobic Fe(III)-reducing bacteria (FeRB) and aerobic heterotrophs were inversely correlated in the surficial (0-2 cm) layers of Sapelo Island, Georgia, salt marsh sediments. In surficial sediments where densities of aerobic heterotrophs were low, the density of culturable FeRB correlated positively with the concentration of amorphous Fe(III) oxyhydroxides extractable by ascorbate. High FeRB densities and a decrease with depth of ascorbate-extractable Fe(III) were observed in the upper 6 cm of a tidal creek core. Culturable sulfate-reducing bacteria (SRB) and SRB-targeted rRNA signals were also detected in the upper 6-cm depth. The disappearance of FeRB below 6 cm, however, coincided with a large increase in the abundance of SRB. Thus, when FeRB are not limited by the availability of readily reducible amorphous Fe(III) oxyhydroxides, FeRB may outcompete SRB for growth substrates.Shewanella putrefaciens- andGeobacteraceae-targeted rRNA signals were at or below detection limits in all sediment samples, indicating that these FeRB are not predominant members of the active FeRB populations. The ubiquitous presence of FeRB at the sites studied challenges the traditional view that dissimilatory Fe(III) reduction is not an important pathway of organic carbon oxidation in salt marsh sediments.
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