Bacterially mediated iron cycling and associated biogeochemical processes in a subtropical shallow coastal aquifer: implications for groundwater quality

Lin, Chaofeng, Larsen, Eloise I., Larsen, Genevieve R., Cox, Malcolm E., & Smith, James J. (2012) Bacterially mediated iron cycling and associated biogeochemical processes in a subtropical shallow coastal aquifer: implications for groundwater quality. Hydrobiologia.

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Bacterially mediated iron redox cycling exerts a strong influence on groundwater geochemistry, but few studies have investigated iron biogeochemical processes in coastal alluvial aquifers from a microbiological viewpoint. The shallow alluvial aquifer located adjacent to Poona estuary on the subtropical Southeast Queensland coast represents a redox-stratified system where iron biogeochemical cycling potentially affects water quality. Using a 300 m transect of monitoring wells perpendicular to the estuary, we examined groundwater physico-chemical conditions and the occurrence of cultivable bacterial populations involved in iron (and manganese, sulfur) redox reactions in this aquifer. Results showed slightly acidic and near-neutral pH, suboxic conditions and an abundance of dissolved iron consisting primarily of iron(II) in the majority of wells. The highest level of dissolved iron(III) was found in a well proximal to the estuary most likely a result of iron curtain effects due to tidal intrusion. A number of cultivable, (an)aerobic bacterial populations capable of diverse carbon, iron, or sulfur metabolism coexisted in groundwater redox transition zones. Our findings indicated aerobic, heterotrophic respiration and bacterially mediated iron/sulfur redox reactions were integral to carbon cycling in the aquifer. High abundances of dissolved iron and cultivable iron and sulfur bacterial populations in estuary-adjacent aquifers have implications for iron transport to marine waters. This study demonstrated bacterially mediated iron redox cycling and associated biogeochemical processes in subtropical coastal groundwaters using culture-based methods.

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5 citations in Scopus
4 citations in Web of Science®
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ID Code: 50983
Item Type: Journal Article
Refereed: Yes
Additional Information: Springer Online First publication
Additional URLs:
Keywords: Alluvial Aquifer, Iron Transport, Organic Matter Oxidation, Biofouling, Subtropical Australia
DOI: 10.1007/s10750-012-1184-z
ISSN: 1573-5117
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2012 Springer
Copyright Statement: The original publication is available at SpringerLink
Deposited On: 19 Jun 2012 22:22
Last Modified: 23 Jun 2012 04:57

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