- Title
- Effects of hyper-enriched reactive Fe on sulfidisation in a tidally inundated acid sulfate soil wetland
- Creator
- Keene, Annabelle; Johnston, Scott; Bush, Richard; Sullivan, Leigh; Burton, Edward; McElnea, Angus; Ahern, Col; Powell, Bernard
- Date
- 2011
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99652
- Identifier
- vital:10400
- Identifier
-
https://doi.org/10.1007/s10533-010-9461-2
- Identifier
- ISSN:0168-2563
- Abstract
- Solid phase Fe and S fractions were examined in an acid sulfate soil (ASS) wetland undergoing remediation via tidal inundation. Considerable diagenetic enrichment of reactive Fe(III) oxides (HCl- and dithionite-extractable) occurred near the soil surface (0-0.05 m depth), where extremely large concentrations up to 3534 μmol/g accounted for ~90% of the total Fe pool. This major source of reactive Fe exerts a substantial influence on S cycling and the formation, speciation and transformation of reduced inorganic S (RIS) in tidally inundated ASS. Under these geochemical conditions, acid volatile sulfide (AVS; up to 57 μmol/g) and elemental sulfur (S0; up to 41 μmol/g) were the dominant fractions of RIS in near surface soils. AVS-S to pyrite-S ratios exceeded 2.9 near the surface, indicating that abundant reactive Fe favoured the accumulation of AVS minerals and S0 over pyrite. This is supported by the significant correlation of poorly crystalline Fe with AVS-S and S0-S contents (r = 0.83 and r = 0.85, respectively, P < 0.01). XANES spectroscopy provided direct evidence for the presence of a greigite-like phase in AVS-S measured by chemical extraction. While the abundant reactive Fe may limit the transformation of AVS minerals and S0 to pyrite during early diagenesis (~5 years), continued sulfidisation over longer time scales is likely to eventually lead to enhanced sequestration of S within pyrite (with a predicted 8% pyrite by mass). These findings provide an important understanding of sulfidisation processes occurring in reactive Fe-enriched, tidally inundated ASS landscapes. © 2010 Springer Science+Business Media B.V.
- Publisher
- Springer Netherlands
- Relation
- Biogeochemistry Vol. 103, no. 1 (2011), p. 263-279
- Rights
- Copyright © 2010 Springer Science+Business Media B.V.
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- 0399 Other Chemical Sciences; 0402 Geochemistry; Acid sulfate soil; Reactive iron; Reduced inorganic sulfur; Sulfidisation; Tidal inundation; Wetland
- Full Text
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