Iron geochemical zonation in a tidally inundated acid sulfate soil wetland

Johnston, Scott G; Keene, Annabelle F; Bush, Richard T; Burton, Edward D; Sullivan, Leigh A; Isaacson, Lloyd S; McElnea, Angus E; Ahern, Colin R; Smith, Chelsea; Powell, Bernard

doi:10.1016/j.chemgeo.2010.11.014

Cited by 102 publications

(44 citation statements)

References 71 publications

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“…A significant correlation between porewater Eh and inundation frequency (r = 0.93, P < 0.05, n = 6 locations) was observed in the MRE, which is accordance with the reports on other coastal sediments (Castillo et al 2000;Davy et al 2011;Johnston et al 2011). Anastasiou and Brooks (2003) and Davy et al (2011) suggested that increasing inundation frequency induces a shorter exposure to the atmosphere and leads to sediment hypoxia in the lowlands, which is manifested in low sediment redox potentials and is associated with increasing concentrations of reduced substances (e.g., Fe(II) and sulfide).…”

Section: Amendment Measurementssupporting

confidence: 91%

“…Solid-phase sulfur species, including acid-volatile sulfide (AVS = H 2 S + FeS) and chromium-reducible sulfur (CRS = FeS 2 + S 0 ), were determined using 6 M HCl/0.1 M ascorbic acid and acidic CrCl 2 solutions, respectively, via the cold distillation method (Burton et al 2008). Nonsulfidic Fe(II) and FeS were calculated using the methods developed by Johnston et al (2011) and Burton et al (2011). In brief, FeS was calculated based on a stoichiometric relationship between Fe and S based on the difference of AVS and H 2 S (Fe/S = 1:1 in AVS − H 2 S).…”

Section: Sedimentary Analysismentioning

confidence: 99%

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Iron Reduction Along an Inundation Gradient in a Tidal Sedge (Cyperus malaccensis) Marsh: the Rates, Pathways, and Contributions to Anaerobic Organic Matter Mineralization

Luo

Zeng

Tong

et al. 2016

Estuaries and Coasts

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Incubation experiments were adopted to characterize the rates and pathways of iron reduction and the contributions to anaerobic organic matter mineralization in the upper 0-5 cm of sediments along a landscape-scale inundation gradient in tidal marsh sediments in the Min River Estuary, Southeast China. Similar sediment characteristics, singlespecies vegetation, varied biomass and bioturbation, distinct porewater pH, redox potential, and electrical conductivity values have resulted in a unique ecogeochemical zonation along the inundation gradient. Decreases in solid-phase Fe(III) and increases in nonsulfidic Fe(II) and iron sulfide were observed in a seaward direction. Porewater Fe 2+ was only detected in the upland area. High rates of iron reduction were observed in incubation jars, with significant accumulations of nonsulfidic Fe(II), moderate accumulations of iron sulfides, and negligible accumulations of porewater Fe 2+ . Most of the iron reduction was microbially mediated rather than coupled to reduced sulfides. Microbial iron reduction accounted for 20-89 % of the anaerobic organic matter mineralization along the inundation gradient. The rate and dominance of microbial iron reduction generally decreased in a seaward direction. The contributions of microbial iron reduction to anaerobic organic matter mineralization depended on the concentrations of bioavailable Fe(III), the spatial distribution of which was significantly related to tidal inundation. Our results clearly showed that microbial iron reduction in the upper sediments along the gradient is highly dependent on spatial scales controlled primarily by tidal inundation.

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Section: Amendment Measurementssupporting

confidence: 91%

Section: Sedimentary Analysismentioning

confidence: 99%

Iron Reduction Along an Inundation Gradient in a Tidal Sedge (Cyperus malaccensis) Marsh: the Rates, Pathways, and Contributions to Anaerobic Organic Matter Mineralization

Luo

Zeng

Tong

et al. 2016

Estuaries and Coasts

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“…It is well-known that pH plays an important role in metal speciation, solubility, and complexation. For example, ferrous iron Fe(II) is often dominant in acidic reducing environments [26,27]. Under acidic oxidising conditions, ferric species [Fe(III)] in the form of iron oxyhdrosulfate (e.g., Schwertmannite, Jarosite) minerals are precipitated [26,28].…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Binding of Protons, Al and Fe to Biochar at Different pH Values and Soluble Metal Concentrations

Dang

Marschner

Fitzpatrick

et al. 2018

Water

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Biochar can retain large amounts of protons and metals in the drainage water from acid sulfate soils and mine sites. Metal sorption can, however, be influenced by many factors, such as pH and metal composition. This study investigated proton, Al, and Fe retention capacity of eucalyptus biochar (1% w/v) at different pH and metal concentrations. In the absence of metals, the biochar had a high proton binding capacity, (up to 0.035 mmol of H + ), whereas its capacity to retain hydroxide ions was limited. A batch experiment was carried out at pH 4 and pH 7 with 10 −6 , 10 −5 , 10 −4 , 10 −3 , and 10 −2 M of added Fe or Al. Added metals precipitated considerably prior to addition of the biochar except that Al remained highly soluble at pH 4. The biochar had a high retention capacity for Al and Fe; at high (>1 mM) concentrations, over 80% of soluble metals were retained. Metal competition for binding sites of both Al and Fe at different ratios was investigated, but increasing concentrations of one metal did not reduce retention of the other. The results confirmed that biochar has high metal binding capacity under both acidic and neutral conditions.

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“…<1 m deep) from East Trinity, Australia (16°56 0 33 00 S, 145 48 0 9 00 E) as described in Johnston et al (2011a). Jarosite accretions were present in macropores and fissures of the upper sulfuric horizon (to 1 m depth) (Johnston et al, 2011a).…”

Section: Natural Jarosite Rich Soil Materialsmentioning

confidence: 88%