Discharge of weathering products from acid sulfate soils after a rainfall event, Tweed River, eastern Australia

MacDonald, Bennett; White, Ian; Åström, Mats E.; Keene, Annabelle F; Melville, M. D.; Reynolds, Jason K.

doi:10.1016/j.apgeochem.2007.07.004

Cited by 64 publications

(47 citation statements)

References 17 publications

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“…Pyrite is stable under anoxic conditions below the water table (Sammut et al 1996), but on exposure to air, which typically occurs when these sediments are developed for agriculture or urban use, pyrite is oxidized to sulfuric acid (Sammut et al 1996). Sulfuric acid reacts with clay minerals to release heavy metal ions, principally Al 3+ (Macdonald et al 2007). A rise in the water table or heavy rains can cause acidic and metal-rich waters to leach out of these sediments into estuaries (Russell & Helmke 2002, Macdonald et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Sulfuric acid reacts with clay minerals to release heavy metal ions, principally Al 3+ (Macdonald et al 2007). A rise in the water table or heavy rains can cause acidic and metal-rich waters to leach out of these sediments into estuaries (Russell & Helmke 2002, Macdonald et al 2007). Small acid discharges into estuaries are neutralized quickly by the alkalinity of seawater.…”

Section: Introductionmentioning

confidence: 99%

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Reduced salinity, but not estuarine acidification, is a cause of immune-suppression in the Sydney rock oyster Saccostrea glomerata

Green¹,

Barnes²

2010

Mar. Ecol. Prog. Ser.

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Acid sulfate soils (ASS) are a major problem around the world. Oxidation of these sulfide-rich sediments by anthropogenic disturbance results in production and release of sulfuric acid. Subsequent rise in the water table due to rain may result in sulfuric acid and heavy metal ions leaching out of the sediments into nearby estuaries, leading to their acidification. Anecdotal evidence exists that flood waters containing ASS leachate may cause adult Sydney rock oysters Saccostrea glomerata to become immune-suppressed, leading to higher mortality rates from the paramyxean parasite Marteilia sydneyi (aetiological agent of QX disease). In the current study, adult S. glomerata were exposed to a seawater matrix of varying salinity, sulfuric acid and Al 3+ for 48 h, and the expression of 7 genes involved in immunity were measured by quantitative reverse-transcription polymerase chain reaction. A change in salinity from 35 to 15 ppt caused a 1.7-fold down-regulation in the expression of peroxiredoxin 6 gene (p < 0.05). The expression of peroxiredoxin 6 was still down-regulated 5 d after oysters were returned to full-strength seawater (35 ppt). Changes in salinity, sulfuric acid and Al 3+ concentration had no effects on the expression of other target genes (p > 0.05). The effects of salinity, sulfuric acid and Al 3+ on the ability of immune genes to respond to microbial invasion were also investigated by exposing oysters to the seawater matrix for 40 h, followed by injection with heat-killed Vibrio alginolyticus bacteria. A drop in salinity coupled with V. alginolyticus injection resulted in down-regulation of peroxiredoxin 6 and C1q-like protein (p < 0.05). Apart from C1q-like protein, exposure to sulfuric acid and Al 3+ had no significant effects on the response of target genes to stimulation by V. alginolyticus (p > 0.05). These results support that reduced salinity, and not estuary acidification, is the main environmental stressor resulting in S. glomerata becoming immunocompromised during the QX disease risk period.KEY WORDS: Oyster · Saccostrea · Gene expression · Acidification · Environmental stress · Acid sulfate soils Resale or republication not permitted without written consent of the publisher

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reduced salinity, but not estuarine acidification, is a cause of immune-suppression in the Sydney rock oyster Saccostrea glomerata

Green¹,

Barnes²

2010

Mar. Ecol. Prog. Ser.

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“…The lack of OM input through litterfall diminishes microbial activity, reduces the electron pressure in the sediments, and redox potential (Eh) rises as oxygen penetrates the sediment. As a consequence, the formation of sulphuric acid by the oxidation of iron sulphides according to the equation (Macdonald et al 2007) and leaching of potentially toxic metals (Roos and Åström 2006) occur. The low productivity of the socalled acid sulphate soils can be attributed mainly to toxicity of aluminium and to nutrient deficiencies, especially of phosphorus (P).…”

Section: Introductionmentioning

confidence: 99%

Mangrove reforestation in Vietnam: the effect of sediment physicochemical properties on nutrient cycling

Oxmann

Pham²,

Schwendenmann

et al. 2009

Plant Soil

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Sediment physicochemical properties most likely control the reforestation success on degraded mangrove sites. Our objectives were (1) to determine the nutritional status of reforested mangrove stands; (2) to investigate the effects of the redox potential (Eh) and pH on phosphorus (P) and nitrogen (N) cycling; and (3) to assess the effect of pH on P speciation. Five transects were studied in replanted stands of the Saigon River Delta, Vietnam. Spatial gradients of sediment Eh and pH were affected by the tidal regime and pyrite oxidation. Sediment Al/Fe-P correlated with Eh or pH, depending on the sediment layer, whereas Ca-P, Morgan-P (available P) and leaf P were influenced by the pH. The highest concentrations of Al/Fe-P were recorded at pH 6.5 probably due to adsorption effects. Sediment Ca-P increased strongly at pH below 4 and above 6, reflecting the different pHdependent solubilities of individual Ca-P mineral species as shown by a newly developed method for P species quantification. A strong increase of available P and leaf P above pH 6, and positive correlations of available P vs Ca-P (P<0.001) and leaf P (P=0.004) suggest that the Morgan's reagent for available P determination solubilizes mainly thermodynamically less stable Ca-P compounds, which seem to fuel P plant uptake. Since foliar and sediment N:P ratios were influenced mainly by pH, shifts in pH likely cause limitation transitions. Overall, sediment pH rather than Eh was found to control the nutrient status.

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“…It is estimated that one tonne of sulfide produces approximately one and a half tonnes of sulfuric acid [3]. ASS in floodplains of the Tweed river (New South Wales, Australia) discharged approximately 110 kg of sulfuric acid per hectare in a few days of rain [5]. Drainage water seeping from sulfuric material (pH < 4) in ASS also contains high amounts of metals that are released due to the low pH.…”

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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Discharge of weathering products from acid sulfate soils after a rainfall event, Tweed River, eastern Australia

Cited by 64 publications

References 17 publications

Reduced salinity, but not estuarine acidification, is a cause of immune-suppression in the Sydney rock oyster Saccostrea glomerata

Reduced salinity, but not estuarine acidification, is a cause of immune-suppression in the Sydney rock oyster Saccostrea glomerata

Mangrove reforestation in Vietnam: the effect of sediment physicochemical properties on nutrient cycling

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

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