Corrosion of Copper Canisters Through Microbially Mediated Sulphate Reduction

ABSTRACTA biogeochemical model was developed with an aim to illustrate the transport and reaction processes that may be involved in copper canister corrosion by sulphide in a deep repository for nuclear waste. Sulphide concentrations in the groundwaters in Sweden are relatively low and are generally considered to be of little importance for corrosion of the copper canisters. Sulphate, however, is present in relatively large amounts (50-700 mg/L) and may be reduced to sulphide by reaction with organic matter. Mediated by microbes, the reduction rate may be increased considerably compared to abiotic reduction. Microbially mediated sulphate reduction occurs in many natural environments, provided that reactive organic matter is available. Groundwater analyses indicate relatively high concentrations of dissolved methane (up to 16 mg/L) which thermodynamically is a suitable reducing agent. This processes could occur in fractures inthe bedrock provided that substrates are continuously supplied and that there is a sink for the reaction products. In the repository, the copper canisters may provide a sink for sulphide that yields a favourable environment for the microbe population. The model domain includes a canister with surrounding backfill material intersected by a hydraulically conductive fracture. Transport of substrates and reaction products in the fracture and backfillas well as microbially mediated reaction at the fracture opening is included in the model. Results indicate that microbially produced sulphide could potentially contribute to canister corrosion.

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Chemoautotrophic symbionts in the gills of the bivalve mollusc Lucinoma borealis and the sediment chemistry of its habitat

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1986.0021 ◽

1986 ◽

Vol 227 (1247) ◽

pp. 227-247 ◽

Cited By ~ 61

Keyword(s):

Reduction Rate ◽

Gill Tissue ◽

Elemental Sulphur ◽

Sulphate Reduction ◽

Sediment Chemistry ◽

Dissolved Iron ◽

The Mean ◽

Low Levels ◽

High Concentrations ◽

Sulphur Species

Lucinoma borealis has enlarged gills, which contain numerous prokaryotes in specialized cells (bacteriocytes) in the subfilamentar region. The gills also contain high concentrations of elemental sulphur and of a c -type cytochrome. Homogenates of gill tissue show ribulosebisphosphate carboxylase and phosphoribulokinase activity; they also show activity for adenylylsulphate reductase, an enzyme concerned in the oxidation of sulphur, and will phosphorylate ADP on the addition of sulphite or sulphide. Fixation of bicarbonate by gill tissue from starved animals is enhanced in the presence of 100 μm sulphide. The sediment in which the animals live contains 1–6 μg atoms per litre of dissolved iron and hence there is very little dissolved sulphide, 200 nM, or less (80 nmol dm -3 sediment). Thiosulphate concentrations are also low, 300 nM, or less (120 nmol dm -3 sediment). In contrast, there are acid-labile sulphide concentrations up to 14 mmol dm -3 and elemental sulphur concentrations up to 4 mg atom per cubic decimetre of sediment. The mean sulphate reduction rate in the sediment varied seasonally with temperature over the range 1640–4920 nmol sulphate reduced per hour per cubic decimetre. L. borealis was usually found below the region of maximum sulphate reduction. Hydrogen, methane and carbon monoxide concentrations were all 160 nmol dm -3 , or less. Despite the low levels of dissolved sulphide the association between prokaryote and host appears to be able to exploit this habitat by the oxidation of reduced sulphur species; ways in which the bivalve may be able to extract these from the sediment are discussed. The bivalves may obtain half their carbon from the autotrophic prokaryotes.

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Pyrite geochemistry and fossil preservation in shales

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1985.0148 ◽

1985 ◽

Vol 311 (1148) ◽

pp. 167-169 ◽

Cited By ~ 7

Keyword(s):

Organic Matter ◽

Water Column ◽

Sulphate Reduction ◽

Pore Waters ◽

Anoxic Waters ◽

Iron Sulphides ◽

Diagenetic Reaction ◽

Fossil Preservation

As emphasized by Dr Seilacher in his introduction to this symposium, and illustrated in the contribution by Mr Martill, some of the most important examples of fossil Lagersätten occur in marine shales of Mesozoic age. Many of the factors that control the types and preservation of fossils are the same as those that affect the authigenic mineralogy and geochemistry of the shales, notably the degree of aeration or stagnation of the water column and the quantity and quality of the organic matter supplied to the sediment. Perhaps the most important diagenetic reaction in marine shales is sulphate reduction by bacteria that are obligate anaerobes. They can operate in anoxic waters or in ‘reducing microenvironments’ (such as concentrations of organic matter, or enclosed voids within shells) in sediments whose pore waters are kept generally oxic by the effects of burrowing organisms. Sulphate is reduced to sulphide and in the presence of reduced iron this can be precipitated as iron sulphides, normally found in ancient sediments in the form of pyrite. Pyrite is thus a key mineral in studying shale diagenesis, for its geochemistry as well as for its direct importance in preserving fossils by replacement of soft-parts (see, for example, Stürmer 1984), of aragonitic shells (see, for example, Fisher 1985) and by forming internal moulds of chambered shells (see, for example, Hudson & Palframan 1969; Hudson 1982).

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Gas-phase oxidation of butene-2

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1958.0045 ◽

1958 ◽

Vol 244 (1238) ◽

pp. 331-344 ◽

Cited By ~ 6

Keyword(s):

Gas Phase ◽

Pressure Change ◽

Reaction Products ◽

Peroxide Formation ◽

Time Curve ◽

Pressure Time ◽

Initial Oxygen ◽

Gas Phase Oxidation ◽

Reactive Radicals ◽

Reaction Processes

The gas-phase thermal oxidation of butene-2 has been examined over the temperature range 289 to 395°C. No difference in behaviour of the cis and trans forms could be detected. At the higher temperatures the reaction resembled that of the oxidation of propylene in the shape of the pressure-time curve and in the identity of many of the reaction products. At the lower temperatures a decrease in pressure partly due to peroxide formation followed the induction period, and by the end of this time much of the initial oxygen had been consumed. At all temperatures excess olefin produced an apparent inhibiting effect manifested by a decreased yield of carbon monoxide and a fall-off in the maximum rate of pressure change and total pressure change. Reaction processes are discussed, and it is suggested that a peroxide precedes the formation of acetaldehyde. Branching occurs largely through reaction of acetyl radicals produced from the acetaldehyde. The inhibiting effects produced by excess olefin are attributed to the replacement of reactive radicals by the less reactive allylic-type radicals, and the addition reactions of olefin at higher olefin concentrations lead to polymerization and a low or negative overall pressure change.

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SHIMMER (1.0): a novel mathematical model for microbial and biogeochemical dynamics in glacier forefield ecosystems

Geoscientific Model Development ◽

10.5194/gmd-8-3441-2015 ◽

2015 ◽

Vol 8 (10) ◽

pp. 3441-3470 ◽

Cited By ~ 7

Author(s):

J. A. Bradley ◽

A. M. Anesio ◽

J. S. Singarayer ◽

M. R. Heath ◽

S. Arndt

Keyword(s):

Organic Matter ◽

Microbial Biomass ◽

Microbial Growth ◽

Model Development ◽

Biogeochemical Cycling ◽

Biogeochemical Model ◽

Model Parameters ◽

Glacier Forefield ◽

Unconstrained Model

Abstract. SHIMMER (Soil biogeocHemIcal Model for Microbial Ecosystem Response) is a new numerical modelling framework designed to simulate microbial dynamics and biogeochemical cycling during initial ecosystem development in glacier forefield soils. However, it is also transferable to other extreme ecosystem types (such as desert soils or the surface of glaciers). The rationale for model development arises from decades of empirical observations in glacier forefields, and enables a quantitative and process focussed approach. Here, we provide a detailed description of SHIMMER, test its performance in two case study forefields: the Damma Glacier (Switzerland) and the Athabasca Glacier (Canada) and analyse sensitivity to identify the most sensitive and unconstrained model parameters. Results show that the accumulation of microbial biomass is highly dependent on variation in microbial growth and death rate constants, Q10 values, the active fraction of microbial biomass and the reactivity of organic matter. The model correctly predicts the rapid accumulation of microbial biomass observed during the initial stages of succession in the forefields of both the case study systems. Primary production is responsible for the initial build-up of labile substrate that subsequently supports heterotrophic growth. However, allochthonous contributions of organic matter, and nitrogen fixation, are important in sustaining this productivity. The development and application of SHIMMER also highlights aspects of these systems that require further empirical research: quantifying nutrient budgets and biogeochemical rates, exploring seasonality and microbial growth and cell death. This will lead to increased understanding of how glacier forefields contribute to global biogeochemical cycling and climate under future ice retreat.

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The molecularly-uncharacterized component of nonliving organic matter in natural environments

Organic Geochemistry ◽

10.1016/s0146-6380(00)00096-6 ◽

2000 ◽

Vol 31 (10) ◽

pp. 945-958 ◽

Cited By ~ 459

Author(s):

J.I Hedges ◽

G Eglinton ◽

P.G Hatcher ◽

D.L Kirchman ◽

C Arnosti ◽

...

Keyword(s):

Organic Matter ◽

Natural Environments

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Consequences of nutrient load reductions for carbon and alkalinity dynamics within the region of freshwater influence of River Elbe

10.5194/egusphere-egu21-1716 ◽

2021 ◽

Author(s):

Johannes Paetsch ◽

Helmuth Thomas

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Sulfate Reduction ◽

Biogeochemical Model ◽

Time Interval ◽

Nutrient Loads ◽

Organic Matter Degradation ◽

Strong Decrease ◽

Nitrogen And Phosphorus ◽

River Elbe

Since the early eighties of the 20th century nitrogen and phosphorus loads of the River Elbe, a river entering the North European Shelf at the southeastern coast, have decreased by a factor of about four. This resulted in a reduction of the eutrophication status in the adjacent German Bight and the coastal waters west of Denmark. In addition, benthic carbon and alkalinity pools have changed due to 1- changed carbon loads and, 2- changed decay pathways of benthic organic carbon.We investigate the consequences of observed nutrient and organic loads by rivers with a 3D-biogeochemical model including a 3D-early diageneses model within the sediment for the time 1979 - 2014. &#160;&#160;The results show a strong decrease of benthic carbon rather due to decreasing nutrient loads and subsequent autochthonous biological production than changes in organic loads. The export of inorganic carbon from the sediment is related to the magnitude of benthic organic carbon and cannot explain the strong decrease of the benthic POC pool.&#160;During the time until the early nineties aerobic degradation increases, whereas denitrification and sulfate reduction as organic matter degradation pathway decreases.Alkalinity production due to benthic organic matter degradation decreases over the first half of the investigated time interval and keeps constant during the second half. Denitrification and sulfate reduction dominate the mechanisms decreasing the alkalinity export. Benthic nitrification consuming alkalinity strongly increases during the first half of the time dampening the decrease of alkalinity export.

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Structural Characterization of Dissolved Organic Matter in Permafrost Peatland Lakes

Water ◽

10.3390/w12113059 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3059

Author(s):

Diogo Folhas ◽

Armando C. Duarte ◽

Martin Pilote ◽

Warwick F. Vincent ◽

Pedro Freitas ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Complex Mixture ◽

Resonance Spectroscopy ◽

Hudson Bay ◽

Microbial Decomposition ◽

Thermokarst Lakes ◽

Geochemical Properties ◽

High Concentrations ◽

Analytical Approaches

Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the DOM from a set of peatland thermokarst lakes that are known to be intense sites of microbial decomposition and methane emission. Samples were collected at different depths from three thermokarst lakes in the Sasapimakwananisikw (SAS) River valley near the eastern Hudson Bay community of Kuujjuarapik–Whapmagoostui (Nunavik, Canada). Samples were analyzed by spectrofluorometry, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and elemental analysis. Fluorescence analyses indicated considerable amounts of autochthonous DOM in the surface waters of one of SAS 1A, indicating a strong bioavailability of labile DOM, and consequently a greater methanogenic potential. The three lakes differed in their chemical composition and diversity, suggesting various DOM transformations phenomena. The usefulness of complementary analytical approaches to characterize the complex mixture of DOM in permafrost peatland waters cannot be overlooked, representing a first step towards greater comprehension of the organic geochemical properties of these permafrost-derived systems.

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Effects of Carbon Addition on Dissimilatory Fe(III) Reduction in Freshwater Marsh and Meadow Wetlands

Sustainability ◽

10.3390/su10114309 ◽

2018 ◽

Vol 10 (11) ◽

pp. 4309 ◽

Cited By ~ 1

Author(s):

Xiaoyan Zhu ◽

Yuxiang Yuan ◽

Ming Jiang

Keyword(s):

Iron Reduction ◽

Reduction Rate ◽

Negative Relationship ◽

Sanjiang Plain ◽

Freshwater Marsh ◽

Freshwater Wetlands ◽

Natural Environments ◽

Carbon Addition ◽

Soil Slurry ◽

The Sanjiang Plain

The progress of dissimilatory iron(III) reduction is widespread in natural environments, particularly in anoxic habitats; in fact, wetland ecosystems are considered as “hotspots” of dissimilatory Fe(III) reduction. In this study, we conducted soil slurry and microbial inoculation anaerobic incubation with glucose, pyruvate, and soluble quinone anthraquinone-2,6-disulphonate (AQDS) additions in freshwater marsh and meadow wetlands in the Sanjiang Plain, to evaluate the role of carbon addition in the rates and dynamics of iron reduction. Dissimilatory Fe(III) reduction in marsh wetlands responded more quickly and showed twice the potential for Fe(III) reduction as that in meadow wetland. Fe(III) reduction rate in marsh and meadow wetlands was 76% and 30%, respectively. Glucose had a higher capacity to enhance Fe(III) reduction than pyruvate, which provides valuable information for the further isolation of Fe reduction bacteria in pure culture. AQDS could dramatically increase potential Fe(III) reduction as an electron shuttle in both wetlands. pH exhibited a negative relationship with Fe(III) reduction. In view of the significance of freshwater wetlands in the global carbon and iron cycle, further profound research is now essential and should explore the enzymatic mechanisms underlying iron reduction in freshwater wetlands.

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Precipitation and Coagulation of Organic Substances in Bleachery Effluents of Pulp Mills

Water Science & Technology ◽

10.2166/wst.1993.0277 ◽

1993 ◽

Vol 27 (11) ◽

pp. 193-199 ◽

Cited By ~ 19

Author(s):

S. Beulker ◽

M. Jekel

Keyword(s):

Organic Matter ◽

Magnesium Hydroxide ◽

Chemical Treatment ◽

Organic Substances ◽

Soluble Organic Matter ◽

Pulp Mills ◽

High Chemical ◽

Physico Chemical ◽

Chlorinated Organic ◽

High Concentrations

The formation of chlorinated organic substances in bleachery effluents of pulp mills is avoided by changing the bleaching processes to nonchlorinating agents. However, high concentrations of poorly biodegradable and colored lignins are remaining. Precipitation can be one option in physico-chemical treatment of these waters. The influence of alum, lime and magnesium hydroxide as precipitation agents for two different bleachery wastewaters was investigated under various conditions. Alum prove to be the most effective precipitant. Application at an Al/DOC-ratio of 0.5 (g/g) yields a reduction of about 60 % of the soluble organic matter in chlorine-bleachery effluents at the pH = 5.5. Oxygen-bleachery effluents require only half of this specific dosage. Lime precipitation also causes low residual concentrations, but the high chemical demand leads to problems in application. The precipitation with magnesium hydroxide cannot be applied, because remaining concentrations of organic materials are quite high. The changes in bleaching processes are responsible for a new kind of wastewater, which has a significantly lower demand of precipitant

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