The association of vanadium with humic acids

Szalay, A.; Szilágyi, M.

doi:10.1016/0016-7037(67)90093-2

Cited by 102 publications

(26 citation statements)

References 3 publications

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“…Yamazaki and Gohda (1990) also observed Mo depletion in coastal waters (Seto Inland Sea, North Pacific, minimum 69 nM), which was explained by scavenging of Mo as an organically associated species; a relationship, which was suggested earlier by Szalay and Szilagyi (1967) and Brumsack and Gieskes (1983). More recently, Tuit and Ravizza (2003) reported both, positive and negative Mo concentration anomalies in a region of nitrogen-fixation in the Eastern Equatorial Pacific (+5 nM, À3 nM), which presumably are related to biological processes.…”

Section: Introductionmentioning

confidence: 56%

Non-conservative behaviour of molybdenum in coastal waters: Coupling geochemical, biological, and sedimentological processes

Dellwig

Beck

Lemke

et al. 2007

Geochimica et Cosmochimica Acta

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, with values distinctly below the common summer level (by a factor of five). A direct relation between the loss of Mo and scavenging by freshly formed MnO x phases could not be inferred from our data because both metals revealed inverse patterns. Parallel to decreasing dissolved Mo concentrations dissolved Mn showed an increasing trend while particulate Mn decreased. Such finding is compatible with the formation of oxygen-depleted zones in aggregates, which provide suitable conditions for the rapid fixation of Mo and parallel release of Mn by chemically and/or microbially mediated processes. Our assumption is supported by biological (e.g. number of aggregate-associated bacteria) and sedimentological (e.g. aggregate abundance and size) parameters. The production of organic components (e.g. TEP) during breakdown of an algae bloom in July 2005 led to the formation of larger Mo-enriched aggregates, thus depleting the water column in dissolved Mo. After deposition on and incorporation into sandy tidal flats these aggregates are rapidly decomposed by microbial activity. Pore water profiles document that during microbial decomposition of these aggregates, substantial amounts of Mo are released and may replenish and even enrich Mo in the open water column. We postulate a conceptual model for the observed non-conservative behaviour of Mo in coastal waters, which is based on the tight coupling of geochemical, biological, and sedimentological processes.

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Section: Introductionmentioning

confidence: 56%

Non-conservative behaviour of molybdenum in coastal waters: Coupling geochemical, biological, and sedimentological processes

Dellwig

Beck

Lemke

et al. 2007

Geochimica et Cosmochimica Acta

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“…The extent of any mobility is determined by edaphic factors, notably the presence of reducing agents. Several workers have demonstrated the ability of soil organic matter to reduce pentavalent vanadium to the tetravalent state (Szalay and Szilagy, 1967;Goodman and Cheshire, 1975), and it may be possible that vanadium is mobilised in soils as a cationic complex.…”

Section: Geochemistry and Soilsmentioning

confidence: 99%

Vanadium uptake by higher plants: Some recent developments

Morrell

Lepp

Phipps

1986

Environ Geochem Health

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The occurrence of vanadium in the biosphere, and the possible roles this element may play in the metabolism of living organisms, especially higher plants, are discussed. The aqueous chemistry of the element is reviewed, and the chemical properties of the element are related to those of soils and plants. Evidence is present for a biotransformation of vanadium from vanadate (VO 3 (-) ) to vanadyl (VO(2+)) during uptake by plants, based on tissue analysis and ESR spectra. The significance of this process on the potential impact of vanadium in the biosphere is discussed.

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“…Reduction of V(V) is assumed to be caused by sulphide (Wehrli and Stumm 1989;Wanty and Goldhaber 1992) leading to particle-reactive species which precipitate as oxyhydroxides (Wehrli and Stumm 1989) or form stable complexes with humic acids (Szalay and Szilágyi 1967).…”

Section: Introductionmentioning

confidence: 99%

Trace metal dynamics in the water column and pore waters in a temperate tidal system: response to the fate of algae-derived organic matter

et al. 2009

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Tidal and seasonal behaviour of the redox-sensitive trace metals Mn, Fe, Mo, U, and V have been investigated in the open-water column and shallow pore waters of the backbarrier tidal flats of the island of Spiekeroog (Southern North Sea) in 2002 and 2007.The purpose was to study the response of trace metal cycles on algae blooms, which are assumed to cause significant changes in the redox state of the entire ecosystem. Trace metal data were complemented by measurements of nutrients and enumeration of algae cells in 2007. Generally, Mn and V show a tidal cyclicity in the water column with maximum values during low tide which is most pronounced in summer due to elevated microbial activity in the sediments. Mo and U behave almost conservatively throughout the year with slightly increasing levels towards high tide. Exceptions are observed for both metals after summer algae blooms. Thus, the seasonal behaviour of the trace metals appear to be significantly influenced by productivity in the water column as the occurrence of algae blooms is associated with an intense release of organic matter (e.g. transparent exopolymer particles, TEP) thereby forming larger organic-rich aggregates. Along with elevated temperatures in summer, the deposition of such aggregates favours microbial activity within the surface sediments and release of DOC, nutrients and trace metals (Mn, Mo and V) during the degradation of the aggregates. Additionally, pronounced reducing conditions lead to the reduction of Mn(IV)-oxides and Fe(III)-(oxihydr)oxides, thereby releasing formerly scavenged compounds as V and phosphate. Therefore, pore-water profiles show significant enrichments in trace metals especially from July to September. Finally, the trace metals are released to the open water column via draining pore waters (esp. Mo, Mn, and V) and/or fixed in the sediment as sulphides (Fe, Mo) and bound to organic matter (U). Nonconservative behaviour of Mo in oxygenated seawater, first observed in the investigation area by Dellwig et al. (Geochim Cosmochim Acta 71:2745-2761, 2007a, was shown to be a recurrent phenomenon which is closely coupled to bacterial activity after the breakdown of algae blooms. In addition to the postulated fixation of Mo in oxygen-depleted microzones of the aggregates or by freshly formed organic matter, a direct removal of Mo from the water column by reduced sediment surfaces may also play an important role.

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The association of vanadium with humic acids

Cited by 102 publications

References 3 publications

Non-conservative behaviour of molybdenum in coastal waters: Coupling geochemical, biological, and sedimentological processes

Non-conservative behaviour of molybdenum in coastal waters: Coupling geochemical, biological, and sedimentological processes

Vanadium uptake by higher plants: Some recent developments

Trace metal dynamics in the water column and pore waters in a temperate tidal system: response to the fate of algae-derived organic matter

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