Comparative geochemistry of cadmium, rhenium, uranium, and molybdenum in continental margin sediments

Sundby, Bjørn; Martinez, Philippe; Gobeil, Charles

doi:10.1016/j.gca.2003.08.011

Cited by 145 publications

(75 citation statements)

References 38 publications

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“…Additionally, as reported for marine (e.g. Shaw et al, 1990;Chaillou et al, 2002;Sundby et al, 2004) and freshwater (e.g. Widerlund et al, 2002;Audry et al, 2010;Couture et al, 2010) environments, early diagenesis controls the post-depositional redistribution of trace elements through the destabilization of trace element-bearing phases and subsequent authigenic mineral precipitations.…”

Section: Introductionmentioning

confidence: 71%

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

et al. 2011

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Abstract. This study reports the very first results on highresolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m −2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe-and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe-and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe-and Mnoxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of auCorrespondence to: S. Audry (stephane.audry@get.obs-mip.fr) thigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

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Section: Introductionmentioning

confidence: 71%

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

et al. 2011

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“…The wide range in natural settings renders 668 it difficult to tease out the effects of modest amounts of added labile OM at any given site. One 669 other study, Sundby et al (2004), has examined redox elemental distributions in coastal and 670 estuarine sediments in a way that enables direct comparison with the flux estimates made for the 671 Strait of Georgia study. We note that for low sedimentation rates (0.03 to 0.64 g cm -2 y -1 ) and low 672 organic metabolic rates (0.2 -2.2 mg C cm -2 y -1 ), both studies produce surprisingly similar results 673 in the rates of redox element sequestration, with the Strait of Georgia results generally exhibiting 674 higher rates for Mo, Cd, Re and U, although ranges do overlap.…”

Section: Comparison Of the Gvrd Core Sites 663mentioning

confidence: 99%

“…688 Sundby et al (2004) concluded that slow kinetic reactions must be at play to explain Cd, Re, U 689…”

Section: Comparison Of the Gvrd Core Sites 663mentioning

confidence: 99%

“…GVRD-3 appears to have enhanced OC oxidation rates and both sites exhibit large inventories of 731 U, which may be a response to the abundance of reactive OM and attendant microbial activity 732 (Lovely et al, 1991;Sundby et al, 2004). The reversed profiles for Re, U and Mo at GVRD-2, 733 which increase toward the sediment surface, might be produced by enhanced OM loadings 734 following 1966, when the Lions Gate outfall was constructed, but for neither GVRD-2 nor 735 GVRD-3 is there a compelling image of disturbance written in the redox elements.…”

Section: Conclusion 698mentioning

confidence: 99%

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Sediment redox tracers in Strait of Georgia sediments – Can they inform us of the loadings of organic carbon from municipal wastewater?

Macdonald

Johannessen²,

Gobeil³

et al. 2008

Marine Environmental Research

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“…Accumulation rates of U, Mo, and Re have been determined at several locations with water depths less than 1000 m, including sites on both the Pacific (Zheng et al, 2000(Zheng et al, , 2002aMcManus et al, 2005;Morford and Emerson, 1999;Nameroff et al, 2002;Morford et al, 2005) and Atlantic (Zheng et al, 2002a;Sundby et al, 2004;this work) margins. Studies on the Pacific margin have included several locations in the California borderlands with low bottom water O 2 levels.…”

Section: Importance Of Shallow Sediments For Marine Budgets Of U Rementioning

confidence: 99%

Insights on geochemical cycling of U, Re and Mo from seasonal sampling in Boston Harbor, Massachusetts, USA

Morford

Martin

Kalnejais

et al. 2007

Geochimica et Cosmochimica Acta

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3Benthic chamber experiments including the nonreactive solute tracer, Br -, indicated that sediment irrigation was very important to solute exchange at the study site.The enhancement of sediment-seawater exchange due to irrigation was determined for the nonreactive tracer (Br -), TCO 2 , NH 4 + , U and Mo. The comparisons between these solutes showed that reactions within and around the burrows were very important for modulating the Mo flux, but less important for U. The effect of these reactions on Mo exchange was highly variable, enhancing Mo (and, to a lesser extent, U) uptake at times of relatively modest irrigation, but inhibiting exchange when irrigation rates were faster.These results reinforce the observation that Mo can be released to and removed from pore waters via sedimentary reactions.The removal rate of U and Mo from seawater by sedimentary reactions was found to agree with the rate of accumulation of authigenic U and Mo in the solid phase. The fluxes of U and Mo determined by in situ benthic flux chamber measurements were the largest that have been measured to date. These results confirm that removal of redoxsensitive metals from continental margin sediments underlying oxic bottom water is important, and suggest that continental margin sediments play a key role in the marine budgets of these metals.4

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Comparative geochemistry of cadmium, rhenium, uranium, and molybdenum in continental margin sediments

Cited by 145 publications

References 38 publications

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

Sediment redox tracers in Strait of Georgia sediments – Can they inform us of the loadings of organic carbon from municipal wastewater?

Insights on geochemical cycling of U, Re and Mo from seasonal sampling in Boston Harbor, Massachusetts, USA

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