Sulfide complexation in surface seawater

Dyrssen, David

doi:10.1016/0304-4203(88)90045-x

Cited by 118 publications

(83 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In anoxic seawater Cd forms strong complexes with bisulfide in anoxic seawater (Dyrssen, 1988;Zhang and Millero, 1994;Luther and others, 1996;Al-Farawati and Van den Berg, 1999). Removal of Cd associated with sulfide is observed in both the Black Sea and Cariaco Basin, with concentrations at both locations reduced from maxima of ϳ120 pM close to the redoxcline to ϳ5 to 10 pM beneath it ( fig.…”

Section: The Geochemical Behavior Ofmentioning

confidence: 88%

“…Deep Atlantic concentrations are ϳ1.5 nM, compared with ϳ4.5 nM in the deep Pacific. Copper also forms strong complexes with dissolved sulfide (Dyrssen, 1988;Zhang and Millero, 1994;Al-Farawati and Van den Berg, 1999), though it is not clear whether Cu is complexed as Cu(I), Cu(II), or both by sulfide (for example Haraldsson and Westerlund, 1991;Mountain and Seward, 1999). Removal in association with sulfide results in the stripping of Cu from the Black Sea and the Table 2 Physical and geochemical characteristics of sites* * Compilation in Algeo and Lyons, 2006: see references therein.…”

Section: The Geochemical Behavior Ofmentioning

confidence: 99%

See 1 more Smart Citation

Controls on trace metal authigenic enrichment in reducing sediments: Insights from modern oxygen-deficient settings

Little

Vance

Lyons

et al. 2015

American Journal of Science

194

122

View full text Add to dashboard Cite

ABSTRACT. Any effort to reconstruct Earth history using variations in authigenic enrichments of redox-sensitive and biogeochemically important trace metals must rest on a fundamental understanding of their modern oceanic and sedimentary geochemistry. Further, unravelling the multiple controls on sedimentary enrichments requires a multi-element approach. Of the range of metals studied, most is known about the behavior of Fe, Mn, and Mo. In this study, we compare the authigenic enrichment patterns of these elements with a group whose behavior is not as well defined (Cd, Cu, Zn, and Ni) in three oxygen-poor settings: the Black Sea, the Cariaco Basin (Venezuela), and the Peru Margin. These three settings span a range of biogeochemical environments, allowing us to isolate the different controls on sedimentary enrichment. Our approach, relying on the covariation of elemental enrichment factors [EF, defined for element X as: EF X ‫؍‬ (X/Al) sample /(X/Al) lithogenic ], has previously been applied to Mo and U to elucidate paleoenvironmental information on, for example, benthic redox conditions, the particulate shuttle, and the evolution of water mass chemistry. We find two key controls on trace metal enrichment. First, the concentration of an element in the lithogenic background sediment (used in calculating EF X ) controls the magnitude of potential enrichment. Maximum enrichment factors of 376 and 800 are calculated for Mo (ϳ1 ppm in detrital sediments) and Cd (ϳ0.3 ppm), respectively, compared to values not greater than 17 in any setting for the other five metals (ϳ45 ppm to ϳ4.5 wt.% in detrital sediments). Second, there is a relationship between the aqueous concentration of the element in overlying seawater and its degree of enrichment in the sediment. We further identify four important processes for delivery of trace metals to the sediment. These are: (1) cellular uptake (especially important for Zn and Cd), (2) interaction/co-precipitation with sulfide (Mo, Cu, and Cd), (3) passive scavenging via the traditional particulate shuttle (Mo, Ni, and Cu), and (4) an association with the benthic Fe redox shuttle (Mn, Ni). Finally, we summarize the oceanic mass balance of Cd and Mo and place the first constraints on the contribution of reducing sediments to the oceanic mass balance of Cu, Zn, and Ni. We show that reducing sediments are the ultimate repository for up to half the total output flux of these elements from the oceanic dissolved pool.

show abstract

Section: The Geochemical Behavior Ofmentioning

confidence: 88%

Section: The Geochemical Behavior Ofmentioning

confidence: 99%

Controls on trace metal authigenic enrichment in reducing sediments: Insights from modern oxygen-deficient settings

Little

Vance

Lyons

et al. 2015

American Journal of Science

194

122

View full text Add to dashboard Cite

show abstract

“…If Pb-chloride is more readily available to adsorb to Fe-oxyhydroxide surfaces, it could explain why 77% of the Pb was associated with >100 nm particles at site D with pH 5, while 'truly dissolved' Pb-carbonate complexes could account for the large (79-100%)b 100 nm Pb-fractions at the other sites with pH > 7.5 (Table 2B). Ag forms strong sulphide complexes (Dyrssen, 1988) and association with the S-rich NPs at site D, and aggregation of these NPs into larger colloids at site A, could explain the Ag partitioning between filter fractions at these sites with hydrothermal activity. Mo tends to be depleted in reduced Fe-S-rich waters.…”

Section: Discussionmentioning

confidence: 99%

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

et al. 2012

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f oWe report on metal enrichment along a natural pH gradient owing to increased CO 2 degassing at cold, shallow seeps of Vulcano Island in the Mediterranean Sea, off Sicily. We assessed composition of unfiltered and filtered seawater (b100 nm) along acidic zones ranging between ambient and pH 5, and showed that most seep derived elements are present as nanoclusters which then aggregate into larger colloids while mixing with ambient seawater along a pH gradient. Size and elemental composition of such naturally occurring nanoparticles assessed by modern characterisation methods were in good agreement with the results from conventional analytical methods. We provide analytical evidence for the presence in the water column of a large fraction of seep derived elements (e.g. approximately 50% of iron, over 80% of Mn, 100% of Cr, S and Zn) in the form of nano sized particles (e.g. b 100 nm) even at typical open ocean pHs. We launch in situ sampling protocols and sample preparation procedures for multi-method suitable to obtain accurate measurements on nanoparticles from environmental samples. Based on our results a first insight to the formation of natural nanoparticles at cold CO 2 seeps is presented and the persistence of such nano-clusters in the surrounding seawater is stipulated.

show abstract

“…Cd is dissolved at lower sulphide (higher oxygen) concentrations than Zn due to the higher stability constants of Greenockite (CdS) (Dyrssen, 1988) (Figs. 1 and 2A±C).…”

Section: Mineql 1 Calculationsmentioning

confidence: 99%

The influence of salinity on the solubility of Zn and Cd sulphides in the Scheldt estuary

Gerringa

Baar

Nolting

et al. 2001

Journal of Sea Research

View full text Add to dashboard Cite

In the estuary of the river Scheldt, where an oxygen gradient exists in addition to the salinity gradient, redox processes will be of major importance for trace metal mobilisation. In this study, the in¯uence of salinity and pH on the redox processes of dissolved Zn and Cd sulphides is investigated together with the effects on the ratio of the dissolved Zn and Cd concentrations. The speciation of these metals is calculated with the chemical equilibrium programme mineql 1 . Zn sulphides are oxidised at lower oxygen concentrations than Cd sulphides, due to lower stability constants, causing a sudden increase or peak in the dissolved Zn/Cd ratio. The formation of dissolved Cd chloride complexes when oxidation occurs at high salinities S 15 increases the mobility of Cd, causing a decrease in the Zn/Cd peak of the total dissolved concentrations. The peak is three to four times smaller at S 15 than when oxidation occurs at S 2: The simple model calculations compare very well with ®eld data. The Scheldt estuary is suitable to illustrate these calculations. In the 1970s, the anoxic part of the estuary reached S 15±20; but since the early 1980s it has dropped to S 2±10: Historic data on metals in the estuary from 1978, 1987 and the 1990s were used to compare with the equilibrium calculations. The increase of the dissolved Zn/Cd peak at low salinity as a consequence, of the decreasing anoxic region is con®rmed well by the data. The good agreement between model calculations and ®eld data is a proof of the extreme importance of redox processes for the solubility of Zn and Cd sulphides in the estuary. q

show abstract

Sulfide complexation in surface seawater

Cited by 118 publications

References 7 publications

Controls on trace metal authigenic enrichment in reducing sediments: Insights from modern oxygen-deficient settings

Controls on trace metal authigenic enrichment in reducing sediments: Insights from modern oxygen-deficient settings

Metallic nanoparticle enrichment at low temperature, shallow CO2 seeps in Southern Italy

The influence of salinity on the solubility of Zn and Cd sulphides in the Scheldt estuary

Contact Info

Product

Resources

About